scsi/qla1280: Remove stale comment about mmiowb()

All mmiowb() invocations have been removed, so there's no need to keep
banging on about it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index 93acbc5..327eff6 100644 (file)
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -3363,16 +3363,6 @@ qla1280_isp_cmd(struct scsi_qla_host *ha)
 
        /*
         * Update request index to mailbox4 (Request Queue In).
-        * The mmiowb() ensures that this write is ordered with writes by other
-        * CPUs.  Without the mmiowb(), it is possible for the following:
-        *    CPUA posts write of index 5 to mailbox4
-        *    CPUA releases host lock
-        *    CPUB acquires host lock
-        *    CPUB posts write of index 6 to mailbox4
-        *    On PCI bus, order reverses and write of 6 posts, then index 5,
-        *       causing chip to issue full queue of stale commands
-        * The mmiowb() prevents future writes from crossing the barrier.
-        * See Documentation/driver-api/device-io.rst for more information.
         */
        WRT_REG_WORD(&reg->mailbox4, ha->req_ring_index);