Zachary Hays c4609e81e0 mmc: block: handle complete_work on separate workqueue ... commit dcf6e2e38a upstream. The kblockd workqueue is created with the WQ_MEM_RECLAIM flag set. This generates a rescuer thread for that queue that will trigger when the CPU is under heavy load and collect the uncompleted work. In the case of mmc, this creates the possibility of a deadlock when there are multiple partitions on the device as other blk-mq work is also run on the same queue. For example: - worker 0 claims the mmc host to work on partition 1 - worker 1 attempts to claim the host for partition 2 but has to wait for worker 0 to finish - worker 0 schedules complete_work to release the host - rescuer thread is triggered after time-out and collects the dangling work - rescuer thread attempts to complete the work in order starting with claim host - the task to release host is now blocked by a task to claim it and will never be called The above results in multiple hung tasks that lead to failures to mount partitions. Handling complete_work on a separate workqueue avoids this by keeping the work completion tasks separate from the other blk-mq work. This allows the host to be released without getting blocked by other tasks attempting to claim the host. Signed-off-by: Zachary Hays <zhays@lexmark.com> Fixes: 81196976ed ("mmc: block: Add blk-mq support") Cc: <stable@vger.kernel.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-02-20 10:25:46 +01:00
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card.h	mmc: block: handle complete_work on separate workqueue	2019-02-20 10:25:46 +01:00
core.h	mmc: core: Export a function mmc_sw_reset() to allow soft reset of cards	2018-05-08 09:33:42 +02:00
host.h	mmc: core: Drop the unused mmc_power_save|restore_host()	2018-07-16 11:21:45 +02:00
mmc.h	mmc: core: Adjust and reuse the macro of R1_STATUS(x)	2018-07-16 11:21:45 +02:00
pm.h
sd.h
sdhci-pci-data.h	MMC core:	2017-11-13 10:17:35 -08:00
sdio.h
sdio_func.h	mmc: sdio: fix alignment issue in struct sdio_func	2017-04-18 19:18:07 +02:00
sdio_ids.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2018-06-06 18:39:49 -07:00
sh_mmcif.h
slot-gpio.h	mmc: slot-gpio: Add a function to enable/disable card detect IRQ wakeup	2018-03-05 13:04:32 +01:00