From 6aa734a2f38e2e17ac4de3561770b8676b27af2e Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 30 Jun 2017 18:56:03 -0700 Subject: [PATCH] libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime 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; } -- 2.20.1