sysfs handlers should be called under ->init_lock and are not supposed to
unlock it until return, otherwise e.g. a concurrent reset() can occur.
There is one handler that breaks that rule: recomp_algorithm_show().
Move ->init_lock handling outside of __comp_algorithm_show() (also drop it
and call zcomp_available_show() directly) so that the entire
recomp_algorithm_show() loop is protected by the lock, as opposed to
protecting individual iterations.
The patch does not need to go to -stable, as it does not fix any
runtime errors (at least I can't think of any). It makes
recomp_algorithm_show() "atomic" w.r.t. zram reset() (just like the
rest of zram sysfs show() handlers), that's a pretty minor change.
Link: https://lkml.kernel.org/r/20250805101946.1774112-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Seyediman Seyedarab <imandevel@gmail.com>
Suggested-by: Seyediman Seyedarab <imandevel@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
7cbce1eaeb