Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965462AbXAXBHF (ORCPT ); Tue, 23 Jan 2007 20:07:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965461AbXAXBHF (ORCPT ); Tue, 23 Jan 2007 20:07:05 -0500 Received: from 67.111.72.3.ptr.us.xo.net ([67.111.72.3]:50833 "EHLO nonameb.ptu.promise.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965458AbXAXBHD (ORCPT ); Tue, 23 Jan 2007 20:07:03 -0500 X-Greylist: delayed 859 seconds by postgrey-1.27 at vger.kernel.org; Tue, 23 Jan 2007 20:07:01 EST Date: Tue, 23 Jan 2007 16:53:44 -0800 From: "Ed Lin" To: "linux-scsi" Cc: "linux-kernel" , "james.Bottomley" , "jeff" , "promise_linux" Subject: [patch] scsi: use lock per host instead of per device for shared queue tag host X-mailer: Foxmail 5.0 [en] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Message-ID: X-OriginalArrivalTime: 24 Jan 2007 00:53:52.0140 (UTC) FILETIME=[1DB1ACC0:01C73F52] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2620 Lines: 66 The block layer uses lock to protect request queue. Every scsi device has a unique request queue, and queue lock is the default lock in struct request_queue. This is good for normal cases. But for a host with shared queue tag (e.g. stex controllers), a queue lock per device means the shared queue tag is not protected when multiple devices are accessed at a same time. This patch is a simple fix for this situation by introducing a host queue lock to protect shared queue tag. Without this patch we will see various kernel panics (including the BUG() and kernel errors in blk_queue_start_tag and blk_queue_end_tag of ll_rw_blk.c) when accessing different devices simultaneously (e.g. copying big file from one device to another in smp kernels). This is against kernel 2.6.20-rc5. Signed-off-by: Ed Lin --- drivers/scsi/scsi_lib.c | 2 +- drivers/scsi/stex.c | 2 ++ include/scsi/scsi_host.h | 3 +++ 3 files changed, 6 insertions(+), 1 deletion(-) diff -purN a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c --- a/drivers/scsi/scsi_lib.c 2007-01-23 14:40:28.000000000 -0800 +++ b/drivers/scsi/scsi_lib.c 2007-01-23 14:46:43.000000000 -0800 @@ -1574,7 +1574,7 @@ struct request_queue *__scsi_alloc_queue { struct request_queue *q; - q = blk_init_queue(request_fn, NULL); + q = blk_init_queue(request_fn, shost->req_q_lock); if (!q) return NULL; diff -purN a/drivers/scsi/stex.c b/drivers/scsi/stex.c --- a/drivers/scsi/stex.c 2007-01-23 14:40:28.000000000 -0800 +++ b/drivers/scsi/stex.c 2007-01-23 14:48:59.000000000 -0800 @@ -1254,6 +1254,8 @@ stex_probe(struct pci_dev *pdev, const s if (err) goto out_free_irq; + spin_lock_init(&host->__req_q_lock); + host->req_q_lock = &host->__req_q_lock; err = scsi_init_shared_tag_map(host, host->can_queue); if (err) { printk(KERN_ERR DRV_NAME "(%s): init shared queue failed\n", diff -purN a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h --- a/include/scsi/scsi_host.h 2007-01-23 14:40:29.000000000 -0800 +++ b/include/scsi/scsi_host.h 2007-01-23 14:57:04.000000000 -0800 @@ -508,6 +508,9 @@ struct Scsi_Host { spinlock_t default_lock; spinlock_t *host_lock; + spinlock_t __req_q_lock; + spinlock_t *req_q_lock;/* protect shared block queue tag */ + struct mutex scan_mutex;/* serialize scanning activity */ struct list_head eh_cmd_q; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/