X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fscsi%2Fscsi_lib.c;h=f02f48a882a97b4150a7afe9eb403f1ce7f293fb;hb=refs%2Fheads%2Fvserver;hp=e30d3f2bf6fbbeac77572928d736c17bdac882b6;hpb=9bf4aaab3e101692164d49b7ca357651eb691cb6;p=linux-2.6.git diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index e30d3f2bf..f02f48a88 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -15,26 +15,28 @@ #include #include #include +#include +#include #include +#include #include #include #include #include #include -#include #include "scsi_priv.h" #include "scsi_logging.h" -#define SG_MEMPOOL_NR (sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool)) +#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) #define SG_MEMPOOL_SIZE 32 struct scsi_host_sg_pool { size_t size; char *name; - kmem_cache_t *slab; + struct kmem_cache *slab; mempool_t *pool; }; @@ -43,7 +45,7 @@ struct scsi_host_sg_pool { #endif #define SP(x) { x, "sgpool-" #x } -struct scsi_host_sg_pool scsi_sg_pools[] = { +static struct scsi_host_sg_pool scsi_sg_pools[] = { SP(8), SP(16), SP(32), @@ -62,37 +64,28 @@ struct scsi_host_sg_pool scsi_sg_pools[] = { }; #undef SP +static void scsi_run_queue(struct request_queue *q); /* - * Function: scsi_insert_special_req() + * Function: scsi_unprep_request() * - * Purpose: Insert pre-formed request into request queue. + * Purpose: Remove all preparation done for a request, including its + * associated scsi_cmnd, so that it can be requeued. * - * Arguments: sreq - request that is ready to be queued. - * at_head - boolean. True if we should insert at head - * of queue, false if we should insert at tail. + * Arguments: req - request to unprepare * - * Lock status: Assumed that lock is not held upon entry. - * - * Returns: Nothing + * Lock status: Assumed that no locks are held upon entry. * - * Notes: This function is called from character device and from - * ioctl types of functions where the caller knows exactly - * what SCSI command needs to be issued. The idea is that - * we merely inject the command into the queue (at the head - * for now), and then call the queue request function to actually - * process it. + * Returns: Nothing. */ -int scsi_insert_special_req(struct scsi_request *sreq, int at_head) +static void scsi_unprep_request(struct request *req) { - /* - * Because users of this function are apt to reuse requests with no - * modification, we have to sanitise the request flags here - */ - sreq->sr_request->flags &= ~REQ_DONTPREP; - blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request, - at_head, sreq, 0); - return 0; + struct scsi_cmnd *cmd = req->special; + + req->cmd_flags &= ~REQ_DONTPREP; + req->special = NULL; + + scsi_put_command(cmd); } /* @@ -118,18 +111,14 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) { struct Scsi_Host *host = cmd->device->host; struct scsi_device *device = cmd->device; + struct request_queue *q = device->request_queue; + unsigned long flags; SCSI_LOG_MLQUEUE(1, printk("Inserting command %p into mlqueue\n", cmd)); /* - * We are inserting the command into the ml queue. First, we - * cancel the timer, so it doesn't time out. - */ - scsi_delete_timer(cmd); - - /* - * Next, set the appropriate busy bit for the device/host. + * Set the appropriate busy bit for the device/host. * * If the host/device isn't busy, assume that something actually * completed, and that we should be able to queue a command now. @@ -146,12 +135,6 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) device->device_blocked = device->max_device_blocked; - /* - * Register the fact that we own the thing for now. - */ - cmd->state = SCSI_STATE_MLQUEUE; - cmd->owner = SCSI_OWNER_MIDLEVEL; - /* * Decrement the counters, since these commands are no longer * active on the host/device. @@ -159,113 +142,293 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) scsi_device_unbusy(device); /* - * Insert this command at the head of the queue for it's device. - * It will go before all other commands that are already in the queue. + * Requeue this command. It will go before all other commands + * that are already in the queue. * * NOTE: there is magic here about the way the queue is plugged if * we have no outstanding commands. * - * Although this *doesn't* plug the queue, it does call the request + * Although we *don't* plug the queue, we call the request * function. The SCSI request function detects the blocked condition * and plugs the queue appropriately. - */ - blk_insert_request(device->request_queue, cmd->request, 1, cmd, 1); + */ + spin_lock_irqsave(q->queue_lock, flags); + blk_requeue_request(q, cmd->request); + spin_unlock_irqrestore(q->queue_lock, flags); + + scsi_run_queue(q); + return 0; } -/* - * Function: scsi_do_req - * - * Purpose: Queue a SCSI request - * - * Arguments: sreq - command descriptor. - * cmnd - actual SCSI command to be performed. - * buffer - data buffer. - * bufflen - size of data buffer. - * done - completion function to be run. - * timeout - how long to let it run before timeout. - * retries - number of retries we allow. - * - * Lock status: No locks held upon entry. - * - * Returns: Nothing. - * - * Notes: This function is only used for queueing requests for things - * like ioctls and character device requests - this is because - * we essentially just inject a request into the queue for the - * device. - * - * In order to support the scsi_device_quiesce function, we - * now inject requests on the *head* of the device queue - * rather than the tail. - */ -void scsi_do_req(struct scsi_request *sreq, const void *cmnd, - void *buffer, unsigned bufflen, - void (*done)(struct scsi_cmnd *), - int timeout, int retries) +/** + * scsi_execute - insert request and wait for the result + * @sdev: scsi device + * @cmd: scsi command + * @data_direction: data direction + * @buffer: data buffer + * @bufflen: len of buffer + * @sense: optional sense buffer + * @timeout: request timeout in seconds + * @retries: number of times to retry request + * @flags: or into request flags; + * + * returns the req->errors value which is the the scsi_cmnd result + * field. + **/ +int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, + int data_direction, void *buffer, unsigned bufflen, + unsigned char *sense, int timeout, int retries, int flags) { - /* - * If the upper level driver is reusing these things, then - * we should release the low-level block now. Another one will - * be allocated later when this request is getting queued. - */ - __scsi_release_request(sreq); + struct request *req; + int write = (data_direction == DMA_TO_DEVICE); + int ret = DRIVER_ERROR << 24; - /* - * Our own function scsi_done (which marks the host as not busy, - * disables the timeout counter, etc) will be called by us or by the - * scsi_hosts[host].queuecommand() function needs to also call - * the completion function for the high level driver. - */ - memcpy(sreq->sr_cmnd, cmnd, sizeof(sreq->sr_cmnd)); - sreq->sr_bufflen = bufflen; - sreq->sr_buffer = buffer; - sreq->sr_allowed = retries; - sreq->sr_done = done; - sreq->sr_timeout_per_command = timeout; + req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); + + if (bufflen && blk_rq_map_kern(sdev->request_queue, req, + buffer, bufflen, __GFP_WAIT)) + goto out; - if (sreq->sr_cmd_len == 0) - sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); + req->cmd_len = COMMAND_SIZE(cmd[0]); + memcpy(req->cmd, cmd, req->cmd_len); + req->sense = sense; + req->sense_len = 0; + req->retries = retries; + req->timeout = timeout; + req->cmd_type = REQ_TYPE_BLOCK_PC; + req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; /* * head injection *required* here otherwise quiesce won't work */ - scsi_insert_special_req(sreq, 1); + blk_execute_rq(req->q, NULL, req, 1); + + ret = req->errors; + out: + blk_put_request(req); + + return ret; } - -static void scsi_wait_done(struct scsi_cmnd *cmd) +EXPORT_SYMBOL(scsi_execute); + + +int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, + int data_direction, void *buffer, unsigned bufflen, + struct scsi_sense_hdr *sshdr, int timeout, int retries) { - struct request *req = cmd->request; - struct request_queue *q = cmd->device->request_queue; - unsigned long flags; + char *sense = NULL; + int result; + + if (sshdr) { + sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); + if (!sense) + return DRIVER_ERROR << 24; + } + result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, + sense, timeout, retries, 0); + if (sshdr) + scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); - req->rq_status = RQ_SCSI_DONE; /* Busy, but indicate request done */ + kfree(sense); + return result; +} +EXPORT_SYMBOL(scsi_execute_req); - spin_lock_irqsave(q->queue_lock, flags); - if (blk_rq_tagged(req)) - blk_queue_end_tag(q, req); - spin_unlock_irqrestore(q->queue_lock, flags); +struct scsi_io_context { + void *data; + void (*done)(void *data, char *sense, int result, int resid); + char sense[SCSI_SENSE_BUFFERSIZE]; +}; + +static struct kmem_cache *scsi_io_context_cache; + +static void scsi_end_async(struct request *req, int uptodate) +{ + struct scsi_io_context *sioc = req->end_io_data; - if (req->waiting) - complete(req->waiting); + if (sioc->done) + sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); + + kmem_cache_free(scsi_io_context_cache, sioc); + __blk_put_request(req->q, req); } -void scsi_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer, - unsigned bufflen, int timeout, int retries) +static int scsi_merge_bio(struct request *rq, struct bio *bio) { - DECLARE_COMPLETION(wait); - - sreq->sr_request->waiting = &wait; - sreq->sr_request->rq_status = RQ_SCSI_BUSY; - scsi_do_req(sreq, cmnd, buffer, bufflen, scsi_wait_done, - timeout, retries); - wait_for_completion(&wait); - sreq->sr_request->waiting = NULL; - if (sreq->sr_request->rq_status != RQ_SCSI_DONE) - sreq->sr_result |= (DRIVER_ERROR << 24); - - __scsi_release_request(sreq); + struct request_queue *q = rq->q; + + bio->bi_flags &= ~(1 << BIO_SEG_VALID); + if (rq_data_dir(rq) == WRITE) + bio->bi_rw |= (1 << BIO_RW); + blk_queue_bounce(q, &bio); + + if (!rq->bio) + blk_rq_bio_prep(q, rq, bio); + else if (!ll_back_merge_fn(q, rq, bio)) + return -EINVAL; + else { + rq->biotail->bi_next = bio; + rq->biotail = bio; + } + + return 0; +} + +static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error) +{ + if (bio->bi_size) + return 1; + + bio_put(bio); + return 0; +} + +/** + * scsi_req_map_sg - map a scatterlist into a request + * @rq: request to fill + * @sg: scatterlist + * @nsegs: number of elements + * @bufflen: len of buffer + * @gfp: memory allocation flags + * + * scsi_req_map_sg maps a scatterlist into a request so that the + * request can be sent to the block layer. We do not trust the scatterlist + * sent to use, as some ULDs use that struct to only organize the pages. + */ +static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, + int nsegs, unsigned bufflen, gfp_t gfp) +{ + struct request_queue *q = rq->q; + int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT; + unsigned int data_len = 0, len, bytes, off; + struct page *page; + struct bio *bio = NULL; + int i, err, nr_vecs = 0; + + for (i = 0; i < nsegs; i++) { + page = sgl[i].page; + off = sgl[i].offset; + len = sgl[i].length; + data_len += len; + + while (len > 0) { + bytes = min_t(unsigned int, len, PAGE_SIZE - off); + + if (!bio) { + nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); + nr_pages -= nr_vecs; + + bio = bio_alloc(gfp, nr_vecs); + if (!bio) { + err = -ENOMEM; + goto free_bios; + } + bio->bi_end_io = scsi_bi_endio; + } + + if (bio_add_pc_page(q, bio, page, bytes, off) != + bytes) { + bio_put(bio); + err = -EINVAL; + goto free_bios; + } + + if (bio->bi_vcnt >= nr_vecs) { + err = scsi_merge_bio(rq, bio); + if (err) { + bio_endio(bio, bio->bi_size, 0); + goto free_bios; + } + bio = NULL; + } + + page++; + len -= bytes; + off = 0; + } + } + + rq->buffer = rq->data = NULL; + rq->data_len = data_len; + return 0; + +free_bios: + while ((bio = rq->bio) != NULL) { + rq->bio = bio->bi_next; + /* + * call endio instead of bio_put incase it was bounced + */ + bio_endio(bio, bio->bi_size, 0); + } + + return err; +} + +/** + * scsi_execute_async - insert request + * @sdev: scsi device + * @cmd: scsi command + * @cmd_len: length of scsi cdb + * @data_direction: data direction + * @buffer: data buffer (this can be a kernel buffer or scatterlist) + * @bufflen: len of buffer + * @use_sg: if buffer is a scatterlist this is the number of elements + * @timeout: request timeout in seconds + * @retries: number of times to retry request + * @flags: or into request flags + **/ +int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, + int cmd_len, int data_direction, void *buffer, unsigned bufflen, + int use_sg, int timeout, int retries, void *privdata, + void (*done)(void *, char *, int, int), gfp_t gfp) +{ + struct request *req; + struct scsi_io_context *sioc; + int err = 0; + int write = (data_direction == DMA_TO_DEVICE); + + sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); + if (!sioc) + return DRIVER_ERROR << 24; + memset(sioc, 0, sizeof(*sioc)); + + req = blk_get_request(sdev->request_queue, write, gfp); + if (!req) + goto free_sense; + req->cmd_type = REQ_TYPE_BLOCK_PC; + req->cmd_flags |= REQ_QUIET; + + if (use_sg) + err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); + else if (bufflen) + err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); + + if (err) + goto free_req; + + req->cmd_len = cmd_len; + memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */ + memcpy(req->cmd, cmd, req->cmd_len); + req->sense = sioc->sense; + req->sense_len = 0; + req->timeout = timeout; + req->retries = retries; + req->end_io_data = sioc; + + sioc->data = privdata; + sioc->done = done; + + blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); + return 0; + +free_req: + blk_put_request(req); +free_sense: + kmem_cache_free(scsi_io_context_cache, sioc); + return DRIVER_ERROR << 24; } +EXPORT_SYMBOL_GPL(scsi_execute_async); /* * Function: scsi_init_cmd_errh() @@ -274,65 +437,16 @@ void scsi_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer, * * Arguments: cmd - command that is ready to be queued. * - * Returns: Nothing - * * Notes: This function has the job of initializing a number of * fields related to error handling. Typically this will * be called once for each command, as required. */ -static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) +static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) { - cmd->owner = SCSI_OWNER_MIDLEVEL; cmd->serial_number = 0; - cmd->serial_number_at_timeout = 0; - cmd->abort_reason = 0; - memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); - if (cmd->cmd_len == 0) cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); - - /* - * We need saved copies of a number of fields - this is because - * error handling may need to overwrite these with different values - * to run different commands, and once error handling is complete, - * we will need to restore these values prior to running the actual - * command. - */ - cmd->old_use_sg = cmd->use_sg; - cmd->old_cmd_len = cmd->cmd_len; - cmd->sc_old_data_direction = cmd->sc_data_direction; - cmd->old_underflow = cmd->underflow; - memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); - cmd->buffer = cmd->request_buffer; - cmd->bufflen = cmd->request_bufflen; - cmd->internal_timeout = NORMAL_TIMEOUT; - cmd->abort_reason = 0; - - return 1; -} - -/* - * Function: scsi_setup_cmd_retry() - * - * Purpose: Restore the command state for a retry - * - * Arguments: cmd - command to be restored - * - * Returns: Nothing - * - * Notes: Immediately prior to retrying a command, we need - * to restore certain fields that we saved above. - */ -void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) -{ - memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); - cmd->request_buffer = cmd->buffer; - cmd->request_bufflen = cmd->bufflen; - cmd->use_sg = cmd->old_use_sg; - cmd->cmd_len = cmd->old_cmd_len; - cmd->sc_data_direction = cmd->sc_old_data_direction; - cmd->underflow = cmd->old_underflow; } void scsi_device_unbusy(struct scsi_device *sdev) @@ -342,13 +456,13 @@ void scsi_device_unbusy(struct scsi_device *sdev) spin_lock_irqsave(shost->host_lock, flags); shost->host_busy--; - if (unlikely(test_bit(SHOST_RECOVERY, &shost->shost_state) && - shost->host_failed)) + if (unlikely(scsi_host_in_recovery(shost) && + (shost->host_failed || shost->host_eh_scheduled))) scsi_eh_wakeup(shost); spin_unlock(shost->host_lock); - spin_lock(&sdev->sdev_lock); + spin_lock(sdev->request_queue->queue_lock); sdev->device_busy--; - spin_unlock_irqrestore(&sdev->sdev_lock, flags); + spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); } /* @@ -362,10 +476,11 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev) { struct Scsi_Host *shost = current_sdev->host; struct scsi_device *sdev, *tmp; + struct scsi_target *starget = scsi_target(current_sdev); unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); - current_sdev->sdev_target->starget_sdev_user = NULL; + starget->starget_sdev_user = NULL; spin_unlock_irqrestore(shost->host_lock, flags); /* @@ -377,10 +492,12 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev) blk_run_queue(current_sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); - if (current_sdev->sdev_target->starget_sdev_user) + if (starget->starget_sdev_user) goto out; - list_for_each_entry_safe(sdev, tmp, ¤t_sdev->same_target_siblings, + list_for_each_entry_safe(sdev, tmp, &starget->devices, same_target_siblings) { + if (sdev == current_sdev) + continue; if (scsi_device_get(sdev)) continue; @@ -435,7 +552,15 @@ static void scsi_run_queue(struct request_queue *q) list_del_init(&sdev->starved_entry); spin_unlock_irqrestore(shost->host_lock, flags); - blk_run_queue(sdev->request_queue); + + if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && + !test_and_set_bit(QUEUE_FLAG_REENTER, + &sdev->request_queue->queue_flags)) { + blk_run_queue(sdev->request_queue); + clear_bit(QUEUE_FLAG_REENTER, + &sdev->request_queue->queue_flags); + } else + blk_run_queue(sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); if (unlikely(!list_empty(&sdev->starved_entry))) @@ -467,21 +592,34 @@ static void scsi_run_queue(struct request_queue *q) * I/O errors in the middle of the request, in which case * we need to request the blocks that come after the bad * sector. + * Notes: Upon return, cmd is a stale pointer. */ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) { - cmd->request->flags &= ~REQ_DONTPREP; - blk_insert_request(q, cmd->request, 1, cmd, 1); + struct request *req = cmd->request; + unsigned long flags; + + scsi_unprep_request(req); + spin_lock_irqsave(q->queue_lock, flags); + blk_requeue_request(q, req); + spin_unlock_irqrestore(q->queue_lock, flags); scsi_run_queue(q); } void scsi_next_command(struct scsi_cmnd *cmd) { - struct request_queue *q = cmd->device->request_queue; + struct scsi_device *sdev = cmd->device; + struct request_queue *q = sdev->request_queue; + + /* need to hold a reference on the device before we let go of the cmd */ + get_device(&sdev->sdev_gendev); scsi_put_command(cmd); scsi_run_queue(q); + + /* ok to remove device now */ + put_device(&sdev->sdev_gendev); } void scsi_run_host_queues(struct Scsi_Host *shost) @@ -495,25 +633,24 @@ void scsi_run_host_queues(struct Scsi_Host *shost) /* * Function: scsi_end_request() * - * Purpose: Post-processing of completed commands called from interrupt - * handler or a bottom-half handler. + * Purpose: Post-processing of completed commands (usually invoked at end + * of upper level post-processing and scsi_io_completion). * * Arguments: cmd - command that is complete. - * uptodate - 1 if I/O indicates success, 0 for I/O error. - * sectors - number of sectors we want to mark. + * uptodate - 1 if I/O indicates success, <= 0 for I/O error. + * bytes - number of bytes of completed I/O * requeue - indicates whether we should requeue leftovers. - * frequeue - indicates that if we release the command block - * that the queue request function should be called. * * Lock status: Assumed that lock is not held upon entry. * - * Returns: Nothing + * Returns: cmd if requeue required, NULL otherwise. * * Notes: This is called for block device requests in order to * mark some number of sectors as complete. * * We are guaranteeing that the request queue will be goosed * at some point during this call. + * Notes: If cmd was requeued, upon return it will be a stale pointer. */ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, int bytes, int requeue) @@ -536,14 +673,15 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, if (!uptodate && blk_noretry_request(req)) end_that_request_chunk(req, 0, leftover); else { - if (requeue) + if (requeue) { /* * Bleah. Leftovers again. Stick the * leftovers in the front of the * queue, and goose the queue again. */ scsi_requeue_command(q, cmd); - + cmd = NULL; + } return cmd; } } @@ -553,7 +691,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, spin_lock_irqsave(q->queue_lock, flags); if (blk_rq_tagged(req)) blk_queue_end_tag(q, req); - end_that_request_last(req); + end_that_request_last(req, uptodate); spin_unlock_irqrestore(q->queue_lock, flags); /* @@ -564,7 +702,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, return NULL; } -static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, int gfp_mask) +struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) { struct scsi_host_sg_pool *sgp; struct scatterlist *sgl; @@ -602,21 +740,23 @@ static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, int gfp_mas sgp = scsi_sg_pools + cmd->sglist_len; sgl = mempool_alloc(sgp->pool, gfp_mask); - if (sgl) - memset(sgl, 0, sgp->size); return sgl; } -static void scsi_free_sgtable(struct scatterlist *sgl, int index) +EXPORT_SYMBOL(scsi_alloc_sgtable); + +void scsi_free_sgtable(struct scatterlist *sgl, int index) { struct scsi_host_sg_pool *sgp; - BUG_ON(index > SG_MEMPOOL_NR); + BUG_ON(index >= SG_MEMPOOL_NR); sgp = scsi_sg_pools + index; mempool_free(sgl, sgp->pool); } +EXPORT_SYMBOL(scsi_free_sgtable); + /* * Function: scsi_release_buffers() * @@ -636,22 +776,13 @@ static void scsi_free_sgtable(struct scatterlist *sgl, int index) */ static void scsi_release_buffers(struct scsi_cmnd *cmd) { - struct request *req = cmd->request; - - /* - * Free up any indirection buffers we allocated for DMA purposes. - */ if (cmd->use_sg) scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); - else if (cmd->request_buffer != req->buffer) - kfree(cmd->request_buffer); /* * Zero these out. They now point to freed memory, and it is * dangerous to hang onto the pointers. */ - cmd->buffer = NULL; - cmd->bufflen = 0; cmd->request_buffer = NULL; cmd->request_bufflen = 0; } @@ -684,38 +815,33 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd) * b) We can just use scsi_requeue_command() here. This would * be used if we just wanted to retry, for example. */ -void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, - unsigned int block_bytes) +void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) { int result = cmd->result; - int this_count = cmd->bufflen; + int this_count = cmd->request_bufflen; request_queue_t *q = cmd->device->request_queue; struct request *req = cmd->request; int clear_errors = 1; + struct scsi_sense_hdr sshdr; + int sense_valid = 0; + int sense_deferred = 0; - /* - * Free up any indirection buffers we allocated for DMA purposes. - * For the case of a READ, we need to copy the data out of the - * bounce buffer and into the real buffer. - */ - if (cmd->use_sg) - scsi_free_sgtable(cmd->buffer, cmd->sglist_len); - else if (cmd->buffer != req->buffer) { - if (rq_data_dir(req) == READ) { - unsigned long flags; - char *to = bio_kmap_irq(req->bio, &flags); - memcpy(to, cmd->buffer, cmd->bufflen); - bio_kunmap_irq(to, &flags); - } - kfree(cmd->buffer); + scsi_release_buffers(cmd); + + if (result) { + sense_valid = scsi_command_normalize_sense(cmd, &sshdr); + if (sense_valid) + sense_deferred = scsi_sense_is_deferred(&sshdr); } if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ - req->errors = (driver_byte(result) & DRIVER_SENSE) ? - (CHECK_CONDITION << 1) : (result & 0xff); + req->errors = result; if (result) { clear_errors = 0; - if (cmd->sense_buffer[0] & 0x70) { + if (sense_valid && req->sense) { + /* + * SG_IO wants current and deferred errors + */ int len = 8 + cmd->sense_buffer[7]; if (len > SCSI_SENSE_BUFFERSIZE) @@ -724,160 +850,135 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, req->sense_len = len; } } else - req->data_len -= cmd->bufflen; + req->data_len = cmd->resid; } - /* - * Zero these out. They now point to freed memory, and it is - * dangerous to hang onto the pointers. - */ - cmd->buffer = NULL; - cmd->bufflen = 0; - cmd->request_buffer = NULL; - cmd->request_bufflen = 0; - /* * Next deal with any sectors which we were able to correctly * handle. */ - if (good_bytes >= 0) { - SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", - req->nr_sectors, good_bytes)); - SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); + SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, " + "%d bytes done.\n", + req->nr_sectors, good_bytes)); + SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); - if (clear_errors) - req->errors = 0; - /* - * If multiple sectors are requested in one buffer, then - * they will have been finished off by the first command. - * If not, then we have a multi-buffer command. - * - * If block_bytes != 0, it means we had a medium error - * of some sort, and that we want to mark some number of - * sectors as not uptodate. Thus we want to inhibit - * requeueing right here - we will requeue down below - * when we handle the bad sectors. - */ - cmd = scsi_end_request(cmd, 1, good_bytes, result == 0); + if (clear_errors) + req->errors = 0; - /* - * If the command completed without error, then either finish off the - * rest of the command, or start a new one. - */ - if (result == 0 || cmd == NULL ) { - return; - } - } - /* - * Now, if we were good little boys and girls, Santa left us a request - * sense buffer. We can extract information from this, so we - * can choose a block to remap, etc. + /* A number of bytes were successfully read. If there + * are leftovers and there is some kind of error + * (result != 0), retry the rest. */ - if (driver_byte(result) != 0) { - if ((cmd->sense_buffer[0] & 0x7f) == 0x70) { - /* - * If the device is in the process of becoming ready, - * retry. - */ - if (cmd->sense_buffer[12] == 0x04 && - cmd->sense_buffer[13] == 0x01) { + if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) + return; + + /* good_bytes = 0, or (inclusive) there were leftovers and + * result = 0, so scsi_end_request couldn't retry. + */ + if (sense_valid && !sense_deferred) { + switch (sshdr.sense_key) { + case UNIT_ATTENTION: + if (cmd->device->removable) { + /* Detected disc change. Set a bit + * and quietly refuse further access. + */ + cmd->device->changed = 1; + scsi_end_request(cmd, 0, this_count, 1); + return; + } else { + /* Must have been a power glitch, or a + * bus reset. Could not have been a + * media change, so we just retry the + * request and see what happens. + */ scsi_requeue_command(q, cmd); return; } - if ((cmd->sense_buffer[2] & 0xf) == UNIT_ATTENTION) { - if (cmd->device->removable) { - /* detected disc change. set a bit - * and quietly refuse further access. - */ - cmd->device->changed = 1; - cmd = scsi_end_request(cmd, 0, - this_count, 1); - return; - } else { - /* - * Must have been a power glitch, or a - * bus reset. Could not have been a - * media change, so we just retry the - * request and see what happens. - */ - scsi_requeue_command(q, cmd); - return; - } - } - } - /* - * If we had an ILLEGAL REQUEST returned, then we may have - * performed an unsupported command. The only thing this - * should be would be a ten byte read where only a six byte - * read was supported. Also, on a system where READ CAPACITY - * failed, we may have read past the end of the disk. - */ - - switch (cmd->sense_buffer[2]) { + break; case ILLEGAL_REQUEST: - if (cmd->device->use_10_for_rw && + /* If we had an ILLEGAL REQUEST returned, then + * we may have performed an unsupported + * command. The only thing this should be + * would be a ten byte read where only a six + * byte read was supported. Also, on a system + * where READ CAPACITY failed, we may have + * read past the end of the disk. + */ + if ((cmd->device->use_10_for_rw && + sshdr.asc == 0x20 && sshdr.ascq == 0x00) && (cmd->cmnd[0] == READ_10 || cmd->cmnd[0] == WRITE_10)) { cmd->device->use_10_for_rw = 0; - /* - * This will cause a retry with a 6-byte - * command. + /* This will cause a retry with a + * 6-byte command. */ scsi_requeue_command(q, cmd); - result = 0; + return; } else { - cmd = scsi_end_request(cmd, 0, this_count, 1); + scsi_end_request(cmd, 0, this_count, 1); return; } break; case NOT_READY: - printk(KERN_INFO "Device %s not ready.\n", - req->rq_disk ? req->rq_disk->disk_name : ""); - cmd = scsi_end_request(cmd, 0, this_count, 1); + /* If the device is in the process of becoming + * ready, or has a temporary blockage, retry. + */ + if (sshdr.asc == 0x04) { + switch (sshdr.ascq) { + case 0x01: /* becoming ready */ + case 0x04: /* format in progress */ + case 0x05: /* rebuild in progress */ + case 0x06: /* recalculation in progress */ + case 0x07: /* operation in progress */ + case 0x08: /* Long write in progress */ + case 0x09: /* self test in progress */ + scsi_requeue_command(q, cmd); + return; + default: + break; + } + } + if (!(req->cmd_flags & REQ_QUIET)) { + scmd_printk(KERN_INFO, cmd, + "Device not ready: "); + scsi_print_sense_hdr("", &sshdr); + } + scsi_end_request(cmd, 0, this_count, 1); return; - break; - case MEDIUM_ERROR: case VOLUME_OVERFLOW: - printk("scsi%d: ERROR on channel %d, id %d, lun %d, CDB: ", - cmd->device->host->host_no, (int) cmd->device->channel, - (int) cmd->device->id, (int) cmd->device->lun); - __scsi_print_command(cmd->data_cmnd); - scsi_print_sense("", cmd); - cmd = scsi_end_request(cmd, 0, block_bytes, 1); + if (!(req->cmd_flags & REQ_QUIET)) { + scmd_printk(KERN_INFO, cmd, + "Volume overflow, CDB: "); + __scsi_print_command(cmd->cmnd); + scsi_print_sense("", cmd); + } + /* See SSC3rXX or current. */ + scsi_end_request(cmd, 0, this_count, 1); return; default: break; } - } /* driver byte != 0 */ + } if (host_byte(result) == DID_RESET) { - /* - * Third party bus reset or reset for error - * recovery reasons. Just retry the request - * and see what happens. + /* Third party bus reset or reset for error recovery + * reasons. Just retry the request and see what + * happens. */ scsi_requeue_command(q, cmd); return; } if (result) { - printk("SCSI error : <%d %d %d %d> return code = 0x%x\n", - cmd->device->host->host_no, - cmd->device->channel, - cmd->device->id, - cmd->device->lun, result); - - if (driver_byte(result) & DRIVER_SENSE) - scsi_print_sense("", cmd); - /* - * Mark a single buffer as not uptodate. Queue the remainder. - * We sometimes get this cruft in the event that a medium error - * isn't properly reported. - */ - block_bytes = req->hard_cur_sectors << 9; - if (!block_bytes) - block_bytes = req->data_len; - cmd = scsi_end_request(cmd, 0, block_bytes, 1); + if (!(req->cmd_flags & REQ_QUIET)) { + scmd_printk(KERN_INFO, cmd, + "SCSI error: return code = 0x%08x\n", + result); + if (driver_byte(result) & DRIVER_SENSE) + scsi_print_sense("", cmd); + } } + scsi_end_request(cmd, 0, this_count, !result); } +EXPORT_SYMBOL(scsi_io_completion); /* * Function: scsi_init_io() @@ -897,50 +998,36 @@ static int scsi_init_io(struct scsi_cmnd *cmd) int count; /* - * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer - */ - if ((req->flags & REQ_BLOCK_PC) && !req->bio) { - cmd->request_bufflen = req->data_len; - cmd->request_buffer = req->data; - req->buffer = req->data; - cmd->use_sg = 0; - return 0; - } - - /* - * we used to not use scatter-gather for single segment request, + * We used to not use scatter-gather for single segment request, * but now we do (it makes highmem I/O easier to support without * kmapping pages) */ cmd->use_sg = req->nr_phys_segments; /* - * if sg table allocation fails, requeue request later. + * If sg table allocation fails, requeue request later. */ sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); if (unlikely(!sgpnt)) { - req->flags |= REQ_SPECIAL; + scsi_unprep_request(req); return BLKPREP_DEFER; } + req->buffer = NULL; cmd->request_buffer = (char *) sgpnt; - cmd->request_bufflen = req->nr_sectors << 9; if (blk_pc_request(req)) cmd->request_bufflen = req->data_len; - req->buffer = NULL; + else + cmd->request_bufflen = req->nr_sectors << 9; /* * Next, walk the list, and fill in the addresses and sizes of * each segment. */ count = blk_rq_map_sg(req->q, req, cmd->request_buffer); - - /* - * mapped well, send it off - */ if (likely(count <= cmd->use_sg)) { cmd->use_sg = count; - return 0; + return BLKPREP_OK; } printk(KERN_ERR "Incorrect number of segments after building list\n"); @@ -954,148 +1041,233 @@ static int scsi_init_io(struct scsi_cmnd *cmd) return BLKPREP_KILL; } -static int scsi_prep_fn(struct request_queue *q, struct request *req) +static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, + sector_t *error_sector) { struct scsi_device *sdev = q->queuedata; - struct scsi_cmnd *cmd; - int specials_only = 0; + struct scsi_driver *drv; - /* - * Just check to see if the device is online. If it isn't, we - * refuse to process any commands. The device must be brought - * online before trying any recovery commands - */ - if (unlikely(!scsi_device_online(sdev))) { - printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to offline device\n", - sdev->host->host_no, sdev->id, sdev->lun); - return BLKPREP_KILL; - } - if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { - /* OK, we're not in a running state don't prep - * user commands */ - if (sdev->sdev_state == SDEV_DEL) { - /* Device is fully deleted, no commands - * at all allowed down */ - printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to dead device\n", - sdev->host->host_no, sdev->id, sdev->lun); - return BLKPREP_KILL; - } - /* OK, we only allow special commands (i.e. not - * user initiated ones */ - specials_only = sdev->sdev_state; - } + if (sdev->sdev_state != SDEV_RUNNING) + return -ENXIO; - /* - * Find the actual device driver associated with this command. - * The SPECIAL requests are things like character device or - * ioctls, which did not originate from ll_rw_blk. Note that - * the special field is also used to indicate the cmd for - * the remainder of a partially fulfilled request that can - * come up when there is a medium error. We have to treat - * these two cases differently. We differentiate by looking - * at request->cmd, as this tells us the real story. - */ - if (req->flags & REQ_SPECIAL) { - struct scsi_request *sreq = req->special; - - if (sreq->sr_magic == SCSI_REQ_MAGIC) { - cmd = scsi_get_command(sreq->sr_device, GFP_ATOMIC); - if (unlikely(!cmd)) - goto defer; - scsi_init_cmd_from_req(cmd, sreq); - } else - cmd = req->special; - } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { + drv = *(struct scsi_driver **) disk->private_data; + if (drv->issue_flush) + return drv->issue_flush(&sdev->sdev_gendev, error_sector); - if(unlikely(specials_only)) { - if(specials_only == SDEV_QUIESCE) - return BLKPREP_DEFER; - - printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to device being removed\n", - sdev->host->host_no, sdev->id, sdev->lun); - return BLKPREP_KILL; - } - - - /* - * Now try and find a command block that we can use. - */ - if (!req->special) { - cmd = scsi_get_command(sdev, GFP_ATOMIC); - if (unlikely(!cmd)) - goto defer; - } else - cmd = req->special; - - /* pull a tag out of the request if we have one */ - cmd->tag = req->tag; + return -EOPNOTSUPP; +} + +static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, + struct request *req) +{ + struct scsi_cmnd *cmd; + + if (!req->special) { + cmd = scsi_get_command(sdev, GFP_ATOMIC); + if (unlikely(!cmd)) + return NULL; + req->special = cmd; } else { - blk_dump_rq_flags(req, "SCSI bad req"); - return BLKPREP_KILL; + cmd = req->special; } - - /* note the overloading of req->special. When the tag - * is active it always means cmd. If the tag goes - * back for re-queueing, it may be reset */ - req->special = cmd; + + /* pull a tag out of the request if we have one */ + cmd->tag = req->tag; cmd->request = req; - + + return cmd; +} + +static void scsi_blk_pc_done(struct scsi_cmnd *cmd) +{ + BUG_ON(!blk_pc_request(cmd->request)); /* - * FIXME: drop the lock here because the functions below - * expect to be called without the queue lock held. Also, - * previously, we dequeued the request before dropping the - * lock. We hope REQ_STARTED prevents anything untoward from - * happening now. + * This will complete the whole command with uptodate=1 so + * as far as the block layer is concerned the command completed + * successfully. Since this is a REQ_BLOCK_PC command the + * caller should check the request's errors value */ - if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { - struct scsi_driver *drv; - int ret; + scsi_io_completion(cmd, cmd->request_bufflen); +} - /* - * This will do a couple of things: - * 1) Fill in the actual SCSI command. - * 2) Fill in any other upper-level specific fields - * (timeout). - * - * If this returns 0, it means that the request failed - * (reading past end of disk, reading offline device, - * etc). This won't actually talk to the device, but - * some kinds of consistency checking may cause the - * request to be rejected immediately. - */ +static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) +{ + struct scsi_cmnd *cmd; + + cmd = scsi_get_cmd_from_req(sdev, req); + if (unlikely(!cmd)) + return BLKPREP_DEFER; + + /* + * BLOCK_PC requests may transfer data, in which case they must + * a bio attached to them. Or they might contain a SCSI command + * that does not transfer data, in which case they may optionally + * submit a request without an attached bio. + */ + if (req->bio) { + int ret; + + BUG_ON(!req->nr_phys_segments); - /* - * This sets up the scatter-gather table (allocating if - * required). - */ ret = scsi_init_io(cmd); - if (ret) /* BLKPREP_KILL return also releases the command */ + if (unlikely(ret)) return ret; - - /* - * Initialize the actual SCSI command for this request. - */ - drv = *(struct scsi_driver **)req->rq_disk->private_data; - if (unlikely(!drv->init_command(cmd))) { - scsi_release_buffers(cmd); - scsi_put_command(cmd); - return BLKPREP_KILL; - } + } else { + BUG_ON(req->data_len); + BUG_ON(req->data); + + cmd->request_bufflen = 0; + cmd->request_buffer = NULL; + cmd->use_sg = 0; + req->buffer = NULL; } + BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); + memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); + cmd->cmd_len = req->cmd_len; + if (!req->data_len) + cmd->sc_data_direction = DMA_NONE; + else if (rq_data_dir(req) == WRITE) + cmd->sc_data_direction = DMA_TO_DEVICE; + else + cmd->sc_data_direction = DMA_FROM_DEVICE; + + cmd->transfersize = req->data_len; + cmd->allowed = req->retries; + cmd->timeout_per_command = req->timeout; + cmd->done = scsi_blk_pc_done; + return BLKPREP_OK; +} + +/* + * Setup a REQ_TYPE_FS command. These are simple read/write request + * from filesystems that still need to be translated to SCSI CDBs from + * the ULD. + */ +static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) +{ + struct scsi_cmnd *cmd; + struct scsi_driver *drv; + int ret; + + /* + * Filesystem requests must transfer data. + */ + BUG_ON(!req->nr_phys_segments); + + cmd = scsi_get_cmd_from_req(sdev, req); + if (unlikely(!cmd)) + return BLKPREP_DEFER; + + ret = scsi_init_io(cmd); + if (unlikely(ret)) + return ret; + /* - * The request is now prepped, no need to come back here + * Initialize the actual SCSI command for this request. */ - req->flags |= REQ_DONTPREP; + drv = *(struct scsi_driver **)req->rq_disk->private_data; + if (unlikely(!drv->init_command(cmd))) { + scsi_release_buffers(cmd); + scsi_put_command(cmd); + return BLKPREP_KILL; + } + return BLKPREP_OK; +} - defer: - /* If we defer, the elv_next_request() returns NULL, but the - * queue must be restarted, so we plug here if no returning - * command will automatically do that. */ - if (sdev->device_busy == 0) - blk_plug_device(q); - return BLKPREP_DEFER; +static int scsi_prep_fn(struct request_queue *q, struct request *req) +{ + struct scsi_device *sdev = q->queuedata; + int ret = BLKPREP_OK; + + /* + * If the device is not in running state we will reject some + * or all commands. + */ + if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { + switch (sdev->sdev_state) { + case SDEV_OFFLINE: + /* + * If the device is offline we refuse to process any + * commands. The device must be brought online + * before trying any recovery commands. + */ + sdev_printk(KERN_ERR, sdev, + "rejecting I/O to offline device\n"); + ret = BLKPREP_KILL; + break; + case SDEV_DEL: + /* + * If the device is fully deleted, we refuse to + * process any commands as well. + */ + sdev_printk(KERN_ERR, sdev, + "rejecting I/O to dead device\n"); + ret = BLKPREP_KILL; + break; + case SDEV_QUIESCE: + case SDEV_BLOCK: + /* + * If the devices is blocked we defer normal commands. + */ + if (!(req->cmd_flags & REQ_PREEMPT)) + ret = BLKPREP_DEFER; + break; + default: + /* + * For any other not fully online state we only allow + * special commands. In particular any user initiated + * command is not allowed. + */ + if (!(req->cmd_flags & REQ_PREEMPT)) + ret = BLKPREP_KILL; + break; + } + + if (ret != BLKPREP_OK) + goto out; + } + + switch (req->cmd_type) { + case REQ_TYPE_BLOCK_PC: + ret = scsi_setup_blk_pc_cmnd(sdev, req); + break; + case REQ_TYPE_FS: + ret = scsi_setup_fs_cmnd(sdev, req); + break; + default: + /* + * All other command types are not supported. + * + * Note that these days the SCSI subsystem does not use + * REQ_TYPE_SPECIAL requests anymore. These are only used + * (directly or via blk_insert_request) by non-SCSI drivers. + */ + blk_dump_rq_flags(req, "SCSI bad req"); + ret = BLKPREP_KILL; + break; + } + + out: + switch (ret) { + case BLKPREP_KILL: + req->errors = DID_NO_CONNECT << 16; + break; + case BLKPREP_DEFER: + /* + * If we defer, the elv_next_request() returns NULL, but the + * queue must be restarted, so we plug here if no returning + * command will automatically do that. + */ + if (sdev->device_busy == 0) + blk_plug_device(q); + break; + default: + req->cmd_flags |= REQ_DONTPREP; + } + + return ret; } /* @@ -1115,9 +1287,8 @@ static inline int scsi_dev_queue_ready(struct request_queue *q, */ if (--sdev->device_blocked == 0) { SCSI_LOG_MLQUEUE(3, - printk("scsi%d (%d:%d) unblocking device at" - " zero depth\n", sdev->host->host_no, - sdev->id, sdev->lun)); + sdev_printk(KERN_INFO, sdev, + "unblocking device at zero depth\n")); } else { blk_plug_device(q); return 0; @@ -1140,7 +1311,7 @@ static inline int scsi_host_queue_ready(struct request_queue *q, struct Scsi_Host *shost, struct scsi_device *sdev) { - if (test_bit(SHOST_RECOVERY, &shost->shost_state)) + if (scsi_host_in_recovery(shost)) return 0; if (shost->host_busy == 0 && shost->host_blocked) { /* @@ -1169,6 +1340,77 @@ static inline int scsi_host_queue_ready(struct request_queue *q, return 1; } +/* + * Kill a request for a dead device + */ +static void scsi_kill_request(struct request *req, request_queue_t *q) +{ + struct scsi_cmnd *cmd = req->special; + struct scsi_device *sdev = cmd->device; + struct Scsi_Host *shost = sdev->host; + + blkdev_dequeue_request(req); + + if (unlikely(cmd == NULL)) { + printk(KERN_CRIT "impossible request in %s.\n", + __FUNCTION__); + BUG(); + } + + scsi_init_cmd_errh(cmd); + cmd->result = DID_NO_CONNECT << 16; + atomic_inc(&cmd->device->iorequest_cnt); + + /* + * SCSI request completion path will do scsi_device_unbusy(), + * bump busy counts. To bump the counters, we need to dance + * with the locks as normal issue path does. + */ + sdev->device_busy++; + spin_unlock(sdev->request_queue->queue_lock); + spin_lock(shost->host_lock); + shost->host_busy++; + spin_unlock(shost->host_lock); + spin_lock(sdev->request_queue->queue_lock); + + __scsi_done(cmd); +} + +static void scsi_softirq_done(struct request *rq) +{ + struct scsi_cmnd *cmd = rq->completion_data; + unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; + int disposition; + + INIT_LIST_HEAD(&cmd->eh_entry); + + disposition = scsi_decide_disposition(cmd); + if (disposition != SUCCESS && + time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { + sdev_printk(KERN_ERR, cmd->device, + "timing out command, waited %lus\n", + wait_for/HZ); + disposition = SUCCESS; + } + + scsi_log_completion(cmd, disposition); + + switch (disposition) { + case SUCCESS: + scsi_finish_command(cmd); + break; + case NEEDS_RETRY: + scsi_retry_command(cmd); + break; + case ADD_TO_MLQUEUE: + scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); + break; + default: + if (!scsi_eh_scmd_add(cmd, 0)) + scsi_finish_command(cmd); + } +} + /* * Function: scsi_request_fn() * @@ -1183,10 +1425,17 @@ static inline int scsi_host_queue_ready(struct request_queue *q, static void scsi_request_fn(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; - struct Scsi_Host *shost = sdev->host; + struct Scsi_Host *shost; struct scsi_cmnd *cmd; struct request *req; + if (!sdev) { + printk("scsi: killing requests for dead queue\n"); + while ((req = elv_next_request(q)) != NULL) + scsi_kill_request(req, q); + return; + } + if(!get_device(&sdev->sdev_gendev)) /* We must be tearing the block queue down already */ return; @@ -1195,6 +1444,7 @@ static void scsi_request_fn(struct request_queue *q) * To start with, we keep looping until the queue is empty, or until * the host is no longer able to accept any more requests. */ + shost = sdev->host; while (!blk_queue_plugged(q)) { int rtn; /* @@ -1207,13 +1457,9 @@ static void scsi_request_fn(struct request_queue *q) break; if (unlikely(!scsi_device_online(sdev))) { - printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to offline device\n", - sdev->host->host_no, sdev->id, sdev->lun); - blkdev_dequeue_request(req); - req->flags |= REQ_QUIET; - while (end_that_request_first(req, 0, req->nr_sectors)) - ; - end_that_request_last(req); + sdev_printk(KERN_ERR, sdev, + "rejecting I/O to offline device\n"); + scsi_kill_request(req, q); continue; } @@ -1226,15 +1472,24 @@ static void scsi_request_fn(struct request_queue *q) sdev->device_busy++; spin_unlock(q->queue_lock); + cmd = req->special; + if (unlikely(cmd == NULL)) { + printk(KERN_CRIT "impossible request in %s.\n" + "please mail a stack trace to " + "linux-scsi@vger.kernel.org\n", + __FUNCTION__); + blk_dump_rq_flags(req, "foo"); + BUG(); + } spin_lock(shost->host_lock); if (!scsi_host_queue_ready(q, shost, sdev)) goto not_ready; if (sdev->single_lun) { - if (sdev->sdev_target->starget_sdev_user && - sdev->sdev_target->starget_sdev_user != sdev) + if (scsi_target(sdev)->starget_sdev_user && + scsi_target(sdev)->starget_sdev_user != sdev) goto not_ready; - sdev->sdev_target->starget_sdev_user = sdev; + scsi_target(sdev)->starget_sdev_user = sdev; } shost->host_busy++; @@ -1244,15 +1499,6 @@ static void scsi_request_fn(struct request_queue *q) */ spin_unlock_irq(shost->host_lock); - cmd = req->special; - if (unlikely(cmd == NULL)) { - printk(KERN_CRIT "impossible request in %s.\n" - "please mail a stack trace to " - "linux-scsi@vger.kernel.org", - __FUNCTION__); - BUG(); - } - /* * Finally, initialize any error handling parameters, and set up * the timers for timeouts. @@ -1304,42 +1550,59 @@ static void scsi_request_fn(struct request_queue *q) u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) { struct device *host_dev; + u64 bounce_limit = 0xffffffff; if (shost->unchecked_isa_dma) return BLK_BOUNCE_ISA; - - host_dev = scsi_get_device(shost); - if (PCI_DMA_BUS_IS_PHYS && host_dev && host_dev->dma_mask) - return *host_dev->dma_mask; - /* * Platforms with virtual-DMA translation * hardware have no practical limit. */ - return BLK_BOUNCE_ANY; + if (!PCI_DMA_BUS_IS_PHYS) + return BLK_BOUNCE_ANY; + + host_dev = scsi_get_device(shost); + if (host_dev && host_dev->dma_mask) + bounce_limit = *host_dev->dma_mask; + + return bounce_limit; } +EXPORT_SYMBOL(scsi_calculate_bounce_limit); -struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) +struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, + request_fn_proc *request_fn) { - struct Scsi_Host *shost = sdev->host; struct request_queue *q; - q = blk_init_queue(scsi_request_fn, &sdev->sdev_lock); + q = blk_init_queue(request_fn, NULL); if (!q) return NULL; - blk_queue_prep_rq(q, scsi_prep_fn); - blk_queue_max_hw_segments(q, shost->sg_tablesize); blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); blk_queue_max_sectors(q, shost->max_sectors); blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); blk_queue_segment_boundary(q, shost->dma_boundary); - + if (!shost->use_clustering) clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); return q; } +EXPORT_SYMBOL(__scsi_alloc_queue); + +struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) +{ + struct request_queue *q; + + q = __scsi_alloc_queue(sdev->host, scsi_request_fn); + if (!q) + return NULL; + + blk_queue_prep_rq(q, scsi_prep_fn); + blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); + blk_queue_softirq_done(q, scsi_softirq_done); + return q; +} void scsi_free_queue(struct request_queue *q) { @@ -1366,6 +1629,7 @@ void scsi_block_requests(struct Scsi_Host *shost) { shost->host_self_blocked = 1; } +EXPORT_SYMBOL(scsi_block_requests); /* * Function: scsi_unblock_requests() @@ -1392,11 +1656,20 @@ void scsi_unblock_requests(struct Scsi_Host *shost) shost->host_self_blocked = 0; scsi_run_host_queues(shost); } +EXPORT_SYMBOL(scsi_unblock_requests); int __init scsi_init_queue(void) { int i; + scsi_io_context_cache = kmem_cache_create("scsi_io_context", + sizeof(struct scsi_io_context), + 0, 0, NULL, NULL); + if (!scsi_io_context_cache) { + printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); + return -ENOMEM; + } + for (i = 0; i < SG_MEMPOOL_NR; i++) { struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; int size = sgp->size * sizeof(struct scatterlist); @@ -1408,9 +1681,8 @@ int __init scsi_init_queue(void) sgp->name); } - sgp->pool = mempool_create(SG_MEMPOOL_SIZE, - mempool_alloc_slab, mempool_free_slab, - sgp->slab); + sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, + sgp->slab); if (!sgp->pool) { printk(KERN_ERR "SCSI: can't init sg mempool %s\n", sgp->name); @@ -1424,16 +1696,96 @@ void scsi_exit_queue(void) { int i; + kmem_cache_destroy(scsi_io_context_cache); + for (i = 0; i < SG_MEMPOOL_NR; i++) { struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; mempool_destroy(sgp->pool); kmem_cache_destroy(sgp->slab); } } + +/** + * scsi_mode_select - issue a mode select + * @sdev: SCSI device to be queried + * @pf: Page format bit (1 == standard, 0 == vendor specific) + * @sp: Save page bit (0 == don't save, 1 == save) + * @modepage: mode page being requested + * @buffer: request buffer (may not be smaller than eight bytes) + * @len: length of request buffer. + * @timeout: command timeout + * @retries: number of retries before failing + * @data: returns a structure abstracting the mode header data + * @sense: place to put sense data (or NULL if no sense to be collected). + * must be SCSI_SENSE_BUFFERSIZE big. + * + * Returns zero if successful; negative error number or scsi + * status on error + * + */ +int +scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, + unsigned char *buffer, int len, int timeout, int retries, + struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) +{ + unsigned char cmd[10]; + unsigned char *real_buffer; + int ret; + + memset(cmd, 0, sizeof(cmd)); + cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); + + if (sdev->use_10_for_ms) { + if (len > 65535) + return -EINVAL; + real_buffer = kmalloc(8 + len, GFP_KERNEL); + if (!real_buffer) + return -ENOMEM; + memcpy(real_buffer + 8, buffer, len); + len += 8; + real_buffer[0] = 0; + real_buffer[1] = 0; + real_buffer[2] = data->medium_type; + real_buffer[3] = data->device_specific; + real_buffer[4] = data->longlba ? 0x01 : 0; + real_buffer[5] = 0; + real_buffer[6] = data->block_descriptor_length >> 8; + real_buffer[7] = data->block_descriptor_length; + + cmd[0] = MODE_SELECT_10; + cmd[7] = len >> 8; + cmd[8] = len; + } else { + if (len > 255 || data->block_descriptor_length > 255 || + data->longlba) + return -EINVAL; + + real_buffer = kmalloc(4 + len, GFP_KERNEL); + if (!real_buffer) + return -ENOMEM; + memcpy(real_buffer + 4, buffer, len); + len += 4; + real_buffer[0] = 0; + real_buffer[1] = data->medium_type; + real_buffer[2] = data->device_specific; + real_buffer[3] = data->block_descriptor_length; + + + cmd[0] = MODE_SELECT; + cmd[4] = len; + } + + ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, + sshdr, timeout, retries); + kfree(real_buffer); + return ret; +} +EXPORT_SYMBOL_GPL(scsi_mode_select); + /** - * __scsi_mode_sense - issue a mode sense, falling back from 10 to + * scsi_mode_sense - issue a mode sense, falling back from 10 to * six bytes if necessary. - * @sreq: SCSI request to fill in with the MODE_SENSE + * @sdev: SCSI device to be queried * @dbd: set if mode sense will allow block descriptors to be returned * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) @@ -1441,26 +1793,35 @@ void scsi_exit_queue(void) * @timeout: command timeout * @retries: number of retries before failing * @data: returns a structure abstracting the mode header data + * @sense: place to put sense data (or NULL if no sense to be collected). + * must be SCSI_SENSE_BUFFERSIZE big. * * Returns zero if unsuccessful, or the header offset (either 4 * or 8 depending on whether a six or ten byte command was * issued) if successful. **/ int -__scsi_mode_sense(struct scsi_request *sreq, int dbd, int modepage, +scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, unsigned char *buffer, int len, int timeout, int retries, - struct scsi_mode_data *data) { + struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) +{ unsigned char cmd[12]; int use_10_for_ms; int header_length; + int result; + struct scsi_sense_hdr my_sshdr; memset(data, 0, sizeof(*data)); memset(&cmd[0], 0, 12); cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ cmd[2] = modepage; + /* caller might not be interested in sense, but we need it */ + if (!sshdr) + sshdr = &my_sshdr; + retry: - use_10_for_ms = sreq->sr_device->use_10_for_ms; + use_10_for_ms = sdev->use_10_for_ms; if (use_10_for_ms) { if (len < 8) @@ -1478,32 +1839,41 @@ __scsi_mode_sense(struct scsi_request *sreq, int dbd, int modepage, header_length = 4; } - sreq->sr_cmd_len = 0; - sreq->sr_sense_buffer[0] = 0; - sreq->sr_sense_buffer[2] = 0; - sreq->sr_data_direction = DMA_FROM_DEVICE; - memset(buffer, 0, len); - scsi_wait_req(sreq, cmd, buffer, len, timeout, retries); + result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, + sshdr, timeout, retries); /* This code looks awful: what it's doing is making sure an * ILLEGAL REQUEST sense return identifies the actual command * byte as the problem. MODE_SENSE commands can return * ILLEGAL REQUEST if the code page isn't supported */ - if (use_10_for_ms && ! scsi_status_is_good(sreq->sr_result) && - (driver_byte(sreq->sr_result) & DRIVER_SENSE) && - sreq->sr_sense_buffer[2] == ILLEGAL_REQUEST && - (sreq->sr_sense_buffer[4] & 0x40) == 0x40 && - sreq->sr_sense_buffer[5] == 0 && - sreq->sr_sense_buffer[6] == 0 ) { - sreq->sr_device->use_10_for_ms = 0; - goto retry; + + if (use_10_for_ms && !scsi_status_is_good(result) && + (driver_byte(result) & DRIVER_SENSE)) { + if (scsi_sense_valid(sshdr)) { + if ((sshdr->sense_key == ILLEGAL_REQUEST) && + (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { + /* + * Invalid command operation code + */ + sdev->use_10_for_ms = 0; + goto retry; + } + } } - if(scsi_status_is_good(sreq->sr_result)) { - data->header_length = header_length; - if(use_10_for_ms) { + if(scsi_status_is_good(result)) { + if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && + (modepage == 6 || modepage == 8))) { + /* Initio breakage? */ + header_length = 0; + data->length = 13; + data->medium_type = 0; + data->device_specific = 0; + data->longlba = 0; + data->block_descriptor_length = 0; + } else if(use_10_for_ms) { data->length = buffer[0]*256 + buffer[1] + 2; data->medium_type = buffer[2]; data->device_specific = buffer[3]; @@ -1516,44 +1886,37 @@ __scsi_mode_sense(struct scsi_request *sreq, int dbd, int modepage, data->device_specific = buffer[2]; data->block_descriptor_length = buffer[3]; } + data->header_length = header_length; } - return sreq->sr_result; + return result; } +EXPORT_SYMBOL(scsi_mode_sense); -/** - * scsi_mode_sense - issue a mode sense, falling back from 10 to - * six bytes if necessary. - * @sdev: scsi device to send command to. - * @dbd: set if mode sense will disable block descriptors in the return - * @modepage: mode page being requested - * @buffer: request buffer (may not be smaller than eight bytes) - * @len: length of request buffer. - * @timeout: command timeout - * @retries: number of retries before failing - * - * Returns zero if unsuccessful, or the header offset (either 4 - * or 8 depending on whether a six or ten byte command was - * issued) if successful. - **/ int -scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, - unsigned char *buffer, int len, int timeout, int retries, - struct scsi_mode_data *data) +scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) { - struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL); - int ret; - - if (!sreq) - return -1; - - ret = __scsi_mode_sense(sreq, dbd, modepage, buffer, len, - timeout, retries, data); + char cmd[] = { + TEST_UNIT_READY, 0, 0, 0, 0, 0, + }; + struct scsi_sense_hdr sshdr; + int result; + + result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, + timeout, retries); - scsi_release_request(sreq); + if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { - return ret; + if ((scsi_sense_valid(&sshdr)) && + ((sshdr.sense_key == UNIT_ATTENTION) || + (sshdr.sense_key == NOT_READY))) { + sdev->changed = 1; + result = 0; + } + } + return result; } +EXPORT_SYMBOL(scsi_test_unit_ready); /** * scsi_device_set_state - Take the given device through the device @@ -1584,6 +1947,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) case SDEV_CREATED: case SDEV_OFFLINE: case SDEV_QUIESCE: + case SDEV_BLOCK: break; default: goto illegal; @@ -1605,6 +1969,17 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) case SDEV_CREATED: case SDEV_RUNNING: case SDEV_QUIESCE: + case SDEV_BLOCK: + break; + default: + goto illegal; + } + break; + + case SDEV_BLOCK: + switch (oldstate) { + case SDEV_CREATED: + case SDEV_RUNNING: break; default: goto illegal; @@ -1615,7 +1990,9 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: + case SDEV_QUIESCE: case SDEV_OFFLINE: + case SDEV_BLOCK: break; default: goto illegal; @@ -1624,6 +2001,9 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) case SDEV_DEL: switch (oldstate) { + case SDEV_CREATED: + case SDEV_RUNNING: + case SDEV_OFFLINE: case SDEV_CANCEL: break; default: @@ -1636,11 +2016,12 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) return 0; illegal: - dev_printk(KERN_ERR, &sdev->sdev_gendev, - "Illegal state transition %s->%s\n", - scsi_device_state_name(oldstate), - scsi_device_state_name(state)); - WARN_ON(1); + SCSI_LOG_ERROR_RECOVERY(1, + sdev_printk(KERN_ERR, sdev, + "Illegal state transition %s->%s\n", + scsi_device_state_name(oldstate), + scsi_device_state_name(state)) + ); return -EINVAL; } EXPORT_SYMBOL(scsi_device_set_state); @@ -1669,7 +2050,7 @@ scsi_device_quiesce(struct scsi_device *sdev) scsi_run_queue(sdev->request_queue); while (sdev->device_busy) { - schedule_timeout(HZ/5); + msleep_interruptible(200); scsi_run_queue(sdev->request_queue); } return 0; @@ -1694,3 +2075,219 @@ scsi_device_resume(struct scsi_device *sdev) } EXPORT_SYMBOL(scsi_device_resume); +static void +device_quiesce_fn(struct scsi_device *sdev, void *data) +{ + scsi_device_quiesce(sdev); +} + +void +scsi_target_quiesce(struct scsi_target *starget) +{ + starget_for_each_device(starget, NULL, device_quiesce_fn); +} +EXPORT_SYMBOL(scsi_target_quiesce); + +static void +device_resume_fn(struct scsi_device *sdev, void *data) +{ + scsi_device_resume(sdev); +} + +void +scsi_target_resume(struct scsi_target *starget) +{ + starget_for_each_device(starget, NULL, device_resume_fn); +} +EXPORT_SYMBOL(scsi_target_resume); + +/** + * scsi_internal_device_block - internal function to put a device + * temporarily into the SDEV_BLOCK state + * @sdev: device to block + * + * Block request made by scsi lld's to temporarily stop all + * scsi commands on the specified device. Called from interrupt + * or normal process context. + * + * Returns zero if successful or error if not + * + * Notes: + * This routine transitions the device to the SDEV_BLOCK state + * (which must be a legal transition). When the device is in this + * state, all commands are deferred until the scsi lld reenables + * the device with scsi_device_unblock or device_block_tmo fires. + * This routine assumes the host_lock is held on entry. + **/ +int +scsi_internal_device_block(struct scsi_device *sdev) +{ + request_queue_t *q = sdev->request_queue; + unsigned long flags; + int err = 0; + + err = scsi_device_set_state(sdev, SDEV_BLOCK); + if (err) + return err; + + /* + * The device has transitioned to SDEV_BLOCK. Stop the + * block layer from calling the midlayer with this device's + * request queue. + */ + spin_lock_irqsave(q->queue_lock, flags); + blk_stop_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(scsi_internal_device_block); + +/** + * scsi_internal_device_unblock - resume a device after a block request + * @sdev: device to resume + * + * Called by scsi lld's or the midlayer to restart the device queue + * for the previously suspended scsi device. Called from interrupt or + * normal process context. + * + * Returns zero if successful or error if not. + * + * Notes: + * This routine transitions the device to the SDEV_RUNNING state + * (which must be a legal transition) allowing the midlayer to + * goose the queue for this device. This routine assumes the + * host_lock is held upon entry. + **/ +int +scsi_internal_device_unblock(struct scsi_device *sdev) +{ + request_queue_t *q = sdev->request_queue; + int err; + unsigned long flags; + + /* + * Try to transition the scsi device to SDEV_RUNNING + * and goose the device queue if successful. + */ + err = scsi_device_set_state(sdev, SDEV_RUNNING); + if (err) + return err; + + spin_lock_irqsave(q->queue_lock, flags); + blk_start_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); + +static void +device_block(struct scsi_device *sdev, void *data) +{ + scsi_internal_device_block(sdev); +} + +static int +target_block(struct device *dev, void *data) +{ + if (scsi_is_target_device(dev)) + starget_for_each_device(to_scsi_target(dev), NULL, + device_block); + return 0; +} + +void +scsi_target_block(struct device *dev) +{ + if (scsi_is_target_device(dev)) + starget_for_each_device(to_scsi_target(dev), NULL, + device_block); + else + device_for_each_child(dev, NULL, target_block); +} +EXPORT_SYMBOL_GPL(scsi_target_block); + +static void +device_unblock(struct scsi_device *sdev, void *data) +{ + scsi_internal_device_unblock(sdev); +} + +static int +target_unblock(struct device *dev, void *data) +{ + if (scsi_is_target_device(dev)) + starget_for_each_device(to_scsi_target(dev), NULL, + device_unblock); + return 0; +} + +void +scsi_target_unblock(struct device *dev) +{ + if (scsi_is_target_device(dev)) + starget_for_each_device(to_scsi_target(dev), NULL, + device_unblock); + else + device_for_each_child(dev, NULL, target_unblock); +} +EXPORT_SYMBOL_GPL(scsi_target_unblock); + +/** + * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt + * @sg: scatter-gather list + * @sg_count: number of segments in sg + * @offset: offset in bytes into sg, on return offset into the mapped area + * @len: bytes to map, on return number of bytes mapped + * + * Returns virtual address of the start of the mapped page + */ +void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count, + size_t *offset, size_t *len) +{ + int i; + size_t sg_len = 0, len_complete = 0; + struct page *page; + + for (i = 0; i < sg_count; i++) { + len_complete = sg_len; /* Complete sg-entries */ + sg_len += sg[i].length; + if (sg_len > *offset) + break; + } + + if (unlikely(i == sg_count)) { + printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " + "elements %d\n", + __FUNCTION__, sg_len, *offset, sg_count); + WARN_ON(1); + return NULL; + } + + /* Offset starting from the beginning of first page in this sg-entry */ + *offset = *offset - len_complete + sg[i].offset; + + /* Assumption: contiguous pages can be accessed as "page + i" */ + page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT)); + *offset &= ~PAGE_MASK; + + /* Bytes in this sg-entry from *offset to the end of the page */ + sg_len = PAGE_SIZE - *offset; + if (*len > sg_len) + *len = sg_len; + + return kmap_atomic(page, KM_BIO_SRC_IRQ); +} +EXPORT_SYMBOL(scsi_kmap_atomic_sg); + +/** + * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously + * mapped with scsi_kmap_atomic_sg + * @virt: virtual address to be unmapped + */ +void scsi_kunmap_atomic_sg(void *virt) +{ + kunmap_atomic(virt, KM_BIO_SRC_IRQ); +} +EXPORT_SYMBOL(scsi_kunmap_atomic_sg);