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authorMatthew R. Ochs <mrochs@linux.vnet.ibm.com>2015-10-21 22:14:56 +0200
committerJames Bottomley <JBottomley@Odin.com>2015-10-30 09:17:56 +0100
commit8e78262328ecfbe9d72ac40328ecf5e7ff6fc3bf (patch)
tree6e276b9922999cb62d424b22643382afc5ab59d8 /drivers/scsi/pas16.c
parentcxlflash: Fix MMIO and endianness errors (diff)
downloadlinux-8e78262328ecfbe9d72ac40328ecf5e7ff6fc3bf.tar.xz
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cxlflash: Fix to prevent EEH recovery failure
The process_sense() routine can perform a read capacity which can take some time to complete. If an EEH occurs while waiting on the read capacity, the EEH handler will wait to obtain the context's mutex in order to put the context in an error state. The EEH handler will sit and wait until the context is free, but this wait can potentially last forever (deadlock) if the scsi_execute() that performs the read capacity experiences a timeout and calls into the reset callback. When that occurs, the reset callback sees that the device is already being reset and waits for the reset to complete. This leaves two threads waiting on the other. To address this issue, make the context unavailable to new, non-system owned threads and release the context while calling into process_sense(). After returning from process_sense() the context mutex is reacquired and the context is made available again. The context can be safely moved to the error state if needed during the unavailable window as no other threads will hold its reference. Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com> Reviewed-by: Brian King <brking@linux.vnet.ibm.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
Diffstat (limited to 'drivers/scsi/pas16.c')
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