Commits
Brian Norris committed fcf68f3c0bb
iio: fix sched WARNING "do not call blocking ops when !TASK_RUNNING" When using CONFIG_DEBUG_ATOMIC_SLEEP, the scheduler nicely points out that we're calling sleeping primitives within the wait_event loop, which means we might clobber the task state: [ 10.831289] do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffc00026b610>] [ 10.845531] ------------[ cut here ]------------ [ 10.850161] WARNING: at kernel/sched/core.c:7630 ... [ 12.164333] ---[ end trace 45409966a9a76438 ]--- [ 12.168942] Call trace: [ 12.171391] [<ffffffc00024ed44>] __might_sleep+0x64/0x90 [ 12.176699] [<ffffffc000954774>] mutex_lock_nested+0x50/0x3fc [ 12.182440] [<ffffffc0007b9424>] iio_kfifo_buf_data_available+0x28/0x4c [ 12.189043] [<ffffffc0007b76ac>] iio_buffer_ready+0x60/0xe0 [ 12.194608] [<ffffffc0007b7834>] iio_buffer_read_first_n_outer+0x108/0x1a8 [ 12.201474] [<ffffffc000370d48>] __vfs_read+0x58/0x114 [ 12.206606] [<ffffffc000371740>] vfs_read+0x94/0x118 [ 12.211564] [<ffffffc0003720f8>] SyS_read+0x64/0xb4 [ 12.216436] [<ffffffc000203cb4>] el0_svc_naked+0x24/0x28 To avoid this, we should (a la https://lwn.net/Articles/628628/) use the wait_woken() function, which avoids the nested sleeping while still handling races between waiting / wake-events. Signed-off-by: Brian Norris <briannorris@chromium.org> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Cc: <Stable@vger.kernel.org> # 3.19+ for introduction of wake_woken Signed-off-by: Jonathan Cameron <jic23@kernel.org>