[PATCH v1] eventfd: only return events requested in poll_mask()

From: Avi Kivity
Date: Fri Jun 08 2018 - 15:12:42 EST


The ->poll_mask() operation has a mask of events that the caller
is interested in, but we're returning all events regardless.

Change to return only the events the caller is interested in. This
fixes aio IO_CMD_POLL returning immediately when called with POLLIN
on an eventfd, since an eventfd is almost always ready for a write.

Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
fs/eventfd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index 61c9514da5e9..ceb1031f1cac 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -154,15 +154,15 @@ static __poll_t eventfd_poll_mask(struct file *file, __poll_t eventmask)
* eventfd_poll returns 0
*/
count = READ_ONCE(ctx->count);

if (count > 0)
- events |= EPOLLIN;
+ events |= (EPOLLIN & eventmask);
if (count == ULLONG_MAX)
events |= EPOLLERR;
if (ULLONG_MAX - 1 > count)
- events |= EPOLLOUT;
+ events |= (EPOLLOUT & eventmask);

return events;
}

static void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
--
2.14.4