X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fscsi%2Fscsi_lib.c;h=f02f48a882a97b4150a7afe9eb403f1ce7f293fb;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=faee4757c03adb712363eb09527c5af357c0bef3;hpb=43bc926fffd92024b46cafaf7350d669ba9ca884;p=linux-2.6.git diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index faee4757c..f02f48a88 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -19,24 +19,24 @@ #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; }; @@ -82,8 +82,8 @@ static void scsi_unprep_request(struct request *req) { struct scsi_cmnd *cmd = req->special; - req->flags &= ~REQ_DONTPREP; - req->special = (req->flags & REQ_SPECIAL) ? cmd->sc_request : NULL; + req->cmd_flags &= ~REQ_DONTPREP; + req->special = NULL; scsi_put_command(cmd); } @@ -161,72 +161,6 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) 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) -{ - /* - * 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); - - /* - * 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; - - if (sreq->sr_cmd_len == 0) - sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); - - /* - * head injection *required* here otherwise quiesce won't work - * - * 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, - 1, sreq); -} -EXPORT_SYMBOL(scsi_do_req); - /** * scsi_execute - insert request and wait for the result * @sdev: scsi device @@ -262,7 +196,8 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, req->sense_len = 0; req->retries = retries; req->timeout = timeout; - req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET; + req->cmd_type = REQ_TYPE_BLOCK_PC; + req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; /* * head injection *required* here otherwise quiesce won't work @@ -306,7 +241,7 @@ struct scsi_io_context { char sense[SCSI_SENSE_BUFFERSIZE]; }; -static kmem_cache_t *scsi_io_context_cache; +static struct kmem_cache *scsi_io_context_cache; static void scsi_end_async(struct request *req, int uptodate) { @@ -330,13 +265,11 @@ static int scsi_merge_bio(struct request *rq, struct bio *bio) if (!rq->bio) blk_rq_bio_prep(q, rq, bio); - else if (!q->back_merge_fn(q, rq, bio)) + else if (!ll_back_merge_fn(q, rq, bio)) return -EINVAL; else { rq->biotail->bi_next = bio; rq->biotail = bio; - rq->hard_nr_sectors += bio_sectors(bio); - rq->nr_sectors = rq->hard_nr_sectors; } return 0; @@ -463,7 +396,8 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, req = blk_get_request(sdev->request_queue, write, gfp); if (!req) goto free_sense; - req->flags |= REQ_BLOCK_PC | REQ_QUIET; + 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); @@ -474,6 +408,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, 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; @@ -490,7 +425,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, free_req: blk_put_request(req); free_sense: - kfree(sioc); + kmem_cache_free(scsi_io_context_cache, sioc); return DRIVER_ERROR << 24; } EXPORT_SYMBOL_GPL(scsi_execute_async); @@ -502,60 +437,16 @@ EXPORT_SYMBOL_GPL(scsi_execute_async); * * 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->serial_number = 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; - - 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) @@ -566,7 +457,7 @@ void scsi_device_unbusy(struct scsi_device *sdev) spin_lock_irqsave(shost->host_lock, flags); shost->host_busy--; if (unlikely(scsi_host_in_recovery(shost) && - shost->host_failed)) + (shost->host_failed || shost->host_eh_scheduled))) scsi_eh_wakeup(shost); spin_unlock(shost->host_lock); spin_lock(sdev->request_queue->queue_lock); @@ -661,7 +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))) @@ -803,7 +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, gfp_t gfp_mask) +struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) { struct scsi_host_sg_pool *sgp; struct scatterlist *sgl; @@ -844,7 +743,9 @@ static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_m 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; @@ -854,6 +755,8 @@ static void scsi_free_sgtable(struct scatterlist *sgl, int index) mempool_free(sgl, sgp->pool); } +EXPORT_SYMBOL(scsi_free_sgtable); + /* * Function: scsi_release_buffers() * @@ -873,22 +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; } @@ -921,11 +815,10 @@ 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; @@ -933,28 +826,14 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, 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 = result; if (result) { @@ -974,100 +853,74 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, 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. - */ + 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 (scsi_end_request(cmd, 1, good_bytes, result == 0) == 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 (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 + /* Detected disc change. Set a bit * and quietly refuse further access. */ cmd->device->changed = 1; - scsi_end_request(cmd, 0, - this_count, 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. - */ + /* 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; } break; case ILLEGAL_REQUEST: - /* - * 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 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 { scsi_end_request(cmd, 0, this_count, 1); return; } break; case NOT_READY: - /* - * If the device is in the process of becoming + /* If the device is in the process of becoming * ready, or has a temporary blockage, retry. */ if (sshdr.asc == 0x04) { @@ -1085,53 +938,45 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, break; } } - if (!(req->flags & REQ_QUIET)) { + if (!(req->cmd_flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "Device not ready: "); + "Device not ready: "); scsi_print_sense_hdr("", &sshdr); } scsi_end_request(cmd, 0, this_count, 1); return; case VOLUME_OVERFLOW: - if (!(req->flags & REQ_QUIET)) { + if (!(req->cmd_flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "Volume overflow, CDB: "); - __scsi_print_command(cmd->data_cmnd); + "Volume overflow, CDB: "); + __scsi_print_command(cmd->cmnd); scsi_print_sense("", cmd); } - scsi_end_request(cmd, 0, block_bytes, 1); + /* 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) { - if (!(req->flags & REQ_QUIET)) { + if (!(req->cmd_flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "SCSI error: return code = 0x%x\n", result); - + "SCSI error: return code = 0x%08x\n", + 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; - scsi_end_request(cmd, 0, block_bytes, 1); } + scsi_end_request(cmd, 0, this_count, !result); } EXPORT_SYMBOL(scsi_io_completion); @@ -1153,25 +998,14 @@ 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)) { @@ -1179,24 +1013,21 @@ static int scsi_init_io(struct scsi_cmnd *cmd) 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"); @@ -1226,6 +1057,27 @@ static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, 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 { + cmd = req->special; + } + + /* 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)); @@ -1235,14 +1087,42 @@ static void scsi_blk_pc_done(struct scsi_cmnd *cmd) * successfully. Since this is a REQ_BLOCK_PC command the * caller should check the request's errors value */ - scsi_io_completion(cmd, cmd->bufflen, 0); + scsi_io_completion(cmd, cmd->request_bufflen); } -static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) +static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) { - struct request *req = cmd->request; + 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); - BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); + ret = scsi_init_io(cmd); + if (unlikely(ret)) + return ret; + } 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) @@ -1256,164 +1136,138 @@ static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) cmd->allowed = req->retries; cmd->timeout_per_command = req->timeout; cmd->done = scsi_blk_pc_done; + return BLKPREP_OK; } -static int scsi_prep_fn(struct request_queue *q, struct request *req) +/* + * 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_device *sdev = q->queuedata; struct scsi_cmnd *cmd; - int specials_only = 0; + struct scsi_driver *drv; + int ret; /* - * 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 + * Filesystem requests must transfer data. */ - if (unlikely(!scsi_device_online(sdev))) { - sdev_printk(KERN_ERR, sdev, - "rejecting I/O to offline device\n"); - goto 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 */ - sdev_printk(KERN_ERR, sdev, - "rejecting I/O to dead device\n"); - goto kill; - } - /* OK, we only allow special commands (i.e. not - * user initiated ones */ - specials_only = sdev->sdev_state; - } + 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; /* - * 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. + * Initialize the actual SCSI command for this request. */ - if (req->flags & REQ_SPECIAL && 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 **)req->rq_disk->private_data; + if (unlikely(!drv->init_command(cmd))) { + scsi_release_buffers(cmd); + scsi_put_command(cmd); + return BLKPREP_KILL; + } - if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { - if(specials_only == SDEV_QUIESCE || - specials_only == SDEV_BLOCK) - goto defer; - + return BLKPREP_OK; +} + +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 device being removed\n"); - goto kill; + "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; } - - - /* - * 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; - } else { - blk_dump_rq_flags(req, "SCSI bad req"); - goto kill; + + if (ret != BLKPREP_OK) + goto out; } - - /* 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; - cmd->request = req; - - /* - * 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. - */ - if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { - int ret; + 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: /* - * This will do a couple of things: - * 1) Fill in the actual SCSI command. - * 2) Fill in any other upper-level specific fields - * (timeout). + * All other command types are not supported. * - * 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. + * 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; + } - /* - * This sets up the scatter-gather table (allocating if - * required). - */ - ret = scsi_init_io(cmd); - switch(ret) { - /* For BLKPREP_KILL/DEFER the cmd was released */ - case BLKPREP_KILL: - goto kill; - case BLKPREP_DEFER: - goto defer; - } - + out: + switch (ret) { + case BLKPREP_KILL: + req->errors = DID_NO_CONNECT << 16; + break; + case BLKPREP_DEFER: /* - * Initialize the actual SCSI command for this request. + * 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 (req->flags & REQ_BLOCK_PC) { - scsi_setup_blk_pc_cmnd(cmd); - } else if (req->rq_disk) { - struct scsi_driver *drv; - - drv = *(struct scsi_driver **)req->rq_disk->private_data; - if (unlikely(!drv->init_command(cmd))) { - scsi_release_buffers(cmd); - scsi_put_command(cmd); - goto kill; - } - } + if (sdev->device_busy == 0) + blk_plug_device(q); + break; + default: + req->cmd_flags |= REQ_DONTPREP; } - /* - * The request is now prepped, no need to come back here - */ - req->flags |= REQ_DONTPREP; - 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; - kill: - req->errors = DID_NO_CONNECT << 16; - return BLKPREP_KILL; + return ret; } /* @@ -1622,8 +1476,9 @@ static void scsi_request_fn(struct request_queue *q) if (unlikely(cmd == NULL)) { printk(KERN_CRIT "impossible request in %s.\n" "please mail a stack trace to " - "linux-scsi@vger.kernel.org", + "linux-scsi@vger.kernel.org\n", __FUNCTION__); + blk_dump_rq_flags(req, "foo"); BUG(); } spin_lock(shost->host_lock); @@ -1714,29 +1569,40 @@ u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) } 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, NULL); + 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); - blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); - blk_queue_softirq_done(q, scsi_softirq_done); 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) { @@ -2124,6 +1990,7 @@ 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; @@ -2134,6 +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: @@ -2363,3 +2233,61 @@ scsi_target_unblock(struct device *dev) 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);