Minchan Kim a0c516cbfc zram: don't grab mutex in zram_slot_free_noity ... [1] introduced down_write in zram_slot_free_notify to prevent race between zram_slot_free_notify and zram_bvec_[read|write]. The race could happen if somebody who has right permission to open swap device is reading swap device while it is used by swap in parallel. However, zram_slot_free_notify is called with holding spin_lock of swap layer so we shouldn't avoid holing mutex. Otherwise, lockdep warns it. This patch adds new list to handle free slot and workqueue so zram_slot_free_notify just registers slot index to be freed and registers the request to workqueue. If workqueue is expired, it holds mutex_lock so there is no problem any more. If any I/O is issued, zram handles pending slot-free request caused by zram_slot_free_notify right before handling issued request because workqueue wouldn't be expired yet so zram I/O request handling function can miss it. Lastly, when zram is reset, flush_work could handle all of pending free request so we shouldn't have memory leak. NOTE: If zram_slot_free_notify's kmalloc with GFP_ATOMIC would be failed, the slot will be freed when next write I/O write the slot. [1] [57ab0485, zram: use zram->lock to protect zram_free_page() in swap free notify path] * from v2 * refactoring * from v1 * totally redesign Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-08-12 15:25:00 -07:00
..
Kconfig	staging: Add angle bracket before and after the URL	2013-01-07 14:56:04 -08:00
Makefile	zram: remove zram_sysfs file (v2)	2013-06-24 15:59:03 -07:00
zram_drv.c	zram: don't grab mutex in zram_slot_free_noity	2013-08-12 15:25:00 -07:00
zram_drv.h	zram: don't grab mutex in zram_slot_free_noity	2013-08-12 15:25:00 -07:00
zram.txt	zram: force disksize setting before using zram	2013-02-03 17:52:49 -08:00