Re: [PATCH 1/6] Add a wait queue argument to wait_bit action()

Suparna Bhattacharya
2005-06-20T16:11:48Z

On Mon, Jun 20, 2005 at 09:31:26PM +0530, Suparna Bhattacharya wrote:

> Here is a little bit of background on the motivation behind this set of
> patches to update AIO for filtered wakeups:
>
> (a) Since the introduction of filtered wakeups support and
> the wait_bit_queue infrastructure in mainline, it is no longer
> sufficient to just embed a wait queue entry in the kiocb
> for AIO operations involving filtered wakeups.
> (b) Given that filesystem reads/writes use filtered wakeups underlying
> wait_on_page_bit, fixing this becomes a pre-req for buffered
> filesystem AIO.
> (c) The wait_bit_queue infrastructure actually enables a cleaner
> implementation of filesystem AIO because it already provides
> for an action routine intended to allow both blocking and
> non-blocking or asynchronous behaviour.
>
>> Updated to apply to 2.6.12-rc6.

Add a wait queue parameter to the action routine called by
__wait_on_bit to allow it to determine whether to block or
not.

Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com>

fs/buffer.c | 2 +-
kernel/wait.c | 14 ++++++++------
mm/filemap.c | 2 +-
3 files changed, 10 insertions(+), 8 deletions(-)

diff -puN kernel/wait.c~modify-wait-bit-action-args kernel/wait.c
--- linux-2.6.9-rc1-mm4/kernel/wait.c~modify-wait-bit-action-args 2004-09-10 16:52:04.000000000 +0530
+++ linux-2.6.9-rc1-mm4-suparna/kernel/wait.c 2004-09-10 16:52:04.000000000 +0530
@@ -152,14 +152,14 @@ EXPORT_SYMBOL(wake_bit_function);
*/
int __sched fastcall
__wait_on_bit(wait_queue_head_t *wq, struct wait_bit_queue *q,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *), unsigned mode)
{
int ret = 0;

do {
prepare_to_wait(wq, &q->wait, mode);
if (test_bit(q->key.bit_nr, q->key.flags))
- ret = (*action)(q->key.flags);
+ ret = (*action)(q->key.flags, &q->wait);
} while (test_bit(q->key.bit_nr, q->key.flags) && !ret);
finish_wait(wq, &q->wait);
return ret;
@@ -167,7 +167,8 @@ EXPORT_SYMBOL(__wait_on_bit);
EXPORT_SYMBOL(__wait_on_bit);

int __sched fastcall out_of_line_wait_on_bit(void *word, int bit,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *),
+ unsigned mode)
{
wait_queue_head_t *wq = bit_waitqueue(word, bit);
DEFINE_WAIT_BIT(wait, word, bit);
@@ -178,14 +179,14 @@ EXPORT_SYMBOL(out_of_line_wait_on_bit);

int __sched fastcall
__wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *), unsigned mode)
{
int ret = 0;

do {
prepare_to_wait_exclusive(wq, &q->wait, mode);
if (test_bit(q->key.bit_nr, q->key.flags)) {
- if ((ret = (*action)(q->key.flags)))
+ if ((ret = (*action)(q->key.flags, &q->wait)))
break;
}
} while (test_and_set_bit(q->key.bit_nr, q->key.flags));
@@ -195,7 +196,8 @@ __wait_on_bit_lock(wait_queue_head_t *wq
EXPORT_SYMBOL(__wait_on_bit_lock);

int __sched fastcall out_of_line_wait_on_bit_lock(void *word, int bit,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *wait),
+ unsigned mode)
{
wait_queue_head_t *wq = bit_waitqueue(word, bit);
DEFINE_WAIT_BIT(wait, word, bit);
diff -puN mm/filemap.c~modify-wait-bit-action-args mm/filemap.c
--- linux-2.6.9-rc1-mm4/mm/filemap.c~modify-wait-bit-action-args 2004-09-10 16:52:04.000000000 +0530
+++ linux-2.6.9-rc1-mm4-suparna/mm/filemap.c 2004-09-10 16:52:04.000000000 +0530
@@ -133,7 +133,7 @@ void remove_from_page_cache(struct page
}
EXPORT_SYMBOL(remove_from_page_cache);

-static int sync_page(void *word)
+static int sync_page(void *word, wait_queue_t *wait)
{
struct address_space *mapping;
struct page *page;
diff -puN fs/buffer.c~modify-wait-bit-action-args fs/buffer.c
--- linux-2.6.9-rc1-mm4/fs/buffer.c~modify-wait-bit-action-args 2004-09-10 16:52:04.000000000 +0530
+++ linux-2.6.9-rc1-mm4-suparna/fs/buffer.c 2004-09-10 16:52:04.000000000 +0530
@@ -52,7 +52,7 @@ void wake_up_buffer(struct buffer_head *
bh->b_private = private;
}

-static int sync_buffer(void *word)
+static int sync_buffer(void *word, wait_queue_t *wait)
{
struct block_device *bd;
struct buffer_head *bh

_
diff -urp linux-2.6.9-rc3/include/linux/wait.h linux-2.6.9-rc3-mm2/include/linux/wait.h
--- linux-2.6.9-rc3/include/linux/wait.h 2004-10-07 13:19:09.000000000 +0530
+++ linux-2.6.9-rc3-mm2/include/linux/wait.h 2004-10-07 12:04:17.000000000 +0530
@@ -140,11 +151,15 @@ void FASTCALL(__wake_up(wait_queue_head_
extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
-int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
-int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
+int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *,
+ int (*)(void *, wait_queue_t *), unsigned));
+int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *,
+ int (*)(void *, wait_queue_t *), unsigned));
void FASTCALL(wake_up_bit(void *, int));
-int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
-int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
+int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *,
+ wait_queue_t *), unsigned));
+int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *,
+ wait_queue_t *), unsigned));
wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));

#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
@@ -364,7 +392,8 @@ int wake_bit_function(wait_queue_t *wait
* but has no intention of setting it.
*/
static inline int wait_on_bit(void *word, int bit,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *),
+ unsigned mode)
{
if (!test_bit(bit, word))
return 0;
@@ -388,7 +417,8 @@ static inline int wait_on_bit(void *word
* clear with the intention of setting it, and when done, clearing it.
*/
static inline int wait_on_bit_lock(void *word, int bit,
- int (*action)(void *), unsigned mode)
+ int (*action)(void *, wait_queue_t *),
+ unsigned mode)
{
if (!test_and_set_bit(bit, word))
return 0;
diff -urp linux-2.6.9-rc3/include/linux/writeback.h linux-2.6.9-rc3-mm2/include/linux/writeback.h
--- linux-2.6.9-rc3/include/linux/writeback.h 2004-10-07 13:19:09.000000000 +0530
+++ linux-2.6.9-rc3-mm2/include/linux/writeback.h 2004-10-07 12:05:30.000000000 +0530
@@ -68,7 +68,7 @@ struct writeback_control {
*/
void writeback_inodes(struct writeback_control *wbc);
void wake_up_inode(struct inode *inode);
-int inode_wait(void *);
+int inode_wait(void *, wait_queue_t *);
void sync_inodes_sb(struct super_block *, int wait);
void sync_inodes(int wait);

diff -urp linux-2.6.9-rc3/fs/inode.c linux-2.6.9-rc3-mm2/fs/inode.c
--- linux-2.6.9-rc3/fs/inode.c 2004-10-07 13:19:03.000000000 +0530
+++ linux-2.6.9-rc3-mm2/fs/inode.c 2004-10-07 12:06:07.000000000 +0530
@@ -1264,7 +1264,7 @@ void remove_dquot_ref(struct super_block

#endif

-int inode_wait(void *word)
+int inode_wait(void *word, wait_queue_t *wait)
{
schedule();
return 0;