io_uring: use cpu_online() to check p->sq_thread_cpu instead of cpu_possible()
authorShenghui Wang <shhuiw@foxmail.com>
Tue, 7 May 2019 08:03:19 +0000 (16:03 +0800)
committerJens Axboe <axboe@kernel.dk>
Tue, 7 May 2019 14:41:26 +0000 (08:41 -0600)
commit7889f44dd9cee15aff1c3f7daf81ca4dfed48fc7
tree02b01ac768591a2f08f4b599dfc2305b67ff4022
parentefeb862bd5bc001636e690debf6f9fbba98e5bfd
io_uring: use cpu_online() to check p->sq_thread_cpu instead of cpu_possible()

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>
fs/io_uring.c