3.18-stable review patch. If anyone has any objections, please let me know.
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From: James Smart jsmart2021@gmail.com
[ Upstream commit 04673e38f56b30cd39b1fa0f386137d818b17781 ]
The driver controls when the hardware sends completions that communicate consumption of elements from the WQ. This is done by setting a WQEC bit on a WQE.
The current driver sets it on every Nth WQE posting. However, the driver isn't clearing the bit if the WQE is reused. Thus, if the queue depth isn't evenly divisible by N, with enough time, it can be set on every element, creating a lot of overhead and risking CQ full conditions.
Correct by clearing the bit when not setting it on an Nth element.
Signed-off-by: Dick Kennedy dick.kennedy@broadcom.com Signed-off-by: James Smart james.smart@broadcom.com Reviewed-by: Hannes Reinecke hare@suse.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/scsi/lpfc/lpfc_sli.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -115,6 +115,8 @@ lpfc_sli4_wq_put(struct lpfc_queue *q, u /* set consumption flag every once in a while */ if (!((q->host_index + 1) % q->entry_repost)) bf_set(wqe_wqec, &wqe->generic.wqe_com, 1); + else + bf_set(wqe_wqec, &wqe->generic.wqe_com, 0); if (q->phba->sli3_options & LPFC_SLI4_PHWQ_ENABLED) bf_set(wqe_wqid, &wqe->generic.wqe_com, q->queue_id); lpfc_sli_pcimem_bcopy(wqe, temp_wqe, q->entry_size);