Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751922AbdGAP5L (ORCPT ); Sat, 1 Jul 2017 11:57:11 -0400 Received: from mga03.intel.com ([134.134.136.65]:9267 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751389AbdGAP5K (ORCPT ); Sat, 1 Jul 2017 11:57:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,293,1496127600"; d="scan'208";a="281035187" Subject: [PATCH] libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime From: Dan Williams To: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org, Toshi Kani Date: Sat, 01 Jul 2017 08:50:43 -0700 Message-ID: <149892424300.37698.9888818880178611728.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2888 Lines: 86 We need to hold a reference on the 'dirent' until we are sure there are no more notifications that will be sent. As noted in the new comments we take advantage of the fact that the references are taken and dropped under device_lock() and that nd_device_notify() holds device_lock() over new badblocks notifications. The notifications that happen when badblocks are cleared only occur while the device is active. Also take the opportunity to fix up the error messages to report the user visible effect of a sysfs_get_dirent() failure. Fixes: 975750a98c26 ("libnvdimm, pmem: Add sysfs notifications to badblocks") Cc: Toshi Kani Signed-off-by: Dan Williams --- drivers/nvdimm/pmem.c | 16 ++++++++++++---- drivers/nvdimm/region.c | 13 +++++++++---- 2 files changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 34189a145ac6..4a9cffc14512 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -382,10 +382,8 @@ static int pmem_attach_disk(struct device *dev, pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd, "badblocks"); - if (pmem->bb_state) - sysfs_put(pmem->bb_state); - else - dev_warn(dev, "sysfs_get_dirent 'badblocks' failed\n"); + if (!pmem->bb_state) + dev_warn(dev, "'badblocks' notification disabled\n"); return 0; } @@ -418,8 +416,18 @@ static int nd_pmem_probe(struct device *dev) static int nd_pmem_remove(struct device *dev) { + struct pmem_device *pmem = dev_get_drvdata(dev); + if (is_nd_btt(dev)) nvdimm_namespace_detach_btt(to_nd_btt(dev)); + else { + /* + * Note, this assumes device_lock() context to not race + * nd_pmem_notify() + */ + sysfs_put(pmem->bb_state); + pmem->bb_state = NULL; + } nvdimm_flush(to_nd_region(dev->parent)); return 0; diff --git a/drivers/nvdimm/region.c b/drivers/nvdimm/region.c index ca94029d20b3..034f0a07d627 100644 --- a/drivers/nvdimm/region.c +++ b/drivers/nvdimm/region.c @@ -60,11 +60,9 @@ static int nd_region_probe(struct device *dev) return -ENODEV; nd_region->bb_state = sysfs_get_dirent(nd_region->dev.kobj.sd, "badblocks"); - if (nd_region->bb_state) - sysfs_put(nd_region->bb_state); - else + if (!nd_region->bb_state) dev_warn(&nd_region->dev, - "sysfs_get_dirent 'badblocks' failed\n"); + "'badblocks' notification disabled\n"); ndr_res.start = nd_region->ndr_start; ndr_res.end = nd_region->ndr_start + nd_region->ndr_size - 1; nvdimm_badblocks_populate(nd_region, &nd_region->bb, &ndr_res); @@ -111,6 +109,13 @@ static int nd_region_remove(struct device *dev) dev_set_drvdata(dev, NULL); nvdimm_bus_unlock(dev); + /* + * Note, this assumes device_lock() context to not race + * nd_region_notify() + */ + sysfs_put(nd_region->bb_state); + nd_region->bb_state = NULL; + return 0; }