[PATCH AUTOSEL 5.0 65/66] aio: store event at final iocb_put()

Sasha Levin
2019-04-24T14:36:51Z

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit 2bb874c0d873d13bd9b9b9c6d7b7c4edab18c8b4 ]

Instead of having aio_complete() set ->ki_res.{res,res2}, do that
explicitly in its callers, drop the reference (as aio_complete()
used to do) and delay the rest until the final iocb_put().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/aio.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 387b224217b5..82bf5dffb272 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1077,16 +1077,10 @@ static inline void iocb_destroy(struct aio_kiocb *iocb)
kmem_cache_free(kiocb_cachep, iocb);
}

-static inline void iocb_put(struct aio_kiocb *iocb)
-{
- if (refcount_dec_and_test(&iocb->ki_refcnt))
- iocb_destroy(iocb);
-}
-
/* aio_complete
* Called when the io request on the given iocb is complete.
*/
-static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
+static void aio_complete(struct aio_kiocb *iocb)
{
struct kioctx *ctx = iocb->ki_ctx;
struct aio_ring *ring;
@@ -1094,8 +1088,6 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
unsigned tail, pos, head;
unsigned long flags;

- iocb->ki_res.res = res;
- iocb->ki_res.res2 = res2;
/*
* Add a completion event to the ring buffer. Must be done holding
* ctx->completion_lock to prevent other code from messing with the tail
@@ -1161,7 +1153,14 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)

if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
- iocb_put(iocb);
+}
+
+static inline void iocb_put(struct aio_kiocb *iocb)
+{
+ if (refcount_dec_and_test(&iocb->ki_refcnt)) {
+ aio_complete(iocb);
+ iocb_destroy(iocb);
+ }
}

/* aio_read_events_ring
@@ -1435,7 +1434,9 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
file_end_write(kiocb->ki_filp);
}

- aio_complete(iocb, res, res2);
+ iocb->ki_res.res = res;
+ iocb->ki_res.res2 = res2;
+ iocb_put(iocb);
}

static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
@@ -1583,11 +1584,10 @@ static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,

static void aio_fsync_work(struct work_struct *work)
{
- struct fsync_iocb *req = container_of(work, struct fsync_iocb, work);
- int ret;
+ struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);

- ret = vfs_fsync(req->file, req->datasync);
- aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
+ iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
+ iocb_put(iocb);
}

static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
@@ -1608,7 +1608,8 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,

static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
{
- aio_complete(iocb, mangle_poll(mask), 0);
+ iocb->ki_res.res = mangle_poll(mask);
+ iocb_put(iocb);
}

static void aio_poll_complete_work(struct work_struct *work)
--
2.19.1