From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753277AbbKOCHh (ORCPT ); Sat, 14 Nov 2015 21:07:37 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35278 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752269AbbKOCEv (ORCPT ); Sat, 14 Nov 2015 21:04:51 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Christoph Hellwig" , "Adam Radford" , "=?UTF-8?Q?T=C3=B3th=20?=Attila" , "James Bottomley" Date: Sun, 15 Nov 2015 01:45:45 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 27/60] 3w-9xxx: don't unmap bounce buffered commands In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.73-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Hellwig commit 15e3d5a285ab9283136dba34bbf72886d9146706 upstream. 3w controller don't dma map small single SGL entry commands but instead bounce buffer them. Add a helper to identify these commands and don't call scsi_dma_unmap for them. Based on an earlier patch from James Bottomley. Fixes: 118c85 ("3w-9xxx: fix command completion race") Reported-by: Tóth Attila Tested-by: Tóth Attila Signed-off-by: Christoph Hellwig Acked-by: Adam Radford Signed-off-by: James Bottomley Signed-off-by: Ben Hutchings --- drivers/scsi/3w-9xxx.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) --- a/drivers/scsi/3w-9xxx.c +++ b/drivers/scsi/3w-9xxx.c @@ -225,6 +225,17 @@ static const struct file_operations twa_ .llseek = noop_llseek, }; +/* + * The controllers use an inline buffer instead of a mapped SGL for small, + * single entry buffers. Note that we treat a zero-length transfer like + * a mapped SGL. + */ +static bool twa_command_mapped(struct scsi_cmnd *cmd) +{ + return scsi_sg_count(cmd) != 1 || + scsi_bufflen(cmd) >= TW_MIN_SGL_LENGTH; +} + /* This function will complete an aen request from the isr */ static int twa_aen_complete(TW_Device_Extension *tw_dev, int request_id) { @@ -1351,7 +1362,8 @@ static irqreturn_t twa_interrupt(int irq } /* Now complete the io */ - scsi_dma_unmap(cmd); + if (twa_command_mapped(cmd)) + scsi_dma_unmap(cmd); cmd->scsi_done(cmd); tw_dev->state[request_id] = TW_S_COMPLETED; twa_free_request_id(tw_dev, request_id); @@ -1594,7 +1606,8 @@ static int twa_reset_device_extension(TW struct scsi_cmnd *cmd = tw_dev->srb[i]; cmd->result = (DID_RESET << 16); - scsi_dma_unmap(cmd); + if (twa_command_mapped(cmd)) + scsi_dma_unmap(cmd); cmd->scsi_done(cmd); } } @@ -1777,12 +1790,14 @@ static int twa_scsi_queue_lck(struct scs retval = twa_scsiop_execute_scsi(tw_dev, request_id, NULL, 0, NULL); switch (retval) { case SCSI_MLQUEUE_HOST_BUSY: - scsi_dma_unmap(SCpnt); + if (twa_command_mapped(SCpnt)) + scsi_dma_unmap(SCpnt); twa_free_request_id(tw_dev, request_id); break; case 1: SCpnt->result = (DID_ERROR << 16); - scsi_dma_unmap(SCpnt); + if (twa_command_mapped(SCpnt)) + scsi_dma_unmap(SCpnt); done(SCpnt); tw_dev->state[request_id] = TW_S_COMPLETED; twa_free_request_id(tw_dev, request_id); @@ -1843,8 +1858,7 @@ static int twa_scsiop_execute_scsi(TW_De /* Map sglist from scsi layer to cmd packet */ if (scsi_sg_count(srb)) { - if ((scsi_sg_count(srb) == 1) && - (scsi_bufflen(srb) < TW_MIN_SGL_LENGTH)) { + if (!twa_command_mapped(srb)) { if (srb->sc_data_direction == DMA_TO_DEVICE || srb->sc_data_direction == DMA_BIDIRECTIONAL) scsi_sg_copy_to_buffer(srb, @@ -1917,7 +1931,7 @@ static void twa_scsiop_execute_scsi_comp { struct scsi_cmnd *cmd = tw_dev->srb[request_id]; - if (scsi_bufflen(cmd) < TW_MIN_SGL_LENGTH && + if (!twa_command_mapped(cmd) && (cmd->sc_data_direction == DMA_FROM_DEVICE || cmd->sc_data_direction == DMA_BIDIRECTIONAL)) { if (scsi_sg_count(cmd) == 1) {