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>

diff --git a/fs/aio.c b/fs/aio.c
index 6098b6b..06761d5 100644 (file)
--- 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);