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io_uring: fix stopping iopoll'ing too early

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Nobody adjusts *nr_events (number of completed requests) before calling
io_iopoll_getevents(), so the passed @min shouldn't be adjusted as well.
Othewise it can return less than initially asked @min without hitting
need_resched().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-07-06 17:59:30 +03:00 committed by Jens Axboe
parent 3aadc23e60
commit eba0a4dd2a
1 changed files with 2 additions and 7 deletions
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9
fs/io_uring.c
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@ -2044,7 +2044,7 @@ static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
ret = io_do_iopoll(ctx, nr_events, min);
if (ret < 0)
return ret;
if (!min || *nr_events >= min)
if (*nr_events >= min)
return 0;
}
@ -2087,8 +2087,6 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
*/
mutex_lock(&ctx->uring_lock);
do {
int tmin = 0;
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
@ -2113,10 +2111,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
mutex_lock(&ctx->uring_lock);
}
if (*nr_events < min)
tmin = min - *nr_events;
ret = io_iopoll_getevents(ctx, nr_events, tmin);
ret = io_iopoll_getevents(ctx, nr_events, min);
if (ret <= 0)
break;
ret = 0;