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authorAl Viro <viro@zeniv.linux.org.uk>2018-05-26 19:13:10 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-05-29 23:18:17 -0400
commitd2988bd412fac87859f0b68f5ea328fb0f09c216 (patch)
tree1a0df5ecf1d4c9400613e328e02d204ca01aa7a2
parent9061d14a8a97009085242b284b5b5f668af2bf97 (diff)
downloadlinux-d2988bd412fac87859f0b68f5ea328fb0f09c216.tar.bz2
aio_read_events_ring(): make a bit more readable
The logics for 'avail' is * not past the tail of cyclic buffer * no more than asked * not past the end of buffer * not past the end of a page Unobfuscate the last part. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/aio.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 6098b6ba8671..06761d5aac1e 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1197,14 +1197,13 @@ static long aio_read_events_ring(struct kioctx *ctx,
if (head == tail)
break;
- avail = min(avail, nr - ret);
- avail = min_t(long, avail, AIO_EVENTS_PER_PAGE -
- ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE));
-
pos = head + AIO_EVENTS_OFFSET;
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
pos %= AIO_EVENTS_PER_PAGE;
+ avail = min(avail, nr - ret);
+ avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
+
ev = kmap(page);
copy_ret = copy_to_user(event + ret, ev + pos,
sizeof(*ev) * avail);