Zachary Hays dcf6e2e38a mmc: block: handle complete_work on separate workqueue ... 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>		2019-02-08 12:24:17 +01:00
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block.c	mmc: block: handle complete_work on separate workqueue	2019-02-08 12:24:17 +01:00
block.h
bus.c
bus.h
card.h
core.c
core.h
debugfs.c
host.c	mmc: core: don't override the CD GPIO level when "cd-inverted" is set	2019-01-11 15:27:35 +01:00
host.h
Kconfig
Makefile
mmc_ops.c
mmc_ops.h
mmc_test.c
mmc.c
pwrseq_emmc.c
pwrseq_sd8787.c
pwrseq_simple.c
pwrseq.c
pwrseq.h
queue.c
queue.h
quirks.h
sd_ops.c
sd_ops.h
sd.c
sd.h
sdio_bus.c
sdio_bus.h
sdio_cis.c
sdio_cis.h
sdio_io.c
sdio_irq.c
sdio_ops.c
sdio_ops.h
sdio_uart.c
sdio.c
slot-gpio.c
slot-gpio.h