scsi: qla2xxx: Fix response queue handler reading stale packets

scsi: qla2xxx: Fix response queue handler reading stale packets

[ Upstream commit b1f707146923335849fb70237eec27d4d1ae7d62 ]

On some platforms, the current logic of relying on finding new packet
solely based on signature pattern can lead to driver reading stale
packets. Though this is a bug in those platforms, reduce such exposures by
limiting reading packets until the IN pointer.

Two module parameters are introduced:

  ql2xrspq_follow_inptr:

    When set, on newer adapters that has queue pointer shadowing, look for
    response packets only until response queue in pointer.

    When reset, response packets are read based on a signature pattern
    logic (old way).

  ql2xrspq_follow_inptr_legacy:

    Like ql2xrspq_follow_inptr, but for those adapters where there is no
    queue pointer shadowing.

Link: https://lore.kernel.org/r/20220713052045.10683-5-njavali@marvell.com
Cc: stable@vger.kernel.org
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>