[PATCH 10/32] aio: do fget() after aio_get_req()

From: Kent Overstreet
Date: Wed Dec 26 2012 - 21:05:07 EST


aio_get_req() will fail if we have the maximum number of requests
outstanding, which depending on the application may not be uncommon. So
avoid doing an unnecessary fget().

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
---
fs/aio.c | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 868ac0a..db6cb02 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -584,6 +584,8 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
{
assert_spin_locked(&ctx->ctx_lock);

+ if (req->ki_filp)
+ fput(req->ki_filp);
if (req->ki_eventfd != NULL)
eventfd_ctx_put(req->ki_eventfd);
if (req->ki_dtor)
@@ -602,9 +604,6 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
*/
static void __aio_put_req(struct kioctx *ctx, struct kiocb *req)
{
- pr_debug("(%p): f_count=%ld\n",
- req, atomic_long_read(&req->ki_filp->f_count));
-
assert_spin_locked(&ctx->ctx_lock);

req->ki_users--;
@@ -615,8 +614,6 @@ static void __aio_put_req(struct kioctx *ctx, struct kiocb *req)
req->ki_cancel = NULL;
req->ki_retry = NULL;

- fput(req->ki_filp);
- req->ki_filp = NULL;
really_put_req(ctx, req);
}

@@ -1264,7 +1261,6 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
bool compat)
{
struct kiocb *req;
- struct file *file;
ssize_t ret;

/* enforce forwards compatibility on users */
@@ -1283,16 +1279,16 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
return -EINVAL;
}

- file = fget(iocb->aio_fildes);
- if (unlikely(!file))
- return -EBADF;
-
req = aio_get_req(ctx, batch); /* returns with 2 references to req */
- if (unlikely(!req)) {
- fput(file);
+ if (unlikely(!req))
return -EAGAIN;
+
+ req->ki_filp = fget(iocb->aio_fildes);
+ if (unlikely(!req->ki_filp)) {
+ ret = -EBADF;
+ goto out_put_req;
}
- req->ki_filp = file;
+
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
/*
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
--
1.7.12

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