io_uring: fix infinite wait in khread_park() on io_finish_async()

[linux-2.6-block.git] / fs / io_uring.c

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ac04076938348defd55ab3726addeba00d30861a..67d1aae349d7dd6fc2ef4a1ee3b193378bf7d754 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -231,7 +231,6 @@ struct io_ring_ctx {
        struct task_struct      *sqo_thread;    /* if using sq thread polling */
        struct mm_struct        *sqo_mm;
        wait_queue_head_t       sqo_wait;
-       unsigned                sqo_stop;
 
        struct {
                /* CQ ring */
@@ -2015,7 +2014,7 @@ static int io_sq_thread(void *data)
        set_fs(USER_DS);
 
        timeout = inflight = 0;
-       while (!kthread_should_stop() && !ctx->sqo_stop) {
+       while (!kthread_should_park()) {
                bool all_fixed, mm_fault = false;
                int i;
 
@@ -2077,7 +2076,7 @@ static int io_sq_thread(void *data)
                        smp_mb();
 
                        if (!io_get_sqring(ctx, &sqes[0])) {
-                               if (kthread_should_stop()) {
+                               if (kthread_should_park()) {
                                        finish_wait(&ctx->sqo_wait, &wait);
                                        break;
                                }
@@ -2127,8 +2126,7 @@ static int io_sq_thread(void *data)
                mmput(cur_mm);
        }
 
-       if (kthread_should_park())
-               kthread_parkme();
+       kthread_parkme();
 
        return 0;
 }
@@ -2260,8 +2258,11 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 static void io_sq_thread_stop(struct io_ring_ctx *ctx)
 {
        if (ctx->sqo_thread) {
-               ctx->sqo_stop = 1;
-               mb();
+               /*
+                * The park is a bit of a work-around, without it we get
+                * warning spews on shutdown with SQPOLL set and affinity
+                * set to a single CPU.
+                */
                kthread_park(ctx->sqo_thread);
                kthread_stop(ctx->sqo_thread);
                ctx->sqo_thread = NULL;