Don't know the reason, but it appears ki_wait field of iocb never gets used.
Signed-off-by: Shaohua Li <[email protected]>
diff --git a/fs/aio.c b/fs/aio.c
index 02a2c93..5ec1e70 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -697,10 +697,8 @@ static ssize_t aio_run_iocb(struct kiocb *iocb)
*/
ret = retry(iocb);
- if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
- BUG_ON(!list_empty(&iocb->ki_wait.task_list));
+ if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED)
aio_complete(iocb, ret, 0);
- }
out:
spin_lock_irq(&ctx->ctx_lock);
@@ -852,13 +850,6 @@ static void try_queue_kicked_iocb(struct kiocb *iocb)
unsigned long flags;
int run = 0;
- /* We're supposed to be the only path putting the iocb back on the run
- * list. If we find that the iocb is *back* on a wait queue already
- * than retry has happened before we could queue the iocb. This also
- * means that the retry could have completed and freed our iocb, no
- * good. */
- BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
-
spin_lock_irqsave(&ctx->ctx_lock, flags);
/* set this inside the lock so that we can't race with aio_run_iocb()
* testing it and putting the iocb on the run list under the lock */
@@ -1506,31 +1497,6 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
return 0;
}
-/*
- * aio_wake_function:
- * wait queue callback function for aio notification,
- * Simply triggers a retry of the operation via kick_iocb.
- *
- * This callback is specified in the wait queue entry in
- * a kiocb.
- *
- * Note:
- * This routine is executed with the wait queue lock held.
- * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
- * the ioctx lock inside the wait queue lock. This is safe
- * because this callback isn't used for wait queues which
- * are nested inside ioctx lock (i.e. ctx->wait)
- */
-static int aio_wake_function(wait_queue_t *wait, unsigned mode,
- int sync, void *key)
-{
- struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
-
- list_del_init(&wait->task_list);
- kick_iocb(iocb);
- return 1;
-}
-
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
struct iocb *iocb)
{
@@ -1592,8 +1558,6 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
req->ki_opcode = iocb->aio_lio_opcode;
- init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
- INIT_LIST_HEAD(&req->ki_wait.task_list);
ret = aio_setup_iocb(req);
diff --git a/include/linux/aio.h b/include/linux/aio.h
index aea219d..811dbb3 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -102,7 +102,6 @@ struct kiocb {
} ki_obj;
__u64 ki_user_data; /* user's data for completion */
- wait_queue_t ki_wait;
loff_t ki_pos;
void *private;
@@ -140,7 +139,6 @@ struct kiocb {
(x)->ki_dtor = NULL; \
(x)->ki_obj.tsk = tsk; \
(x)->ki_user_data = 0; \
- init_wait((&(x)->ki_wait)); \
} while (0)
#define AIO_RING_MAGIC 0xa10a10a1
@@ -223,8 +221,6 @@ struct mm_struct;
static inline void exit_aio(struct mm_struct *mm) { }
#endif /* CONFIG_AIO */
-#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
-
static inline struct kiocb *list_kiocb(struct list_head *h)
{
return list_entry(h, struct kiocb, ki_list);
Shaohua Li <[email protected]> writes:
> Don't know the reason, but it appears ki_wait field of iocb never gets used.
This looks like it should be rolled into Zach's patch series to get rid
of the retry based aio scheme.
Cheers,
Jeff
> Signed-off-by: Shaohua Li <[email protected]>
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 02a2c93..5ec1e70 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -697,10 +697,8 @@ static ssize_t aio_run_iocb(struct kiocb *iocb)
> */
> ret = retry(iocb);
>
> - if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
> - BUG_ON(!list_empty(&iocb->ki_wait.task_list));
> + if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED)
> aio_complete(iocb, ret, 0);
> - }
> out:
> spin_lock_irq(&ctx->ctx_lock);
>
> @@ -852,13 +850,6 @@ static void try_queue_kicked_iocb(struct kiocb *iocb)
> unsigned long flags;
> int run = 0;
>
> - /* We're supposed to be the only path putting the iocb back on the run
> - * list. If we find that the iocb is *back* on a wait queue already
> - * than retry has happened before we could queue the iocb. This also
> - * means that the retry could have completed and freed our iocb, no
> - * good. */
> - BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
> -
> spin_lock_irqsave(&ctx->ctx_lock, flags);
> /* set this inside the lock so that we can't race with aio_run_iocb()
> * testing it and putting the iocb on the run list under the lock */
> @@ -1506,31 +1497,6 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
> return 0;
> }
>
> -/*
> - * aio_wake_function:
> - * wait queue callback function for aio notification,
> - * Simply triggers a retry of the operation via kick_iocb.
> - *
> - * This callback is specified in the wait queue entry in
> - * a kiocb.
> - *
> - * Note:
> - * This routine is executed with the wait queue lock held.
> - * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
> - * the ioctx lock inside the wait queue lock. This is safe
> - * because this callback isn't used for wait queues which
> - * are nested inside ioctx lock (i.e. ctx->wait)
> - */
> -static int aio_wake_function(wait_queue_t *wait, unsigned mode,
> - int sync, void *key)
> -{
> - struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
> -
> - list_del_init(&wait->task_list);
> - kick_iocb(iocb);
> - return 1;
> -}
> -
> static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
> struct iocb *iocb)
> {
> @@ -1592,8 +1558,6 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
> req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
> req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
> req->ki_opcode = iocb->aio_lio_opcode;
> - init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
> - INIT_LIST_HEAD(&req->ki_wait.task_list);
>
> ret = aio_setup_iocb(req);
>
> diff --git a/include/linux/aio.h b/include/linux/aio.h
> index aea219d..811dbb3 100644
> --- a/include/linux/aio.h
> +++ b/include/linux/aio.h
> @@ -102,7 +102,6 @@ struct kiocb {
> } ki_obj;
>
> __u64 ki_user_data; /* user's data for completion */
> - wait_queue_t ki_wait;
> loff_t ki_pos;
>
> void *private;
> @@ -140,7 +139,6 @@ struct kiocb {
> (x)->ki_dtor = NULL; \
> (x)->ki_obj.tsk = tsk; \
> (x)->ki_user_data = 0; \
> - init_wait((&(x)->ki_wait)); \
> } while (0)
>
> #define AIO_RING_MAGIC 0xa10a10a1
> @@ -223,8 +221,6 @@ struct mm_struct;
> static inline void exit_aio(struct mm_struct *mm) { }
> #endif /* CONFIG_AIO */
>
> -#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
> -
> static inline struct kiocb *list_kiocb(struct list_head *h)
> {
> return list_entry(h, struct kiocb, ki_list);
> --
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On Thu, 12 Nov 2009 15:52:47 +0800
Shaohua Li <[email protected]> wrote:
> Don't know the reason, but it appears ki_wait field of iocb never gets used.
If we do this then kick_iocb() has only one in-kernel caller, in
drivers/usb/gadget/inode.c. I wonder if the gadget code really needs
to be using kick_iocb()?
> If we do this then kick_iocb() has only one in-kernel caller, in
> drivers/usb/gadget/inode.c. I wonder if the gadget code really needs
> to be using kick_iocb()?
I don't think that it needs to, no. It's only using the aio retry
functionality to perform a copy of read data into user space.
I have a patch to switch it to using schedule_work() instead:
http://marc.info/?l=linux-fsdevel&m=125624446623075&w=2
I've been focusing on other things instead of pushing that to the usb
folks to be tested and merged, though. I've cc:ed them in case they
want to run with this.
- z