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io_uring: use cpu_online() to check p->sq_thread_cpu instead of cpu_possible()

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This issue is found by running liburing/test/io_uring_setup test.

When test run, the testcase "attempt to bind to invalid cpu" would not
pass with messages like:
   io_uring_setup(1, 0xbfc2f7c8), \
flags: IORING_SETUP_SQPOLL|IORING_SETUP_SQ_AFF, \
resv: 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000, \
sq_thread_cpu: 2
   expected -1, got 3
   FAIL

On my system, there is:
   CPU(s) possible : 0-3
   CPU(s) online   : 0-1
   CPU(s) offline  : 2-3
   CPU(s) present  : 0-1

The sq_thread_cpu 2 is offline on my system, so the bind should fail.
But cpu_possible() will pass the check. We shouldn't be able to bind
to an offline cpu. Use cpu_online() to do the check.

After the change, the testcase run as expected: EINVAL will be returned
for cpu offlined.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shenghui Wang 2019-05-07 16:03:19 +08:00 committed by Jens Axboe
parent efeb862bd5
commit 7889f44dd9
1 changed files with 1 additions and 1 deletions
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2
fs/io_uring.c
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@ -2471,7 +2471,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
nr_cpu_ids);
ret = -EINVAL;
if (!cpu_possible(cpu))
if (!cpu_online(cpu))
goto err;
ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,