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From: Kent Overstreet <kent.overstreet@linux.dev>
To: linux-kernel@vger.kernel.org
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
	linux-aio@kvack.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 1/2] fs/aio: Use kmap_local() instead of kmap()
Date: Wed, 18 Jan 2023 10:26:02 -0500	[thread overview]
Message-ID: <20230118152603.28301-1-kent.overstreet@linux.dev> (raw)

Originally, we used kmap() instead of kmap_atomic() for reading events
out of the completion ringbuffer because we're using copy_to_user(),
which can fault.

Now that kmap_local() is a thing, use that instead.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Benjamin LaHaise <bcrl@kvack.org
Cc: linux-aio@kvack.org
Cc: linux-fsdevel@vger.kernel.org
---
 fs/aio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 5b2ff20ad3..3f795ed2a2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1246,10 +1246,10 @@ static long aio_read_events_ring(struct kioctx *ctx,
 		avail = min(avail, nr - ret);
 		avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
 
-		ev = kmap(page);
+		ev = kmap_local_page(page);
 		copy_ret = copy_to_user(event + ret, ev + pos,
 					sizeof(*ev) * avail);
-		kunmap(page);
+		kunmap_local(ev);
 
 		if (unlikely(copy_ret)) {
 			ret = -EFAULT;
-- 
2.39.0


             reply	other threads:[~2023-01-18 15:55 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-18 15:26 Kent Overstreet [this message]
2023-01-18 15:26 ` [PATCH 2/2] fs/aio: obey min_nr when doing wakeups Kent Overstreet
2023-01-18 18:19 ` [PATCH 1/2] fs/aio: Use kmap_local() instead of kmap() Jeff Moyer
2023-01-20 14:03 ` [PATCH v2] fs/aio: obey min_nr when doing wakeups Kent Overstreet
2023-01-20 19:47   ` Jeff Moyer
2023-01-23 16:17     ` Jeff Moyer
2023-01-23 19:54       ` Kent Overstreet

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