ping... On 02/28/2014 06:27 PM, Gu Zheng wrote:
> 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.f...@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)); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
