This patch ensures that aio ops won't be retried. Code that uses EIOCBRETRY
will fail to build and modules that reference kick_iocb() won't load.
This simplifies an upcoming patch by ensuring that it doesn't have to support
aio ops that retry. Further patches could remove much more of fs/aio.c if we
chose to remove retry-based aio support.
Signed-off-by: Zach Brown <zach.brown@xxxxxxxxxx>
---
fs/aio.c | 82 +-----------------------------------------------
fs/ocfs2/dlmglue.c | 2 +-
fs/read_write.c | 34 ++------------------
include/linux/aio.h | 11 ------
include/linux/errno.h | 1 -
5 files changed, 6 insertions(+), 124 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 02a2c93..2406981 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -697,37 +697,12 @@ static ssize_t aio_run_iocb(struct kiocb *iocb)
*/
ret = retry(iocb);
- if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
+ if (ret != -EIOCBQUEUED) {
BUG_ON(!list_empty(&iocb->ki_wait.task_list));
aio_complete(iocb, ret, 0);
}
out:
spin_lock_irq(&ctx->ctx_lock);
-
- if (-EIOCBRETRY == ret) {
- /*
- * OK, now that we are done with this iteration
- * and know that there is more left to go,
- * this is where we let go so that a subsequent
- * "kick" can start the next iteration
- */
-
- /* will make __queue_kicked_iocb succeed from here on */
- INIT_LIST_HEAD(&iocb->ki_run_list);
- /* we must queue the next iteration ourselves, if it
- * has already been kicked */
- if (kiocbIsKicked(iocb)) {
- __queue_kicked_iocb(iocb);
-
- /*
- * __queue_kicked_iocb will always return 1 here, because
- * iocb->ki_run_list is empty at this point so it should
- * be safe to unconditionally queue the context into the
- * work queue.
- */
- aio_queue_work(ctx);
- }
- }
return ret;
}
@@ -840,56 +815,6 @@ static void aio_kick_handler(struct work_struct *work)
queue_delayed_work(aio_wq, &ctx->wq, 0);
}
-
-/*
- * Called by kick_iocb to queue the kiocb for retry
- * and if required activate the aio work queue to process
- * it
- */
-static void try_queue_kicked_iocb(struct kiocb *iocb)
-{
- struct kioctx *ctx = iocb->ki_ctx;
- 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 */
- if (!kiocbTryKick(iocb))
- run = __queue_kicked_iocb(iocb);
- spin_unlock_irqrestore(&ctx->ctx_lock, flags);
- if (run)
- aio_queue_work(ctx);
-}
-
-/*
- * kick_iocb:
- * Called typically from a wait queue callback context
- * (aio_wake_function) to trigger a retry of the iocb.
- * The retry is usually executed by aio workqueue
- * threads (See aio_kick_handler).
- */
-void kick_iocb(struct kiocb *iocb)
-{
- /* sync iocbs are easy: they can only ever be executing from a
- * single context. */
- if (is_sync_kiocb(iocb)) {
- kiocbSetKicked(iocb);
- wake_up_process(iocb->ki_obj.tsk);
- return;
- }
-
- try_queue_kicked_iocb(iocb);
-}
-EXPORT_SYMBOL(kick_iocb);
-
/* aio_complete
* Called when the io request on the given iocb is complete.
* Returns true if this is the last user of the request. The
@@ -1352,7 +1277,7 @@ static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
/* If we managed to write some out we return that, rather than
* the eventual error. */
if (opcode == IOCB_CMD_PWRITEV
- && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
+ && ret < 0 && ret != -EIOCBQUEUED
&& iocb->ki_nbytes - iocb->ki_left)
ret = iocb->ki_nbytes - iocb->ki_left;
@@ -1524,10 +1449,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
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;
}
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 0d38d67..fb7bb85 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2282,7 +2282,7 @@ int ocfs2_inode_lock_full_nested(struct inode *inode,
status = __ocfs2_cluster_lock(osb, lockres, level, dlm_flags,
arg_flags, subclass, _RET_IP_);
if (status < 0) {
- if (status != -EAGAIN && status != -EIOCBRETRY)
+ if (status != -EAGAIN)
mlog_errno(status);
goto bail;
}
diff --git a/fs/read_write.c b/fs/read_write.c
index 3ac2898..a6d1b45 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -239,16 +239,6 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
}
-static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
-{
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!kiocbIsKicked(iocb))
- schedule();
- else
- kiocbClearKicked(iocb);
- __set_current_state(TASK_RUNNING);
-}
-
ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
struct iovec iov = { .iov_base = buf, .iov_len = len };
@@ -259,13 +249,7 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp
kiocb.ki_pos = *ppos;
kiocb.ki_left = len;
- for (;;) {
- ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
- if (ret != -EIOCBRETRY)
- break;
- wait_on_retry_sync_kiocb(&kiocb);
- }
-
+ ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
@@ -314,13 +298,7 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
kiocb.ki_pos = *ppos;
kiocb.ki_left = len;
- for (;;) {
- ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
- if (ret != -EIOCBRETRY)
- break;
- wait_on_retry_sync_kiocb(&kiocb);
- }
-
+ ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
@@ -494,13 +472,7 @@ ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
kiocb.ki_left = len;
kiocb.ki_nbytes = len;
- for (;;) {
- ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
- if (ret != -EIOCBRETRY)
- break;
- wait_on_retry_sync_kiocb(&kiocb);
- }
-
+ ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
if (ret == -EIOCBQUEUED)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
diff --git a/include/linux/aio.h b/include/linux/aio.h
index aea219d..4f88ec2 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -74,15 +74,6 @@ struct kioctx;
* not ask the method again -- ki_retry must ensure forward progress.
* aio_complete() must be called once and only once in the future, multiple
* calls may result in undefined behaviour.
- *
- * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
- * will be called on the kiocb pointer in the future. This may happen
- * through generic helpers that associate kiocb->ki_wait with a wait
- * queue head that ki_retry uses via current->io_wait. It can also happen
- * with custom tracking and manual calls to kick_iocb(), though that is
- * discouraged. In either case, kick_iocb() must be called once and only
- * once. ki_retry must ensure forward progress, the AIO core will wait
- * indefinitely for kick_iocb() to be called.
*/
struct kiocb {
struct list_head ki_run_list;
@@ -210,14 +201,12 @@ extern unsigned aio_max_size;
#ifdef CONFIG_AIO
extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
extern int aio_put_req(struct kiocb *iocb);
-extern void kick_iocb(struct kiocb *iocb);
extern int aio_complete(struct kiocb *iocb, long res, long res2);
struct mm_struct;
extern void exit_aio(struct mm_struct *mm);
#else
static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
static inline int aio_put_req(struct kiocb *iocb) { return 0; }
-static inline void kick_iocb(struct kiocb *iocb) { }
static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; }
struct mm_struct;
static inline void exit_aio(struct mm_struct *mm) { }
diff --git a/include/linux/errno.h b/include/linux/errno.h
index 4668583..63a1f15 100644
--- a/include/linux/errno.h
+++ b/include/linux/errno.h
@@ -27,7 +27,6 @@
#define EBADTYPE 527 /* Type not supported by server */
#define EJUKEBOX 528 /* Request initiated, but will not complete before timeout */
#define EIOCBQUEUED 529 /* iocb queued, will get completion event */
-#define EIOCBRETRY 530 /* iocb queued, will trigger a retry */
#endif
--
1.6.2.5
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
