From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uma Krishnan Subject: [PATCH 1/3] cxlflash: Fix to drain operations from previous reset Date: Wed, 15 Jun 2016 18:49:20 -0500 Message-ID: <1466034560-17864-1-git-send-email-ukrishn@linux.vnet.ibm.com> References: <1466034460-17797-1-git-send-email-ukrishn@linux.vnet.ibm.com> Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:10670 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932321AbcFOXti (ORCPT ); Wed, 15 Jun 2016 19:49:38 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5FNmoLj004683 for ; Wed, 15 Jun 2016 19:49:37 -0400 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0b-001b2d01.pphosted.com with ESMTP id 23jggtyweh-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 15 Jun 2016 19:49:37 -0400 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 15 Jun 2016 17:49:37 -0600 In-Reply-To: <1466034460-17797-1-git-send-email-ukrishn@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org, James Bottomley , "Martin K. Petersen" , "Matthew R. Ochs" , "Manoj N. Kumar" Cc: Brian King , linuxppc-dev@lists.ozlabs.org, Ian Munsie , Andrew Donnellan , Frederic Barrat , Christophe Lombard From: "Manoj N. Kumar" While running 'sg_reset -H' in a loop with a user-space application active, hit the following exception: cpu 0x2: Vector: 300 (Data Access) pc: : afu_attach+0x50/0x240 [cxlflash] lr: : cxlflash_afu_recover+0x3dc/0x7d0 [cxlflash] pid = 20365, comm = run_block_fvt Linux version 4.5.0-491-26f710d+ cxlflash_afu_recover+0x3dc/0x7d0 [cxlflash] cxlflash_ioctl+0x5a8/0x6f0 [cxlflash] scsi_ioctl+0x3b0/0x4c0 sd_ioctl+0x110/0x190 blkdev_ioctl+0x28c/0xc20 block_ioctl+0xa4/0xd0 do_vfs_ioctl+0xd8/0x8c0 SyS_ioctl+0xd4/0xf0 system_call+0x38/0xb4 The problem here is that the problem space area is unmapped while the application issues the DK_CXLFLASH_RECOVER_AFU ioctl. This is the order I observe: proc1 proc2 1) sg_reset 2) ioctl(DK_CXLFLASH_RECOVER_AFU) 3) sg_reset again causing a PSA unmap 4) continues RECOVER_AFU processing The resolution to this problem is to have the reset handler drain all outstanding user space initiated ioctls before proceeding. It is safe to drain after the state has been changed to STATE_RESET. Also since drain_ioctls() was static, it had to be moved up a bit to be before cxlflash_eh_host_reset_handler(). Signed-off-by: Manoj N. Kumar --- drivers/scsi/cxlflash/main.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index 8fb9643..f1f977f 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -1916,6 +1916,19 @@ static int afu_reset(struct cxlflash_cfg *cfg) } /** + * drain_ioctls() - wait until all currently executing ioctls have completed + * @cfg: Internal structure associated with the host. + * + * Obtain write access to read/write semaphore that wraps ioctl + * handling to 'drain' ioctls currently executing. + */ +static void drain_ioctls(struct cxlflash_cfg *cfg) +{ + down_write(&cfg->ioctl_rwsem); + up_write(&cfg->ioctl_rwsem); +} + +/** * cxlflash_eh_device_reset_handler() - reset a single LUN * @scp: SCSI command to send. * @@ -1986,6 +1999,7 @@ static int cxlflash_eh_host_reset_handler(struct scsi_cmnd *scp) switch (cfg->state) { case STATE_NORMAL: cfg->state = STATE_RESET; + drain_ioctls(cfg); cxlflash_mark_contexts_error(cfg); rcr = afu_reset(cfg); if (rcr) { @@ -2504,19 +2518,6 @@ out_remove: } /** - * drain_ioctls() - wait until all currently executing ioctls have completed - * @cfg: Internal structure associated with the host. - * - * Obtain write access to read/write semaphore that wraps ioctl - * handling to 'drain' ioctls currently executing. - */ -static void drain_ioctls(struct cxlflash_cfg *cfg) -{ - down_write(&cfg->ioctl_rwsem); - up_write(&cfg->ioctl_rwsem); -} - -/** * cxlflash_pci_error_detected() - called when a PCI error is detected * @pdev: PCI device struct. * @state: PCI channel state. -- 2.1.0