linux-kernel - [PATCH AUTOSEL 5.0 65/66] aio: store event at final iocb

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Date:   Wed, 24 Apr 2019 10:33:39 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Al Viro <viro@...iv.linux.org.uk>, Sasha Levin <sashal@...nel.org>,
        linux-aio@...ck.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH AUTOSEL 5.0 65/66] aio: store event at final iocb_put()

From: Al Viro <viro@...iv.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@...iv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@...nel.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