Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fixes from Dan Williams:
 "A build fix, a NULL de-reference found by static analysis, a misuse of
  the percpu_ref_exit() (tagged for -stable), and notification of failed
  attempts to clear media errors.

  These patches have received a build success notification from the
  0day- kbuild-robot and appeared in next-20161028"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: fix percpu_ref_exit ordering
  nvdimm: make CONFIG_NVDIMM_DAX 'bool'
  pmem: report error on clear poison failure
  libnvdimm, namespace: potential NULL deref on allocation error

5 files changed, 17 insertions, 11 deletions

diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index daadd20aa936..3e2ab3b14eea 100644
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -14,7 +14,7 @@ if DEV_DAX
 
 config DEV_DAX_PMEM
         tristate "PMEM DAX: direct access to persistent memory"
-        depends on NVDIMM_DAX
+        depends on LIBNVDIMM && NVDIMM_DAX
         default DEV_DAX
         help
           Support raw access to persistent memory.  Note that this
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 9630d8837ba9..4a15fa5df98b 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -44,7 +44,6 @@ static void dax_pmem_percpu_exit(void *data)
 
         dev_dbg(dax_pmem->dev, "%s\n", __func__);
         percpu_ref_exit(ref);
-        wait_for_completion(&dax_pmem->cmp);
 }
 
 static void dax_pmem_percpu_kill(void *data)
@@ -54,6 +53,7 @@ static void dax_pmem_percpu_kill(void *data)
 
         dev_dbg(dax_pmem->dev, "%s\n", __func__);
         percpu_ref_kill(ref);
+        wait_for_completion(&dax_pmem->cmp);
 }
 
 static int dax_pmem_probe(struct device *dev)
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 8b2b740d6679..124c2432ac9c 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -89,7 +89,7 @@ config NVDIMM_PFN
           Select Y if unsure
 
 config NVDIMM_DAX
-        tristate "NVDIMM DAX: Raw access to persistent memory"
+        bool "NVDIMM DAX: Raw access to persistent memory"
         default LIBNVDIMM
         depends on NVDIMM_PFN
         help
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 3509cff68ef9..abe5c6bc756c 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -2176,12 +2176,14 @@ static struct device **scan_labels(struct nd_region *nd_region)
         return devs;
 
  err:
-        for (i = 0; devs[i]; i++)
-                if (is_nd_blk(&nd_region->dev))
-                        namespace_blk_release(devs[i]);
-                else
-                        namespace_pmem_release(devs[i]);
-        kfree(devs);
+        if (devs) {
+                for (i = 0; devs[i]; i++)
+                        if (is_nd_blk(&nd_region->dev))
+                                namespace_blk_release(devs[i]);
+                        else
+                                namespace_pmem_release(devs[i]);
+                kfree(devs);
+        }
         return NULL;
 }
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 42b3a8217073..24618431a14b 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -47,7 +47,7 @@ static struct nd_region *to_region(struct pmem_device *pmem)
         return to_nd_region(to_dev(pmem)->parent);
 }
 
-static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
+static int pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
                 unsigned int len)
 {
         struct device *dev = to_dev(pmem);
@@ -62,8 +62,12 @@ static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
                                 __func__, (unsigned long long) sector,
                                 cleared / 512, cleared / 512 > 1 ? "s" : "");
                 badblocks_clear(&pmem->bb, sector, cleared / 512);
+        } else {
+                return -EIO;
         }
+
         invalidate_pmem(pmem->virt_addr + offset, len);
+        return 0;
 }
 
 static void write_pmem(void *pmem_addr, struct page *page,
@@ -123,7 +127,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                 flush_dcache_page(page);
                 write_pmem(pmem_addr, page, off, len);
                 if (unlikely(bad_pmem)) {
-                        pmem_clear_poison(pmem, pmem_off, len);
+                        rc = pmem_clear_poison(pmem, pmem_off, len);
                         write_pmem(pmem_addr, page, off, len);
                 }
         }