Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756140AbcJFXlT (ORCPT ); Thu, 6 Oct 2016 19:41:19 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:45970 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415AbcJFXlJ (ORCPT ); Thu, 6 Oct 2016 19:41:09 -0400 To: "James E.J. Bottomley" , "Martin K. Petersen" Cc: Michael Schmitz , Ondrej Zary , , Message-Id: <01e95bb5b972d922af8415831ce23b8fbc516766.1475791899.git.fthain@telegraphics.com.au> In-Reply-To: References: From: Finn Thain Subject: [PATCH v2 03/12] scsi/atari_scsi: Make device register accessors re-enterant Date: Thu, 6 Oct 2016 19:41:07 -0400 (EDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1439 Lines: 47 This patch fixes an old bug: accesses to device registers from the interrupt handler (after reselection, DMA completion etc.) could mess up a device register access elsewhere, if the latter takes place outside of an irq lock (during selection etc.). Signed-off-by: Finn Thain Reviewed-by: Hannes Reinecke --- drivers/scsi/atari_scsi.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c index a59ad94..862f30c 100644 --- a/drivers/scsi/atari_scsi.c +++ b/drivers/scsi/atari_scsi.c @@ -670,14 +670,26 @@ static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value) static unsigned char atari_scsi_falcon_reg_read(unsigned char reg) { - dma_wd.dma_mode_status= (u_short)(0x88 + reg); - return (u_char)dma_wd.fdc_acces_seccount; + unsigned long flags; + unsigned char result; + + reg += 0x88; + local_irq_save(flags); + dma_wd.dma_mode_status = (u_short)reg; + result = (u_char)dma_wd.fdc_acces_seccount; + local_irq_restore(flags); + return result; } static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value) { - dma_wd.dma_mode_status = (u_short)(0x88 + reg); + unsigned long flags; + + reg += 0x88; + local_irq_save(flags); + dma_wd.dma_mode_status = (u_short)reg; dma_wd.fdc_acces_seccount = (u_short)value; + local_irq_restore(flags); } -- 2.7.3