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io_uring: make timeout sequence == 0 mean no sequence 

Currently we make sequence == 0 be the same as sequence == 1, but that's
not super useful if the intent is really to have a timeout that's just
a pure timeout.

If the user passes in sqe->off == 0, then don't apply any sequence logic
to the request, let it purely be driven by the timeout specified.

Reported-by: 李通洲 <carter.li@eoitek.com>
Reviewed-by: 李通洲 <carter.li@eoitek.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2019-11-11 23:34:31 -07:00
parent 65de03e251
commit 93bd25bb69
1 changed files with 22 additions and 7 deletions
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25
fs/io_uring.c
View File

@ -326,6 +326,7 @@ struct io_kiocb {
#define REQ_F_TIMEOUT 1024 /* timeout request */
#define REQ_F_ISREG 2048 /* regular file */
#define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */
#define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */
u64 user_data;
u32 result;
u32 sequence;
@ -453,10 +454,14 @@ static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx)
struct io_kiocb *req;
req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list);
if (req && !__io_sequence_defer(ctx, req)) {
if (req) {
if (req->flags & REQ_F_TIMEOUT_NOSEQ)
return NULL;
if (!__io_sequence_defer(ctx, req)) {
list_del_init(&req->list);
return req;
}
}
return NULL;
}
@ -1941,18 +1946,24 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (get_timespec64(&ts, u64_to_user_ptr(sqe->addr)))
return -EFAULT;
req->flags |= REQ_F_TIMEOUT;
/*
* sqe->off holds how many events that need to occur for this
* timeout event to be satisfied.
* timeout event to be satisfied. If it isn't set, then this is
* a pure timeout request, sequence isn't used.
*/
count = READ_ONCE(sqe->off);
if (!count)
count = 1;
if (!count) {
req->flags |= REQ_F_TIMEOUT_NOSEQ;
spin_lock_irq(&ctx->completion_lock);
entry = ctx->timeout_list.prev;
goto add;
}
req->sequence = ctx->cached_sq_head + count - 1;
/* reuse it to store the count */
req->submit.sequence = count;
req->flags |= REQ_F_TIMEOUT;
/*
* Insertion sort, ensuring the first entry in the list is always
@ -1964,6 +1975,9 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
unsigned nxt_sq_head;
long long tmp, tmp_nxt;
if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)
continue;
/*
* Since cached_sq_head + count - 1 can overflow, use type long
* long to store it.
@ -1990,6 +2004,7 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
nxt->sequence++;
}
req->sequence -= span;
add:
list_add(&req->list, entry);
spin_unlock_irq(&ctx->completion_lock);