Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965949AbbD0Vns (ORCPT ); Mon, 27 Apr 2015 17:43:48 -0400 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:49642 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753283AbbD0Vc6 (ORCPT ); Mon, 27 Apr 2015 17:32:58 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Bart Van Assche , James Bottomley , Jiri Slaby Subject: [PATCH 3.12 30/83] Defer processing of REQ_PREEMPT requests for blocked devices Date: Mon, 27 Apr 2015 23:32:01 +0200 Message-Id: X-Mailer: git-send-email 2.3.5 In-Reply-To: <3426bb8de3a655aa6668e92ee92eb35f0db86582.1430159990.git.jslaby@suse.cz> References: <3426bb8de3a655aa6668e92ee92eb35f0db86582.1430159990.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3750 Lines: 89 From: Bart Van Assche 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit bba0bdd7ad4713d82338bcd9b72d57e9335a664b upstream. SCSI transport drivers and SCSI LLDs block a SCSI device if the transport layer is not operational. This means that in this state no requests should be processed, even if the REQ_PREEMPT flag has been set. This patch avoids that a rescan shortly after a cable pull sporadically triggers the following kernel oops: BUG: unable to handle kernel paging request at ffffc9001a6bc084 IP: [] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib] Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100) Call Trace: [] srp_post_send+0x65/0x70 [ib_srp] [] srp_queuecommand+0x1cf/0x3e0 [ib_srp] [] scsi_dispatch_cmd+0x101/0x280 [scsi_mod] [] scsi_request_fn+0x411/0x4d0 [scsi_mod] [] __blk_run_queue+0x27/0x30 [] blk_execute_rq_nowait+0x82/0x110 [] blk_execute_rq+0x62/0xf0 [] scsi_execute+0xe8/0x190 [scsi_mod] [] scsi_execute_req+0xa3/0x130 [scsi_mod] [] scsi_probe_lun+0x17a/0x450 [scsi_mod] [] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod] [] __scsi_scan_target+0xdf/0x1f0 [scsi_mod] [] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod] [] scsi_scan+0xdb/0xe0 [scsi_mod] [] store_scan+0x13/0x20 [scsi_mod] [] sysfs_write_file+0xcb/0x160 [] vfs_write+0xce/0x140 [] sys_write+0x53/0xa0 [] system_call_fastpath+0x16/0x1b [<00007f611c9d9300>] 0x7f611c9d92ff Reported-by: Max Gurtuvoy Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Signed-off-by: James Bottomley Signed-off-by: Jiri Slaby --- drivers/scsi/scsi_lib.c | 4 +++- include/linux/blk_types.h | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index ad43b987bc57..0c6a2660d1d5 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1258,9 +1258,11 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) "rejecting I/O to dead device\n"); ret = BLKPREP_KILL; break; - case SDEV_QUIESCE: case SDEV_BLOCK: case SDEV_CREATED_BLOCK: + ret = BLKPREP_DEFER; + break; + case SDEV_QUIESCE: /* * If the devices is blocked we defer normal commands. */ diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index fa1abeb45b76..49c48dda162d 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -170,7 +170,9 @@ enum rq_flag_bits { __REQ_ELVPRIV, /* elevator private data attached */ __REQ_FAILED, /* set if the request failed */ __REQ_QUIET, /* don't worry about errors */ - __REQ_PREEMPT, /* set for "ide_preempt" requests */ + __REQ_PREEMPT, /* set for "ide_preempt" requests and also + for requests for which the SCSI "quiesce" + state must be ignored. */ __REQ_ALLOCED, /* request came from our alloc pool */ __REQ_COPY_USER, /* contains copies of user pages */ __REQ_FLUSH_SEQ, /* request for flush sequence */ -- 2.3.5 -- 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/