device-dax: fix sysfs duplicate warnings

commit bbb3be170ac2891526ad07b18af7db226879a8e7 upstream.

Fix warnings of the form...

     WARNING: CPU: 10 PID: 4983 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80
     sysfs: cannot create duplicate filename '/class/dax/dax12.0'
     Call Trace:
      dump_stack+0x63/0x86
      __warn+0xcb/0xf0
      warn_slowpath_fmt+0x5a/0x80
      ? kernfs_path_from_node+0x4f/0x60
      sysfs_warn_dup+0x62/0x80
      sysfs_do_create_link_sd.isra.2+0x97/0xb0
      sysfs_create_link+0x25/0x40
      device_add+0x266/0x630
      devm_create_dax_dev+0x2cf/0x340 [dax]
      dax_pmem_probe+0x1f5/0x26e [dax_pmem]
      nvdimm_bus_probe+0x71/0x120

...by reusing the namespace id for the device-dax instance name.

Now that we have decided that there will never by more than one
device-dax instance per libnvdimm-namespace parent device [1], we can
directly reuse the namepace ids. There are some possible follow-on
cleanups, but those are saved for a later patch to simplify the -stable
backport.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-December/008266.html

Fixes: 98a29c39dc68 ("libnvdimm, namespace: allow creation of multiple pmem...")
Cc: Jeff Moyer <jmoyer@redhat.com>
Reported-by: Dariusz Dokupil <dariusz.dokupil@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index 586f954..40be374 100644 (file)
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -546,7 +546,8 @@ static void dax_dev_release(struct device *dev)
        struct dax_dev *dax_dev = to_dax_dev(dev);
        struct dax_region *dax_region = dax_dev->region;
 
-       ida_simple_remove(&dax_region->ida, dax_dev->id);
+       if (dax_dev->id >= 0)
+               ida_simple_remove(&dax_region->ida, dax_dev->id);
        ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
        dax_region_put(dax_region);
        iput(dax_dev->inode);
@@ -581,7 +582,7 @@ static void unregister_dax_dev(void *dev)
 }
 
 struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
-               struct resource *res, int count)
+               int id, struct resource *res, int count)
 {
        struct device *parent = dax_region->dev;
        struct dax_dev *dax_dev;
@@ -608,10 +609,16 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
        if (i < count)
                goto err_id;
 
-       dax_dev->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
-       if (dax_dev->id < 0) {
-               rc = dax_dev->id;
-               goto err_id;
+       if (id < 0) {
+               id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
+               dax_dev->id = id;
+               if (id < 0) {
+                       rc = id;
+                       goto err_id;
+               }
+       } else {
+               /* region provider owns @id lifetime */
+               dax_dev->id = -1;
        }
 
        minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL);
@@ -650,7 +657,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
        dev->parent = parent;
        dev->groups = dax_attribute_groups;
        dev->release = dax_dev_release;
-       dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
+       dev_set_name(dev, "dax%d.%d", dax_region->id, id);
        rc = device_add(dev);
        if (rc) {
                kill_dax_dev(dax_dev);
@@ -669,7 +676,8 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
  err_inode:
        ida_simple_remove(&dax_minor_ida, minor);
  err_minor:
-       ida_simple_remove(&dax_region->ida, dax_dev->id);
+       if (dax_dev->id >= 0)
+               ida_simple_remove(&dax_region->ida, dax_dev->id);
  err_id:
        kfree(dax_dev);
 

diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h
index ddd829a..b5ed850 100644 (file)
--- a/drivers/dax/dax.h
+++ b/drivers/dax/dax.h
@@ -21,5 +21,5 @@ struct dax_region *alloc_dax_region(struct device *parent,
                int region_id, struct resource *res, unsigned int align,
                void *addr, unsigned long flags);
 struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
-               struct resource *res, int count);
+               int id, struct resource *res, int count);
 #endif /* __DAX_H__ */

diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 73c6ce9..eebb357 100644 (file)
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -58,13 +58,12 @@ static void dax_pmem_percpu_kill(void *data)
 
 static int dax_pmem_probe(struct device *dev)
 {
-       int rc;
        void *addr;
        struct resource res;
        struct dax_dev *dax_dev;
+       int rc, id, region_id;
        struct nd_pfn_sb *pfn_sb;
        struct dax_pmem *dax_pmem;
-       struct nd_region *nd_region;
        struct nd_namespace_io *nsio;
        struct dax_region *dax_region;
        struct nd_namespace_common *ndns;
@@ -122,14 +121,17 @@ static int dax_pmem_probe(struct device *dev)
        /* adjust the dax_region resource to the start of data */
        res.start += le64_to_cpu(pfn_sb->dataoff);
 
-       nd_region = to_nd_region(dev->parent);
-       dax_region = alloc_dax_region(dev, nd_region->id, &res,
+       rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
+       if (rc != 2)
+               return -EINVAL;
+
+       dax_region = alloc_dax_region(dev, region_id, &res,
                        le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP);
        if (!dax_region)
                return -ENOMEM;
 
        /* TODO: support for subdividing a dax region... */
-       dax_dev = devm_create_dax_dev(dax_region, &res, 1);
+       dax_dev = devm_create_dax_dev(dax_region, id, &res, 1);
 
        /* child dax_dev instances now own the lifetime of the dax_region */
        dax_region_put(dax_region);