aacraid: Relinquish CPU during timeout wait
authorRaghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Tue, 26 Apr 2016 06:31:26 +0000 (23:31 -0700)
committerSasha Levin <sasha.levin@oracle.com>
Fri, 3 Jun 2016 23:15:37 +0000 (19:15 -0400)
commite452f7382f5715d7d8b1d5f1129ded8870eaed5e
tree41ac330a4dddce0680eef9f32343d25cafe27e71
parent660cd2235c5ac7a4d3aa5c3370b63124fb50cf81
aacraid: Relinquish CPU during timeout wait

[ Upstream commit 07beca2be24cc710461c0b131832524c9ee08910 ]

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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
drivers/scsi/aacraid/commsup.c