scsi: ufs: Add clock ungating to a separate workqueue

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UFS driver can receive a request during memory reclaim by kswapd.  So
when ufs driver puts the ungate work in queue, and if there are no idle
workers, kthreadd is invoked to create a new kworker. Since kswapd task
holds a mutex which kthreadd also needs, this can cause a deadlock
situation. So ungate work must be done in a separate work queue with
WQ_MEM_RECLAIM flag enabled.  Such a workqueue will have a rescue thread
which will be called when the above deadlock condition is possible.

Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

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Vijay Viswanath 2018-05-03 16:37:22 +05:30 • committed by Martin K. Petersen

parent 7f6ba4f12e

commit 10e5e37581

2 changed files with 11 additions and 1 deletions

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11

drivers/scsi/ufs/ufshcd.c

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1

drivers/scsi/ufs/ufshcd.h

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