On Mon, Oct 17, 2016 at 02:19:47PM -0400, Jeff Moyer wrote:
> This ends up being a call to __sb_end_write:
> void __sb_end_write(struct super_block *sb, int level)
> percpu_up_read(sb->s_writers.rw_sem + level-1);
> Nothing guarantees that submission and completion happen on the same
> CPU. Is this safe?
Good point. From my reading of the percpu_rwsem implementation it
is not safe to release it from a different CPU. Which makes me
wonder how we can protect aio writes properly here..