| Message ID | 0aef40399ba75b1a4d2c2e85e6e8fd93c02fc6e4.1655814213.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [5.19] io_uring: fix req->apoll_events | expand |
On 6/21/22 13:25, Pavel Begunkov wrote: > apoll_events should be set once in the beginning of poll arming just as > poll->events and not change after. However, currently io_uring resets it > on each __io_poll_execute() for no clear reason. There is also a place > in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a > multishot, but forget to do the same thing with ->apoll_events, which is > buggy. > > Fixes: 81459350d581e ("io_uring: cache req->apoll->events in req->cflags") > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > fs/io_uring.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 87c65a358678..ebda9a565fc0 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -6954,7 +6954,8 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) > io_req_complete_failed(req, ret); > } > > -static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) > +static void __io_poll_execute(struct io_kiocb *req, int mask, > + __poll_t __maybe_unused events) Killing @events would add extra rebase conflicts, so left it here and will send a clean up for 5.20. > { > req->cqe.res = mask; > /* > @@ -6963,7 +6964,6 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) > * CPU. We want to avoid pulling in req->apoll->events for that > * case. > */ > - req->apoll_events = events; > if (req->opcode == IORING_OP_POLL_ADD) > req->io_task_work.func = io_poll_task_func; > else > @@ -7114,6 +7114,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, > io_init_poll_iocb(poll, mask, io_poll_wake); > poll->file = req->file; > > + req->apoll_events = poll->events; > + > ipt->pt._key = mask; > ipt->req = req; > ipt->error = 0; > @@ -7144,8 +7146,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, > > if (mask) { > /* can't multishot if failed, just queue the event we've got */ > - if (unlikely(ipt->error || !ipt->nr_entries)) > + if (unlikely(ipt->error || !ipt->nr_entries)) { > poll->events |= EPOLLONESHOT; > + req->apoll_events |= EPOLLONESHOT; > + } > __io_poll_execute(req, mask, poll->events); > return 0; > } > @@ -7392,7 +7396,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe > return -EINVAL; > > io_req_set_refcount(req); > - req->apoll_events = poll->events = io_poll_parse_events(sqe, flags); > + poll->events = io_poll_parse_events(sqe, flags); > return 0; > } >
On 6/21/22 20:25, Pavel Begunkov wrote: > apoll_events should be set once in the beginning of poll arming just as > poll->events and not change after. However, currently io_uring resets it > on each __io_poll_execute() for no clear reason. There is also a place > in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a > multishot, but forget to do the same thing with ->apoll_events, which is > buggy. > > Fixes: 81459350d581e ("io_uring: cache req->apoll->events in req->cflags") > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > fs/io_uring.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 87c65a358678..ebda9a565fc0 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -6954,7 +6954,8 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) > io_req_complete_failed(req, ret); > } > > -static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) > +static void __io_poll_execute(struct io_kiocb *req, int mask, > + __poll_t __maybe_unused events) > { > req->cqe.res = mask; > /* > @@ -6963,7 +6964,6 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) > * CPU. We want to avoid pulling in req->apoll->events for that > * case. > */ > - req->apoll_events = events; > if (req->opcode == IORING_OP_POLL_ADD) > req->io_task_work.func = io_poll_task_func; > else > @@ -7114,6 +7114,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, > io_init_poll_iocb(poll, mask, io_poll_wake); > poll->file = req->file; > > + req->apoll_events = poll->events; > + > ipt->pt._key = mask; > ipt->req = req; > ipt->error = 0; > @@ -7144,8 +7146,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, > > if (mask) { > /* can't multishot if failed, just queue the event we've got */ > - if (unlikely(ipt->error || !ipt->nr_entries)) > + if (unlikely(ipt->error || !ipt->nr_entries)) { > poll->events |= EPOLLONESHOT; > + req->apoll_events |= EPOLLONESHOT; > + } > __io_poll_execute(req, mask, poll->events); > return 0; > } > @@ -7392,7 +7396,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe > return -EINVAL; > > io_req_set_refcount(req); > - req->apoll_events = poll->events = io_poll_parse_events(sqe, flags); > + poll->events = io_poll_parse_events(sqe, flags); > return 0; > } > Make sense, Reviewed-by: Hao Xu <howeyxu@tencent.com>
On Tue, 21 Jun 2022 13:25:06 +0100, Pavel Begunkov wrote: > apoll_events should be set once in the beginning of poll arming just as > poll->events and not change after. However, currently io_uring resets it > on each __io_poll_execute() for no clear reason. There is also a place > in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a > multishot, but forget to do the same thing with ->apoll_events, which is > buggy. > > [...] Applied, thanks! [1/1] io_uring: fix req->apoll_events commit: aacf2f9f382c91df73f33317e28a4c34c8038986 Best regards,
diff --git a/fs/io_uring.c b/fs/io_uring.c index 87c65a358678..ebda9a565fc0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6954,7 +6954,8 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) io_req_complete_failed(req, ret); } -static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) +static void __io_poll_execute(struct io_kiocb *req, int mask, + __poll_t __maybe_unused events) { req->cqe.res = mask; /* @@ -6963,7 +6964,6 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) * CPU. We want to avoid pulling in req->apoll->events for that * case. */ - req->apoll_events = events; if (req->opcode == IORING_OP_POLL_ADD) req->io_task_work.func = io_poll_task_func; else @@ -7114,6 +7114,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, io_init_poll_iocb(poll, mask, io_poll_wake); poll->file = req->file; + req->apoll_events = poll->events; + ipt->pt._key = mask; ipt->req = req; ipt->error = 0; @@ -7144,8 +7146,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, if (mask) { /* can't multishot if failed, just queue the event we've got */ - if (unlikely(ipt->error || !ipt->nr_entries)) + if (unlikely(ipt->error || !ipt->nr_entries)) { poll->events |= EPOLLONESHOT; + req->apoll_events |= EPOLLONESHOT; + } __io_poll_execute(req, mask, poll->events); return 0; } @@ -7392,7 +7396,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe return -EINVAL; io_req_set_refcount(req); - req->apoll_events = poll->events = io_poll_parse_events(sqe, flags); + poll->events = io_poll_parse_events(sqe, flags); return 0; }
apoll_events should be set once in the beginning of poll arming just as poll->events and not change after. However, currently io_uring resets it on each __io_poll_execute() for no clear reason. There is also a place in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a multishot, but forget to do the same thing with ->apoll_events, which is buggy. Fixes: 81459350d581e ("io_uring: cache req->apoll->events in req->cflags") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- fs/io_uring.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)