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eventfd: revised interface and cleanups

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Change the eventfd interface to de-couple the eventfd memory context, from
the file pointer instance.

Without such change, there is no clean way to racely free handle the
POLLHUP event sent when the last instance of the file* goes away.  Also,
now the internal eventfd APIs are using the eventfd context instead of the
file*.

This patch is required by KVM's IRQfd code, which is still under
development.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Davide Libenzi
2009-06-30 11:41:11 -07:00
committed by Linus Torvalds
parent f7c2df9b55
commit 133890103b
6 changed files with 149 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
fs/aio.c
View File

@@ -485,6 +485,8 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
{
assert_spin_locked(&ctx->ctx_lock);
if (req->ki_eventfd != NULL)
eventfd_ctx_put(req->ki_eventfd);
if (req->ki_dtor)
req->ki_dtor(req);
if (req->ki_iovec != &req->ki_inline_vec)
@@ -509,8 +511,6 @@ static void aio_fput_routine(struct work_struct *data)
/* Complete the fput(s) */
if (req->ki_filp != NULL)
__fput(req->ki_filp);
if (req->ki_eventfd != NULL)
__fput(req->ki_eventfd);
/* Link the iocb into the context's free list */
spin_lock_irq(&ctx->ctx_lock);
@@ -528,8 +528,6 @@ static void aio_fput_routine(struct work_struct *data)
*/
static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
{
int schedule_putreq = 0;
dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
req, atomic_long_read(&req->ki_filp->f_count));
@@ -549,24 +547,16 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
* we would not be holding the last reference to the file*, so
* this function will be executed w/out any aio kthread wakeup.
*/
if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count)))
schedule_putreq++;
else
req->ki_filp = NULL;
if (req->ki_eventfd != NULL) {
if (unlikely(atomic_long_dec_and_test(&req->ki_eventfd->f_count)))
schedule_putreq++;
else
req->ki_eventfd = NULL;
}
if (unlikely(schedule_putreq)) {
if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) {
get_ioctx(ctx);
spin_lock(&fput_lock);
list_add(&req->ki_list, &fput_head);
spin_unlock(&fput_lock);
queue_work(aio_wq, &fput_work);
} else
} else {
req->ki_filp = NULL;
really_put_req(ctx, req);
}
return 1;
}
@@ -1622,7 +1612,7 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
* an eventfd() fd, and will be signaled for each completed
* event using the eventfd_signal() function.
*/
req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
if (IS_ERR(req->ki_eventfd)) {
ret = PTR_ERR(req->ki_eventfd);
req->ki_eventfd = NULL;