[PATCH 2/2] io_uring: consider cgroup setting when binding sqpoll cpu

[Hao Xu <haoxu@linux.alibaba.com>]

Since sqthread is userspace like thread now, it should respect cgroup
setting, thus we should consider current allowed cpuset when doing
cpu binding for sqthread.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
 fs/io_uring.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7cc458e0b636..414dfedf79a7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -79,6 +79,7 @@
 #include <linux/pagemap.h>
 #include <linux/io_uring.h>
 #include <linux/tracehook.h>
+#include <linux/cpuset.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/io_uring.h>
@@ -7102,6 +7103,14 @@ static bool io_sqd_handle_event(struct io_sq_data *sqd)
 	return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
 }
 
+static inline int io_sq_bind_cpu(int cpu)
+{
+	if (test_cpu_in_current_cpuset(cpu))
+		set_cpus_allowed_ptr(current, cpumask_of(cpu));
+
+	return 0;
+}
+
 static int io_sq_thread(void *data)
 {
 	struct io_sq_data *sqd = data;
@@ -7112,11 +7121,9 @@ static int io_sq_thread(void *data)
 
 	snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
 	set_task_comm(current, buf);
-
 	if (sqd->sq_cpu != -1)
-		set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
-	else
-		set_cpus_allowed_ptr(current, cpu_online_mask);
+		io_sq_bind_cpu(sqd->sq_cpu);
+
 	current->flags |= PF_NO_SETAFFINITY;
 
 	mutex_lock(&sqd->lock);
@@ -8310,8 +8317,10 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
 			int cpu = p->sq_thread_cpu;
 
 			ret = -EINVAL;
-			if (cpu >= nr_cpu_ids || !cpu_online(cpu))
+			if (cpu >= nr_cpu_ids || !cpu_online(cpu) ||
+			    !test_cpu_in_current_cpuset(cpu))
 				goto err_sqpoll;
+
 			sqd->sq_cpu = cpu;
 		} else {
 			sqd->sq_cpu = -1;
-- 
2.24.4