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| author |  Jens Axboe <axboe@kernel.dk>
| 2020-08-25 12:27:50 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk>
| 2020-08-25 12:27:50 -0600 |
| commit | 9dab14b81807a40dab8e464ec87043935c562c2c (patch) | |
| tree | ee5aaa05cb9cbcd504f81dcb77cbb46675f00d0d /fs | |
| parent | io_uring: fix imbalanced sqo_mm accounting (diff) | |
| download | linux-9dab14b81807a40dab8e464ec87043935c562c2c.tar.gz linux-9dab14b81807a40dab8e464ec87043935c562c2c.tar.bz2 linux-9dab14b81807a40dab8e464ec87043935c562c2c.zip | |
io_uring: don't use poll handler if file can't be nonblocking read/written
There's no point in using the poll handler if we can't do a nonblocking
IO attempt of the operation, since we'll need to go async anyway. In
fact this is actively harmful, as reading from eg pipes won't return 0
to indicate EOF.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Benedikt Ames <wisp3rwind@posteo.eu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 384df86dfc69..d15139088e4c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4889,12 +4889,20 @@ static bool io_arm_poll_handler(struct io_kiocb *req) struct async_poll *apoll; struct io_poll_table ipt; __poll_t mask, ret; + int rw; if (!req->file || !file_can_poll(req->file)) return false; if (req->flags & REQ_F_POLLED) return false; - if (!def->pollin && !def->pollout) + if (def->pollin) + rw = READ; + else if (def->pollout) + rw = WRITE; + else + return false; + /* if we can't nonblock try, then no point in arming a poll handler */ + if (!io_file_supports_async(req->file, rw)) return false; apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC); |