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author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2007-05-08 15:32:03 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2007-07-16 08:52:46 +0200 |
commit | e7d72173248c29c6f9ba14e40374266e1b954964 (patch) | |
tree | 5f4d14d210ca3d49d209942be0ce60e65a433ce7 /block/bsg.c | |
parent | 4cf0723ac89b5f2189da2ad07ef875de26b83c77 (diff) | |
download | lwn-e7d72173248c29c6f9ba14e40374266e1b954964.tar.gz lwn-e7d72173248c29c6f9ba14e40374266e1b954964.zip |
bsg: fix a blocking read bug
This patch fixes a bug that read() returns ENODATA even with a
blocking file descriptor when there are no commands pending.
This also includes some cleanups.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/bsg.c')
-rw-r--r-- | block/bsg.c | 84 |
1 files changed, 23 insertions, 61 deletions
diff --git a/block/bsg.c b/block/bsg.c index a333c9337093..2f78d7d34b9d 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -115,9 +115,9 @@ static void bsg_free_command(struct bsg_command *bc) wake_up(&bd->wq_free); } -static struct bsg_command *__bsg_alloc_command(struct bsg_device *bd) +static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) { - struct bsg_command *bc = NULL; + struct bsg_command *bc = ERR_PTR(-EINVAL); spin_lock_irq(&bd->lock); @@ -131,6 +131,7 @@ static struct bsg_command *__bsg_alloc_command(struct bsg_device *bd) if (unlikely(!bc)) { spin_lock_irq(&bd->lock); bd->queued_cmds--; + bc = ERR_PTR(-ENOMEM); goto out; } @@ -198,30 +199,6 @@ unlock: return ret; } -/* - * get a new free command, blocking if needed and specified - */ -static struct bsg_command *bsg_get_command(struct bsg_device *bd) -{ - struct bsg_command *bc; - int ret; - - do { - bc = __bsg_alloc_command(bd); - if (bc) - break; - - ret = bsg_io_schedule(bd, TASK_INTERRUPTIBLE); - if (ret) { - bc = ERR_PTR(ret); - break; - } - - } while (1); - - return bc; -} - static int blk_fill_sgv4_hdr_rq(request_queue_t *q, struct request *rq, struct sg_io_v4 *hdr, int has_write_perm) { @@ -397,7 +374,7 @@ static inline struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) /* * Get a finished command from the done list */ -static struct bsg_command *__bsg_get_done_cmd(struct bsg_device *bd, int state) +static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) { struct bsg_command *bc; int ret; @@ -407,9 +384,14 @@ static struct bsg_command *__bsg_get_done_cmd(struct bsg_device *bd, int state) if (bc) break; - ret = bsg_io_schedule(bd, state); + if (!test_bit(BSG_F_BLOCK, &bd->flags)) { + bc = ERR_PTR(-EAGAIN); + break; + } + + ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); if (ret) { - bc = ERR_PTR(ret); + bc = ERR_PTR(-ERESTARTSYS); break; } } while (1); @@ -419,18 +401,6 @@ static struct bsg_command *__bsg_get_done_cmd(struct bsg_device *bd, int state) return bc; } -static struct bsg_command * -bsg_get_done_cmd(struct bsg_device *bd, const struct iovec *iov) -{ - return __bsg_get_done_cmd(bd, TASK_INTERRUPTIBLE); -} - -static struct bsg_command * -bsg_get_done_cmd_nosignals(struct bsg_device *bd) -{ - return __bsg_get_done_cmd(bd, TASK_UNINTERRUPTIBLE); -} - static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, struct bio *bio) { @@ -496,19 +466,16 @@ static int bsg_complete_all_commands(struct bsg_device *bd) */ ret = 0; do { - bc = bsg_get_done_cmd_nosignals(bd); - - /* - * we _must_ complete before restarting, because - * bsg_release can't handle this failing. - */ - if (PTR_ERR(bc) == -ERESTARTSYS) - continue; - if (IS_ERR(bc)) { - ret = PTR_ERR(bc); + spin_lock_irq(&bd->lock); + if (!bd->queued_cmds) { + spin_unlock_irq(&bd->lock); break; } + bc = bsg_get_done_cmd(bd); + if (IS_ERR(bc)) + break; + tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio); if (!ret) ret = tret; @@ -519,11 +486,9 @@ static int bsg_complete_all_commands(struct bsg_device *bd) return ret; } -typedef struct bsg_command *(*bsg_command_callback)(struct bsg_device *bd, const struct iovec *iov); - static ssize_t -__bsg_read(char __user *buf, size_t count, bsg_command_callback get_bc, - struct bsg_device *bd, const struct iovec *iov, ssize_t *bytes_read) +__bsg_read(char __user *buf, size_t count, struct bsg_device *bd, + const struct iovec *iov, ssize_t *bytes_read) { struct bsg_command *bc; int nr_commands, ret; @@ -534,7 +499,7 @@ __bsg_read(char __user *buf, size_t count, bsg_command_callback get_bc, ret = 0; nr_commands = count / sizeof(struct sg_io_v4); while (nr_commands) { - bc = get_bc(bd, iov); + bc = bsg_get_done_cmd(bd); if (IS_ERR(bc)) { ret = PTR_ERR(bc); break; @@ -598,8 +563,7 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) bsg_set_block(bd, file); bytes_read = 0; - ret = __bsg_read(buf, count, bsg_get_done_cmd, - bd, NULL, &bytes_read); + ret = __bsg_read(buf, count, bd, NULL, &bytes_read); *ppos = bytes_read; if (!bytes_read || (bytes_read && err_block_err(ret))) @@ -625,9 +589,7 @@ static ssize_t __bsg_write(struct bsg_device *bd, const char __user *buf, while (nr_commands) { request_queue_t *q = bd->queue; - bc = bsg_get_command(bd); - if (!bc) - break; + bc = bsg_alloc_command(bd); if (IS_ERR(bc)) { ret = PTR_ERR(bc); bc = NULL; |