From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Matthew R. Ochs" Subject: [PATCH v4 04/32] cxlflash: Fix potential oops following LUN removal Date: Fri, 25 Sep 2015 18:13:26 -0500 Message-ID: <1443222806-9072-1-git-send-email-mrochs@linux.vnet.ibm.com> References: <1443222593-8828-1-git-send-email-mrochs@linux.vnet.ibm.com> Return-path: Received: from e32.co.us.ibm.com ([32.97.110.150]:42544 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755180AbbIYXPG (ORCPT ); Fri, 25 Sep 2015 19:15:06 -0400 Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 25 Sep 2015 17:15:06 -0600 Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 046D51FF0045 for ; Fri, 25 Sep 2015 17:06:12 -0600 (MDT) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8PNDgKG8585664 for ; Fri, 25 Sep 2015 16:13:50 -0700 Received: from d03av02.boulder.ibm.com (localhost [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8PNESiY025652 for ; Fri, 25 Sep 2015 17:14:30 -0600 In-Reply-To: <1443222593-8828-1-git-send-email-mrochs@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 , "Nicholas A. Bellinger" , Brian King , Ian Munsie , Daniel Axtens , Andrew Donnellan , Tomas Henzl , David Laight Cc: Michael Neuling , linuxppc-dev@lists.ozlabs.org, "Manoj N. Kumar" When a LUN is removed, the sdev that is associated with the LUN remains intact until its reference count drops to 0. In order to prevent an sdev from being removed while a context is still associated with it, obtain an additional reference per-context for each LUN attached to the context. This resolves a potential Oops in the release handler when a dealing with a LUN that has already been removed. Signed-off-by: Matthew R. Ochs Signed-off-by: Manoj N. Kumar Reviewed-by: Brian King --- drivers/scsi/cxlflash/superpipe.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c index 4e44a48..ffa68cc 100644 --- a/drivers/scsi/cxlflash/superpipe.c +++ b/drivers/scsi/cxlflash/superpipe.c @@ -880,6 +880,9 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev, sys_close(lfd); } + /* Release the sdev reference that bound this LUN to the context */ + scsi_device_put(sdev); + out: if (put_ctx) put_context(ctxi); @@ -1287,11 +1290,17 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, } } + rc = scsi_device_get(sdev); + if (unlikely(rc)) { + dev_err(dev, "%s: Unable to get sdev reference!\n", __func__); + goto out; + } + lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL); if (unlikely(!lun_access)) { dev_err(dev, "%s: Unable to allocate lun_access!\n", __func__); rc = -ENOMEM; - goto out; + goto err0; } lun_access->lli = lli; @@ -1311,21 +1320,21 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, dev_err(dev, "%s: Could not initialize context %p\n", __func__, ctx); rc = -ENODEV; - goto err0; + goto err1; } ctxid = cxl_process_element(ctx); if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) { dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid); rc = -EPERM; - goto err1; + goto err2; } file = cxl_get_fd(ctx, &cfg->cxl_fops, &fd); if (unlikely(fd < 0)) { rc = -ENODEV; dev_err(dev, "%s: Could not get file descriptor\n", __func__); - goto err1; + goto err2; } /* Translate read/write O_* flags from fcntl.h to AFU permission bits */ @@ -1335,7 +1344,7 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, if (unlikely(!ctxi)) { dev_err(dev, "%s: Failed to create context! (%d)\n", __func__, ctxid); - goto err2; + goto err3; } work = &ctxi->work; @@ -1346,13 +1355,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, if (unlikely(rc)) { dev_dbg(dev, "%s: Could not start context rc=%d\n", __func__, rc); - goto err3; + goto err4; } rc = afu_attach(cfg, ctxi); if (unlikely(rc)) { dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc); - goto err4; + goto err5; } /* @@ -1388,13 +1397,13 @@ out: __func__, ctxid, fd, attach->block_size, rc, attach->last_lba); return rc; -err4: +err5: cxl_stop_context(ctx); -err3: +err4: put_context(ctxi); destroy_context(cfg, ctxi); ctxi = NULL; -err2: +err3: /* * Here, we're overriding the fops with a dummy all-NULL fops because * fput() calls the release fop, which will cause us to mistakenly @@ -1406,10 +1415,12 @@ err2: fput(file); put_unused_fd(fd); fd = -1; -err1: +err2: cxl_release_context(ctx); -err0: +err1: kfree(lun_access); +err0: + scsi_device_put(sdev); goto out; } -- 2.1.0