From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262770AbVENN6W (ORCPT ); Sat, 14 May 2005 09:58:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262767AbVENN6T (ORCPT ); Sat, 14 May 2005 09:58:19 -0400 Received: from rproxy.gmail.com ([64.233.170.198]:52307 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S262640AbVENN5n (ORCPT ); Sat, 14 May 2005 09:57:43 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:cc:user-agent:content-type:references:in-reply-to:subject:message-id:date; b=hsCYJMYhp1kxbKpmSGmUTm4zJEktNZex9v2R71uukniJ3vanWtraA6twmjI8ngjm3W/uXVJ6fSZ7TlVJLm+HZgoX5iWsVAn32qGn1F7+D1mm9SyGAiFCZ7a8QoSc+sNKgkyCuDNkYPGot8L78a+TgWwdax1D3xjNW/YO+o/PVdY= From: Tejun Heo To: James.Bottomley@steeleye.com, axboe@suse.de, Christoph Hellwig Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org User-Agent: lksp 0.3 Content-Type: text/plain; charset=US-ASCII References: <20050514135610.81030F26@htj.dyndns.org> In-Reply-To: <20050514135610.81030F26@htj.dyndns.org> Subject: Re: [PATCH scsi-misc-2.6 01/04] scsi: consolidate error handling out of scsi_init_io() into scsi_prep_fn() Message-ID: <20050514135610.536D5170@htj.dyndns.org> Date: Sat, 14 May 2005 22:57:38 +0900 (KST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 01_scsi_reqfn_consolidate_error_handling.patch This patch fixes a queue stall bug which occurred when sgtable allocation failed and device_busy == 0. When scsi_init_io() returns BLKPREP_DEFER or BLKPREP_KILL, it's supposed to free resources itself. This patch consolidates defer and kill handling into scsi_prep_fn(). Note that this patch doesn't consolidate state defer/kill handlings in scsi_prep_fn() as all state checks will be moved into scsi_reques_fn() by the following reqfn_reimpl patch. ret value checking was changed to switch() as in James's patch. Also, kill: comment is copied from James's patch. Signed-off-by: Tejun Heo scsi_lib.c | 40 ++++++++++++++++++++++++++++------------ 1 files changed, 28 insertions(+), 12 deletions(-) Index: scsi-reqfn-export/drivers/scsi/scsi_lib.c =================================================================== --- scsi-reqfn-export.orig/drivers/scsi/scsi_lib.c 2005-05-14 22:35:18.000000000 +0900 +++ scsi-reqfn-export/drivers/scsi/scsi_lib.c 2005-05-14 22:35:18.000000000 +0900 @@ -977,9 +977,6 @@ static int scsi_init_io(struct scsi_cmnd printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, req->current_nr_sectors); - /* release the command and kill it */ - scsi_release_buffers(cmd); - scsi_put_command(cmd); return BLKPREP_KILL; } @@ -1147,18 +1144,24 @@ static int scsi_prep_fn(struct request_q * required). */ ret = scsi_init_io(cmd); - if (ret) /* BLKPREP_KILL return also releases the command */ - return ret; + switch (ret) { + case 0: + /* Successful initialization. */ + break; + case BLKPREP_DEFER: + goto defer; + default: + /* Unknown return value, fall through. */ + case BLKPREP_KILL: + goto kill; + } /* * Initialize the actual SCSI command for this request. */ drv = *(struct scsi_driver **)req->rq_disk->private_data; - if (unlikely(!drv->init_command(cmd))) { - scsi_release_buffers(cmd); - scsi_put_command(cmd); - return BLKPREP_KILL; - } + if (unlikely(!drv->init_command(cmd))) + goto kill; } /* @@ -1168,12 +1171,25 @@ static int scsi_prep_fn(struct request_q return BLKPREP_OK; defer: - /* If we defer, the elv_next_request() returns NULL, but the + /* + * If we defer, the elv_next_request() returns NULL, but the * queue must be restarted, so we plug here if no returning - * command will automatically do that. */ + * command will automatically do that. + */ if (sdev->device_busy == 0) blk_plug_device(q); return BLKPREP_DEFER; + + kill: + /* + * Here we have to release every resource associated with the + * request because this will complete at the request level + * (req->end_io), not the scsi command level, so no scsi + * routine will get to free the associated resources. + */ + scsi_release_buffers(cmd); + scsi_put_command(cmd); + return BLKPREP_KILL; } /*