aacraid: Relinquish CPU during timeout wait
commit07beca2be24cc710461c0b131832524c9ee08910
authorRaghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Tue, 26 Apr 2016 06:31:26 +0000 (25 23:31 -0700)
committerMartin K. Petersen <martin.petersen@oracle.com>
Fri, 29 Apr 2016 23:08:24 +0000 (29 19:08 -0400)
treee47525202f3a89f258e5d376de8987f13dc1829c
parent116d77fea02e2a5aded7d29ba4c692774cb339f1
aacraid: Relinquish CPU during timeout wait

aac_fib_send has a special function case for initial commands during
driver initialization using wait < 0(pseudo sync mode). In this case,
the command does not sleep but rather spins checking for timeout.This
loop is calls cpu_relax() in an attempt to allow other processes/threads
to use the CPU, but this function does not relinquish the CPU and so the
command will hog the processor. This was observed in a KDUMP
"crashkernel" and that prevented the "command thread" (which is
responsible for completing the command from being timed out) from
starting because it could not get the CPU.

Fixed by replacing "cpu_relax()" call with "schedule()"
Cc: stable@vger.kernel.org
Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
drivers/scsi/aacraid/commsup.c