Messages in this thread Patch in this message | | | Date | Fri, 28 Feb 2014 18:27:18 +0800 | From | Gu Zheng <> | Subject | [PATCH 2/2] aio: make aio_read_events_ring be aware of aio_complete |
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Commit 5ffac122dbda8(aio: Don't use ctx->tail unnecessarily) uses ring->tail rather than the ctx->tail, but with this change, we fetch 'tail' only once at the start, so that we can not be aware of adding event by aio_complete when reading events. It seems a regression. So here we fetch the ring->tail in start of the loop each time to make it be aware of adding event from aio_complete.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> --- fs/aio.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c index 7eaa631..f5b8551 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1029,10 +1029,14 @@ static long aio_read_events_ring(struct kioctx *ctx, struct io_event *ev; struct page *page; - avail = (head <= tail ? tail : ctx->nr_events) - head; + ring = kmap_atomic(ctx->ring_pages[0]); + tail = ring->tail; + kunmap_atomic(ring); + if (head == tail) break; + avail = (head <= tail ? tail : ctx->nr_events) - head; avail = min(avail, nr - ret); avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE)); -- 1.7.7
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