* 03-06-24 Cleanup PARANOIA usage & code. <ldl@aros.net>
* 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements)
* possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall
- * why not: would need verify_area and friends, would share yet another
+ * why not: would need access_ok and friends, would share yet another
* structure with userland
*/
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/ioctl.h>
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
#include <net/sock.h>
#include <linux/devfs_fs_kernel.h>
#include <asm/uaccess.h>
+#include <asm/system.h>
#include <asm/types.h>
#include <linux/nbd.h>
#define DBG_RX 0x0200
#define DBG_TX 0x0400
static unsigned int debugflags;
+static unsigned int nbds_max = 16;
#endif /* NDEBUG */
static struct nbd_device nbd_dev[MAX_NBD];
* a single lock.
* Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
*/
-static spinlock_t nbd_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(nbd_lock);
#ifndef NDEBUG
static const char *ioctl_cmd_to_ascii(int cmd)
{
int uptodate = (req->errors == 0) ? 1 : 0;
request_queue_t *q = req->q;
- struct nbd_device *lo = req->rq_disk->private_data;
unsigned long flags;
dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
req, uptodate? "done": "failed");
- spin_lock(&lo->queue_lock);
- while (req->ref_count > 1) { /* still in send */
- spin_unlock(&lo->queue_lock);
- printk(KERN_DEBUG "%s: request %p still in use (%d), waiting\n",
- lo->disk->disk_name, req, req->ref_count);
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(HZ); /* wait a second */
- spin_lock(&lo->queue_lock);
- }
- spin_unlock(&lo->queue_lock);
-
spin_lock_irqsave(q->queue_lock, flags);
if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
- end_that_request_last(req);
+ end_that_request_last(req, uptodate);
}
spin_unlock_irqrestore(q->queue_lock, flags);
}
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
- msg.msg_namelen = 0;
msg.msg_flags = msg_flags | MSG_NOSIGNAL;
if (send)
return result;
}
-void nbd_send_req(struct nbd_device *lo, struct request *req)
+static int nbd_send_req(struct nbd_device *lo, struct request *req)
{
int result, i, flags;
struct nbd_request request;
request.len = htonl(size);
memcpy(request.handle, &req, sizeof(req));
- down(&lo->tx_lock);
-
- if (!sock || !lo->sock) {
- printk(KERN_ERR "%s: Attempted send on closed socket\n",
- lo->disk->disk_name);
- goto error_out;
- }
-
dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
lo->disk->disk_name, req,
nbdcmd_to_ascii(nbd_cmd(req)),
}
}
}
- up(&lo->tx_lock);
- return;
+ return 0;
error_out:
- up(&lo->tx_lock);
- req->errors++;
+ return 1;
}
static struct request *nbd_find_request(struct nbd_device *lo, char *handle)
struct request *req;
struct list_head *tmp;
struct request *xreq;
+ int err;
memcpy(&xreq, handle, sizeof(xreq));
+ err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq);
+ if (unlikely(err))
+ goto out;
+
spin_lock(&lo->queue_lock);
list_for_each(tmp, &lo->queue_head) {
req = list_entry(tmp, struct request, queuelist);
return req;
}
spin_unlock(&lo->queue_lock);
- return NULL;
+
+ err = -ENOENT;
+
+out:
+ return ERR_PTR(err);
}
static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
}
/* NULL returned = something went wrong, inform userspace */
-struct request *nbd_read_stat(struct nbd_device *lo)
+static struct request *nbd_read_stat(struct nbd_device *lo)
{
int result;
struct nbd_reply reply;
goto harderror;
}
req = nbd_find_request(lo, reply.handle);
- if (req == NULL) {
+ if (unlikely(IS_ERR(req))) {
+ result = PTR_ERR(req);
+ if (result != -ENOENT)
+ goto harderror;
+
printk(KERN_ERR "%s: Unexpected reply (%p)\n",
lo->disk->disk_name, reply.handle);
result = -EBADR;
return NULL;
}
-void nbd_do_it(struct nbd_device *lo)
+static void nbd_do_it(struct nbd_device *lo)
{
struct request *req;
return;
}
-void nbd_clear_que(struct nbd_device *lo)
+static void nbd_clear_que(struct nbd_device *lo)
{
struct request *req;
BUG_ON(lo->magic != LO_MAGIC);
- do {
- req = NULL;
- spin_lock(&lo->queue_lock);
- if (!list_empty(&lo->queue_head)) {
- req = list_entry(lo->queue_head.next, struct request, queuelist);
- list_del_init(&req->queuelist);
- }
- spin_unlock(&lo->queue_lock);
- if (req) {
- req->errors++;
- nbd_end_request(req);
- }
- } while (req);
+ /*
+ * Because we have set lo->sock to NULL under the tx_lock, all
+ * modifications to the list must have completed by now. For
+ * the same reason, the active_req must be NULL.
+ *
+ * As a consequence, we don't need to take the spin lock while
+ * purging the list here.
+ */
+ BUG_ON(lo->sock);
+ BUG_ON(lo->active_req);
+
+ while (!list_empty(&lo->queue_head)) {
+ req = list_entry(lo->queue_head.next, struct request,
+ queuelist);
+ list_del_init(&req->queuelist);
+ req->errors++;
+ nbd_end_request(req);
+ }
}
/*
BUG_ON(lo->magic != LO_MAGIC);
- if (!lo->file) {
- printk(KERN_ERR "%s: Request when not-ready\n",
- lo->disk->disk_name);
- goto error_out;
- }
nbd_cmd(req) = NBD_CMD_READ;
if (rq_data_dir(req) == WRITE) {
nbd_cmd(req) = NBD_CMD_WRITE;
req->errors = 0;
spin_unlock_irq(q->queue_lock);
- spin_lock(&lo->queue_lock);
-
- if (!lo->file) {
- spin_unlock(&lo->queue_lock);
- printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n",
- lo->disk->disk_name);
+ mutex_lock(&lo->tx_lock);
+ if (unlikely(!lo->sock)) {
+ mutex_unlock(&lo->tx_lock);
+ printk(KERN_ERR "%s: Attempted send on closed socket\n",
+ lo->disk->disk_name);
req->errors++;
nbd_end_request(req);
spin_lock_irq(q->queue_lock);
continue;
}
- list_add(&req->queuelist, &lo->queue_head);
- req->ref_count++; /* make sure req does not get freed */
- spin_unlock(&lo->queue_lock);
-
- nbd_send_req(lo, req);
+ lo->active_req = req;
- if (req->errors) {
+ if (nbd_send_req(lo, req) != 0) {
printk(KERN_ERR "%s: Request send failed\n",
lo->disk->disk_name);
+ req->errors++;
+ nbd_end_request(req);
+ } else {
spin_lock(&lo->queue_lock);
- list_del_init(&req->queuelist);
- req->ref_count--;
+ list_add(&req->queuelist, &lo->queue_head);
spin_unlock(&lo->queue_lock);
- nbd_end_request(req);
- spin_lock_irq(q->queue_lock);
- continue;
}
- spin_lock(&lo->queue_lock);
- req->ref_count--;
- spin_unlock(&lo->queue_lock);
+ lo->active_req = NULL;
+ mutex_unlock(&lo->tx_lock);
+ wake_up_all(&lo->active_wq);
+
spin_lock_irq(q->queue_lock);
continue;
case NBD_CLEAR_SOCK:
error = 0;
- down(&lo->tx_lock);
+ mutex_lock(&lo->tx_lock);
lo->sock = NULL;
- up(&lo->tx_lock);
- spin_lock(&lo->queue_lock);
+ mutex_unlock(&lo->tx_lock);
file = lo->file;
lo->file = NULL;
- spin_unlock(&lo->queue_lock);
nbd_clear_que(lo);
- spin_lock(&lo->queue_lock);
- if (!list_empty(&lo->queue_head)) {
- printk(KERN_ERR "nbd: disconnect: some requests are in progress -> please try again.\n");
- error = -EBUSY;
- }
- spin_unlock(&lo->queue_lock);
+ BUG_ON(!list_empty(&lo->queue_head));
if (file)
fput(file);
return error;
file = fget(arg);
if (file) {
inode = file->f_dentry->d_inode;
- if (inode->i_sock) {
+ if (S_ISSOCK(inode->i_mode)) {
lo->file = file;
lo->sock = SOCKET_I(inode);
error = 0;
* FIXME: This code is duplicated from sys_shutdown, but
* there should be a more generic interface rather than
* calling socket ops directly here */
- down(&lo->tx_lock);
+ mutex_lock(&lo->tx_lock);
if (lo->sock) {
printk(KERN_WARNING "%s: shutting down socket\n",
lo->disk->disk_name);
SEND_SHUTDOWN|RCV_SHUTDOWN);
lo->sock = NULL;
}
- up(&lo->tx_lock);
- spin_lock(&lo->queue_lock);
+ mutex_unlock(&lo->tx_lock);
file = lo->file;
lo->file = NULL;
- spin_unlock(&lo->queue_lock);
nbd_clear_que(lo);
printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
if (file)
fput(file);
return lo->harderror;
case NBD_CLEAR_QUE:
- down(&lo->tx_lock);
- if (lo->sock) {
- up(&lo->tx_lock);
- return 0; /* probably should be error, but that would
- * break "nbd-client -d", so just return 0 */
- }
- up(&lo->tx_lock);
- nbd_clear_que(lo);
+ /*
+ * This is for compatibility only. The queue is always cleared
+ * by NBD_DO_IT or NBD_CLEAR_SOCK.
+ */
+ BUG_ON(!lo->sock && !list_empty(&lo->queue_head));
return 0;
case NBD_PRINT_DEBUG:
printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
int err = -ENOMEM;
int i;
- if (sizeof(struct nbd_request) != 28) {
- printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" );
- return -EIO;
+ BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
+
+ if (nbds_max > MAX_NBD) {
+ printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD,
+ nbds_max);
+ return -EINVAL;
}
- for (i = 0; i < MAX_NBD; i++) {
+ for (i = 0; i < nbds_max; i++) {
struct gendisk *disk = alloc_disk(1);
if (!disk)
goto out;
dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
devfs_mk_dir("nbd");
- for (i = 0; i < MAX_NBD; i++) {
+ for (i = 0; i < nbds_max; i++) {
struct gendisk *disk = nbd_dev[i].disk;
nbd_dev[i].file = NULL;
nbd_dev[i].magic = LO_MAGIC;
nbd_dev[i].flags = 0;
spin_lock_init(&nbd_dev[i].queue_lock);
INIT_LIST_HEAD(&nbd_dev[i].queue_head);
- init_MUTEX(&nbd_dev[i].tx_lock);
+ mutex_init(&nbd_dev[i].tx_lock);
+ init_waitqueue_head(&nbd_dev[i].active_wq);
nbd_dev[i].blksize = 1024;
nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
disk->major = NBD_MAJOR;
static void __exit nbd_cleanup(void)
{
int i;
- for (i = 0; i < MAX_NBD; i++) {
+ for (i = 0; i < nbds_max; i++) {
struct gendisk *disk = nbd_dev[i].disk;
+ nbd_dev[i].magic = 0;
if (disk) {
del_gendisk(disk);
blk_cleanup_queue(disk->queue);
MODULE_DESCRIPTION("Network Block Device");
MODULE_LICENSE("GPL");
+module_param(nbds_max, int, 0444);
+MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize.");
#ifndef NDEBUG
-MODULE_PARM(debugflags, "i");
+module_param(debugflags, int, 0644);
MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
#endif
git://git.onelab.eu / linux-2.6.git / blobdiff