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scsi/qla1280: Remove stale comment about mmiowb()

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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>
This commit is contained in:
Will Deacon 2019-02-22 17:18:02 +00:00
parent fb24ea52f7
commit 161861a4c8
1 changed files with 0 additions and 10 deletions
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10
drivers/scsi/qla1280.c
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@ -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);