tree e4e80fb4a6929c94e99b47f2a2539b770b5dd8ce
parent 6bf3b630d0a733b74f7167a1cfac457358e67074
author Raghava Aditya Renukunta <raghavaaditya.renukunta@pmcs.com> 1454540760 -0800
committer Martin K. Petersen <martin.petersen@oracle.com> 1456280822 -0500

aacraid: Fix RRQ overload

The driver utilizes an array of atomic variables to keep track of IO
submissions to each vector. To submit an IO multiple threads iterate
through the array to find a vector which has empty slots to send an
IO. The reading and updating of the variable is not atomic, causing race
conditions when a thread uses a full vector to submit an IO.

Fixed by mapping each FIB to a vector, the submission path then uses
said vector to submit IO thereby removing the possibly of a race
condition.The vector assignment is started from 1 since vector 0 is
reserved for the use of AIF management FIBS.If the number of MSIx
vectors is 1 (MSI or INTx mode) then all the fibs are allocated to
vector 0.

Fixes: 495c0217 "aacraid: MSI-x support"
Cc: stable@vger.kernel.org # v4.1

Signed-off-by: Raghava Aditya Renukunta <raghavaaditya.renukunta@pmcs.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>