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[v4,4/7] scsi: lpfc: Eliminate duplicate barriers on weakly-ordered archs

Message ID 1521514207-10695-5-git-send-email-okaya@codeaurora.org (mailing list archive)
State New, archived
Headers show

Commit Message

Sinan Kaya March 20, 2018, 2:50 a.m. UTC 
Code includes barrier() followed by writel(). writel() already has a
barrier
on some architectures like arm64.

This ends up CPU observing two barriers back to back before executing the
register write.

Since code already has an explicit barrier call, changing writel() to
writel_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/scsi/lpfc/lpfc_sli.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 5f5528a..7dae7d3 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -1647,7 +1647,7 @@  lpfc_sli_update_full_ring(struct lpfc_hba *phba, struct lpfc_sli_ring *pring)
 	 * Set ring 'ringno' to SET R0CE_REQ in Chip Att register.
 	 * The HBA will tell us when an IOCB entry is available.
 	 */
-	writel((CA_R0ATT|CA_R0CE_REQ) << (ringno*4), phba->CAregaddr);
+	writel_relaxed((CA_R0ATT|CA_R0CE_REQ) << (ringno*4), phba->CAregaddr);
 	readl(phba->CAregaddr); /* flush */
 
 	pring->stats.iocb_cmd_full++;
@@ -1672,7 +1672,7 @@  lpfc_sli_update_ring(struct lpfc_hba *phba, struct lpfc_sli_ring *pring)
 	 */
 	if (!(phba->sli3_options & LPFC_SLI3_CRP_ENABLED)) {
 		wmb();
-		writel(CA_R0ATT << (ringno * 4), phba->CAregaddr);
+		writel_relaxed(CA_R0ATT << (ringno * 4), phba->CAregaddr);
 		readl(phba->CAregaddr); /* flush */
 	}
 }