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Commit f2233a33 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Martin K. Petersen
Browse files

scsi: ipr: Eliminate duplicate barriers 



Driver does both wmb() and writel(). The latter already has a barrier
on some architectures like arm64. This ends up with CPU observing two
barriers back to back before executing the register write.

Drivers should generally assume that the barrier implied by writel() is
sufficient for ordering DMA. Remove the extraneous wmb() before it.

[mkp: Squashed Arnd's and Sinan's patches]

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Reported-by: default avatarSinan Kaya <okaya@codeaurora.org>
Acked-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 6c3796d1

drivers/scsi/ipr.c

+0 −2
Original line number Diff line number Diff line
@@ -760,7 +760,6 @@ static void ipr_mask_and_clear_interrupts(struct ipr_ioa_cfg *ioa_cfg, 
		ioa_cfg->hrrq[i].allow_interrupts = 0;

		spin_unlock(&ioa_cfg->hrrq[i]._lock);

	}

	wmb();



	/* Set interrupt mask to stop all new interrupts */

	if (ioa_cfg->sis64)
@@ -8403,7 +8402,6 @@ static int ipr_reset_enable_ioa(struct ipr_cmnd *ipr_cmd) 
		ioa_cfg->hrrq[i].allow_interrupts = 1;

		spin_unlock(&ioa_cfg->hrrq[i]._lock);

	}

	wmb();

	if (ioa_cfg->sis64) {

		/* Set the adapter to the correct endian mode. */

		writel(IPR_ENDIAN_SWAP_KEY, ioa_cfg->regs.endian_swap_reg);