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bsg: fix a blocking read bug

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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>
This commit is contained in:
FUJITA Tomonori 2007-05-08 15:32:03 +02:00 committed by Jens Axboe
parent 4cf0723ac8
commit e7d7217324
1 changed files with 23 additions and 61 deletions
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84
block/bsg.c
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@ -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 @@ static inline int bsg_io_schedule(struct bsg_device *bd, int state)
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;