* [PATCH] io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL
@ 2021-09-02 14:50 Jens Axboe
0 siblings, 0 replies; only message in thread
From: Jens Axboe @ 2021-09-02 14:50 UTC (permalink / raw)
To: io-uring
SQPOLL has a different thread doing submissions, we need to check for
that and use the right task context when updating the worker values.
Just hold the sqd->lock across the operation, this ensures that the
thread cannot go away while we poke at ->io_uring.
Link: https://github.com/axboe/liburing/issues/420
Fixes: 2e480058ddc2 ("io-wq: provide a way to limit max number of workers")
Reported-by: Johannes Lundberg <[email protected]>
Tested-by: Johannes Lundberg <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4a5eb9e856f0..ef0c7ecc03a0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10323,26 +10323,46 @@ static int io_unregister_iowq_aff(struct io_ring_ctx *ctx)
static int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
void __user *arg)
{
- struct io_uring_task *tctx = current->io_uring;
+ struct io_sq_data *sqd = NULL;
+ struct io_uring_task *tctx;
__u32 new_count[2];
int i, ret;
- if (!tctx || !tctx->io_wq)
- return -EINVAL;
if (copy_from_user(new_count, arg, sizeof(new_count)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(new_count); i++)
if (new_count[i] > INT_MAX)
return -EINVAL;
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ sqd = ctx->sq_data;
+ if (sqd) {
+ mutex_lock(&sqd->lock);
+ tctx = sqd->thread->io_uring;
+ }
+ } else {
+ tctx = current->io_uring;
+ }
+
+ ret = -EINVAL;
+ if (!tctx || !tctx->io_wq)
+ goto err;
+
ret = io_wq_max_workers(tctx->io_wq, new_count);
if (ret)
- return ret;
+ goto err;
+
+ if (sqd)
+ mutex_unlock(&sqd->lock);
if (copy_to_user(arg, new_count, sizeof(new_count)))
return -EFAULT;
return 0;
+err:
+ if (sqd)
+ mutex_unlock(&sqd->lock);
+ return ret;
}
static bool io_register_op_must_quiesce(int op)
--
Jens Axboe
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