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io_uring: terminate multishot poll for CQ ring overflow

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If we hit overflow and fail to allocate an overflow entry for the
completion, terminate the multishot poll mode.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-02-23 09:02:26 -07:00
parent b2c3f7e171
commit 5082620fb2
1 changed files with 12 additions and 8 deletions
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20
fs/io_uring.c
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@ -1044,6 +1044,7 @@ static void io_rsrc_put_work(struct work_struct *work);
static void io_req_task_queue(struct io_kiocb *req);
static void io_submit_flush_completions(struct io_comp_state *cs,
struct io_ring_ctx *ctx);
static bool io_poll_remove_waitqs(struct io_kiocb *req);
static int io_req_prep_async(struct io_kiocb *req);
static struct kmem_cache *req_cachep;
@ -1501,7 +1502,7 @@ static inline void req_ref_get(struct io_kiocb *req)
atomic_inc(&req->refs);
}
static void __io_cqring_fill_event(struct io_kiocb *req, long res,
static bool __io_cqring_fill_event(struct io_kiocb *req, long res,
unsigned int cflags)
{
struct io_ring_ctx *ctx = req->ctx;
@ -1519,7 +1520,7 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res,
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
return;
return true;
}
if (!ctx->cq_overflow_flushed &&
!atomic_read(&req->task->io_uring->in_idle)) {
@ -1537,7 +1538,7 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res,
ocqe->cqe.res = res;
ocqe->cqe.flags = cflags;
list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
return;
return true;
}
overflow:
/*
@ -1546,6 +1547,7 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res,
* on the floor.
*/
WRITE_ONCE(ctx->rings->cq_overflow, ++ctx->cached_cq_overflow);
return false;
}
static void io_cqring_fill_event(struct io_kiocb *req, long res)
@ -4907,14 +4909,14 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
error = -ECANCELED;
req->poll.events |= EPOLLONESHOT;
}
if (error || (req->poll.events & EPOLLONESHOT)) {
io_poll_remove_double(req);
if (!error)
error = mangle_poll(mask);
if (!__io_cqring_fill_event(req, error, flags) ||
(req->poll.events & EPOLLONESHOT)) {
io_poll_remove_waitqs(req);
req->poll.done = true;
flags = 0;
}
if (!error)
error = mangle_poll(mask);
__io_cqring_fill_event(req, error, flags);
io_commit_cqring(ctx);
return !(flags & IORING_CQE_F_MORE);
}
@ -5205,6 +5207,8 @@ static bool __io_poll_remove_one(struct io_kiocb *req,
{
bool do_complete = false;
if (!poll->head)
return false;
spin_lock(&poll->head->lock);
WRITE_ONCE(poll->canceled, true);
if (!list_empty(&poll->wait.entry)) {