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* fix a dax/block device attribute registration regression
@ 2021-09-20  7:27 Christoph Hellwig
  2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
                   ` (2 more replies)
  0 siblings, 3 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-20  7:27 UTC (permalink / raw)
  To: Dan Williams, Jens Axboe
  Cc: Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

Hi Dan and Jens,

this series fixed a regression in how the dax/write_cache attribute of the
pmem devices was registere.  It does so by both fixing the API abuse in the
driver and (temporarily) the behavior change in the block layer that made
this API abuse not work anymore.

Diffstat:
 block/genhd.c         |    3 +-
 drivers/dax/super.c   |   64 --------------------------------------------------
 drivers/nvdimm/pmem.c |   48 ++++++++++++++++++++++++++++++++++---
 include/linux/dax.h   |    2 -
 4 files changed, 46 insertions(+), 71 deletions(-)

^ permalink raw reply	[flat|nested] 16+ messages in thread

* [PATCH 1/3] nvdimm/pmem: fix creating the dax group
  2021-09-20  7:27 fix a dax/block device attribute registration regression Christoph Hellwig
@ 2021-09-20  7:27 ` Christoph Hellwig
  2021-09-20 22:52   ` Ira Weiny
  2021-09-20 23:09   ` Dan Williams
  2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
  2021-09-20  7:27 ` [PATCH 3/3] block: warn if ->groups is set when calling add_disk Christoph Hellwig
  2 siblings, 2 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-20  7:27 UTC (permalink / raw)
  To: Dan Williams, Jens Axboe
  Cc: Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

The recent block layer refactoring broke the way how the pmem driver
abused device_add_disk.  Fix this by properly passing the attribute groups
to device_add_disk.

Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvdimm/pmem.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 72de88ff0d30d..ef4950f808326 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -380,7 +380,6 @@ static int pmem_attach_disk(struct device *dev,
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
 	struct request_queue *q;
-	struct device *gendev;
 	struct gendisk *disk;
 	void *addr;
 	int rc;
@@ -489,10 +488,8 @@ static int pmem_attach_disk(struct device *dev,
 	}
 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
 	pmem->dax_dev = dax_dev;
-	gendev = disk_to_dev(disk);
-	gendev->groups = pmem_attribute_groups;
 
-	device_add_disk(dev, disk, NULL);
+	device_add_disk(dev, disk, pmem_attribute_groups);
 	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
 		return -ENOMEM;
 
-- 
2.30.2


^ permalink raw reply	[flat|nested] 16+ messages in thread

* [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20  7:27 fix a dax/block device attribute registration regression Christoph Hellwig
  2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
@ 2021-09-20  7:27 ` Christoph Hellwig
  2021-09-20 18:00   ` kernel test robot
                     ` (2 more replies)
  2021-09-20  7:27 ` [PATCH 3/3] block: warn if ->groups is set when calling add_disk Christoph Hellwig
  2 siblings, 3 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-20  7:27 UTC (permalink / raw)
  To: Dan Williams, Jens Axboe
  Cc: Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

dax_attribute_group is only used by the pmem driver, and can avoid the
completely pointless lookup by the disk name if moved there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/dax/super.c   | 64 -------------------------------------------
 drivers/nvdimm/pmem.c | 43 +++++++++++++++++++++++++++++
 include/linux/dax.h   |  2 --
 3 files changed, 43 insertions(+), 66 deletions(-)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index fc89e91beea7c..e03d94bdc0449 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -231,70 +231,6 @@ enum dax_device_flags {
 	DAXDEV_SYNC,
 };
 
-static ssize_t write_cache_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
-	ssize_t rc;
-
-	WARN_ON_ONCE(!dax_dev);
-	if (!dax_dev)
-		return -ENXIO;
-
-	rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev));
-	put_dax(dax_dev);
-	return rc;
-}
-
-static ssize_t write_cache_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
-{
-	bool write_cache;
-	int rc = strtobool(buf, &write_cache);
-	struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
-
-	WARN_ON_ONCE(!dax_dev);
-	if (!dax_dev)
-		return -ENXIO;
-
-	if (rc)
-		len = rc;
-	else
-		dax_write_cache(dax_dev, write_cache);
-
-	put_dax(dax_dev);
-	return len;
-}
-static DEVICE_ATTR_RW(write_cache);
-
-static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
-{
-	struct device *dev = container_of(kobj, typeof(*dev), kobj);
-	struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
-
-	WARN_ON_ONCE(!dax_dev);
-	if (!dax_dev)
-		return 0;
-
-#ifndef CONFIG_ARCH_HAS_PMEM_API
-	if (a == &dev_attr_write_cache.attr)
-		return 0;
-#endif
-	return a->mode;
-}
-
-static struct attribute *dax_attributes[] = {
-	&dev_attr_write_cache.attr,
-	NULL,
-};
-
-struct attribute_group dax_attribute_group = {
-	.name = "dax",
-	.attrs = dax_attributes,
-	.is_visible = dax_visible,
-};
-EXPORT_SYMBOL_GPL(dax_attribute_group);
-
 /**
  * dax_direct_access() - translate a device pgoff to an absolute pfn
  * @dax_dev: a dax_device instance representing the logical memory range
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index ef4950f808326..bbeb3f46db157 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -328,6 +328,49 @@ static const struct dax_operations pmem_dax_ops = {
 	.zero_page_range = pmem_dax_zero_page_range,
 };
 
+static ssize_t write_cache_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
+
+	return sprintf(buf, "%d\n", !!dax_write_cache_enabled(pmem->dax_dev));
+}
+
+static ssize_t write_cache_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
+	bool write_cache;
+	int rc;
+
+	rc = strtobool(buf, &write_cache);
+	if (rc)
+		return rc;
+	dax_write_cache(pmem->dax_dev, write_cache);
+	return len;
+}
+static DEVICE_ATTR_RW(write_cache);
+
+static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+#ifndef CONFIG_ARCH_HAS_PMEM_API
+	if (a == &dev_attr_write_cache.attr)
+		return 0;
+#endif
+	return a->mode;
+}
+
+static struct attribute *dax_attributes[] = {
+	&dev_attr_write_cache.attr,
+	NULL,
+};
+
+static const struct attribute_group dax_attribute_group = {
+	.name		= "dax",
+	.attrs		= dax_attributes,
+	.is_visible	= dax_visible,
+};
+
 static const struct attribute_group *pmem_attribute_groups[] = {
 	&dax_attribute_group,
 	NULL,
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 2619d94c308d4..8623caa673889 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -38,8 +38,6 @@ struct dax_operations {
 	int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
 };
 
-extern struct attribute_group dax_attribute_group;
-
 #if IS_ENABLED(CONFIG_DAX)
 struct dax_device *alloc_dax(void *private, const char *host,
 		const struct dax_operations *ops, unsigned long flags);
-- 
2.30.2


^ permalink raw reply	[flat|nested] 16+ messages in thread

* [PATCH 3/3] block: warn if ->groups is set when calling add_disk
  2021-09-20  7:27 fix a dax/block device attribute registration regression Christoph Hellwig
  2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
  2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
@ 2021-09-20  7:27 ` Christoph Hellwig
  2021-09-20 22:52   ` Ira Weiny
  2021-09-20 23:50   ` Dan Williams
  2 siblings, 2 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-20  7:27 UTC (permalink / raw)
  To: Dan Williams, Jens Axboe
  Cc: Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

The proper API is to pass the groups to device_add_disk, but the code
used to also allow groups being set before calling *add_disk.  Warn
about that but keep the group pointer intact for now so that it can
be removed again after a grace period.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
---
 block/genhd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 7b6e5e1cf9564..409cf608cc5bd 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -439,7 +439,8 @@ int device_add_disk(struct device *parent, struct gendisk *disk,
 	dev_set_uevent_suppress(ddev, 1);
 
 	ddev->parent = parent;
-	ddev->groups = groups;
+	if (!WARN_ON_ONCE(ddev->groups))
+		ddev->groups = groups;
 	dev_set_name(ddev, "%s", disk->disk_name);
 	if (!(disk->flags & GENHD_FL_HIDDEN))
 		ddev->devt = MKDEV(disk->major, disk->first_minor);
-- 
2.30.2


^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
@ 2021-09-20 18:00   ` kernel test robot
  2021-09-20 23:29     ` Dan Williams
  2021-09-20 22:51   ` Ira Weiny
  2021-09-20 23:37   ` Dan Williams
  2 siblings, 1 reply; 16+ messages in thread
From: kernel test robot @ 2021-09-20 18:00 UTC (permalink / raw)
  To: Christoph Hellwig, Dan Williams, Jens Axboe
  Cc: kbuild-all, Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

[-- Attachment #1: Type: text/plain, Size: 4375 bytes --]

Hi Christoph,

I love your patch! Yet something to improve:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linus/master v5.15-rc2 next-20210920]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Christoph-Hellwig/nvdimm-pmem-fix-creating-the-dax-group/20210920-162804
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: riscv-buildonly-randconfig-r006-20210920 (attached as .config)
compiler: riscv64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/1a16d0f32f70bcd159a9f8cf32794f4024e8711e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christoph-Hellwig/nvdimm-pmem-fix-creating-the-dax-group/20210920-162804
        git checkout 1a16d0f32f70bcd159a9f8cf32794f4024e8711e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/dax/super.c:375:6: error: no previous prototype for 'run_dax' [-Werror=missing-prototypes]
     375 | void run_dax(struct dax_device *dax_dev)
         |      ^~~~~~~
>> drivers/dax/super.c:70:27: error: 'dax_get_by_host' defined but not used [-Werror=unused-function]
      70 | static struct dax_device *dax_get_by_host(const char *host)
         |                           ^~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors


vim +/dax_get_by_host +70 drivers/dax/super.c

1b7646014e0d838b Christoph Hellwig 2021-08-26  65  
1b7646014e0d838b Christoph Hellwig 2021-08-26  66  /**
1b7646014e0d838b Christoph Hellwig 2021-08-26  67   * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
1b7646014e0d838b Christoph Hellwig 2021-08-26  68   * @host: alternate name for the device registered by a dax driver
1b7646014e0d838b Christoph Hellwig 2021-08-26  69   */
1b7646014e0d838b Christoph Hellwig 2021-08-26 @70  static struct dax_device *dax_get_by_host(const char *host)
1b7646014e0d838b Christoph Hellwig 2021-08-26  71  {
1b7646014e0d838b Christoph Hellwig 2021-08-26  72  	struct dax_device *dax_dev, *found = NULL;
1b7646014e0d838b Christoph Hellwig 2021-08-26  73  	int hash, id;
1b7646014e0d838b Christoph Hellwig 2021-08-26  74  
1b7646014e0d838b Christoph Hellwig 2021-08-26  75  	if (!host)
1b7646014e0d838b Christoph Hellwig 2021-08-26  76  		return NULL;
1b7646014e0d838b Christoph Hellwig 2021-08-26  77  
1b7646014e0d838b Christoph Hellwig 2021-08-26  78  	hash = dax_host_hash(host);
1b7646014e0d838b Christoph Hellwig 2021-08-26  79  
1b7646014e0d838b Christoph Hellwig 2021-08-26  80  	id = dax_read_lock();
1b7646014e0d838b Christoph Hellwig 2021-08-26  81  	spin_lock(&dax_host_lock);
1b7646014e0d838b Christoph Hellwig 2021-08-26  82  	hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
1b7646014e0d838b Christoph Hellwig 2021-08-26  83  		if (!dax_alive(dax_dev)
1b7646014e0d838b Christoph Hellwig 2021-08-26  84  				|| strcmp(host, dax_dev->host) != 0)
1b7646014e0d838b Christoph Hellwig 2021-08-26  85  			continue;
1b7646014e0d838b Christoph Hellwig 2021-08-26  86  
1b7646014e0d838b Christoph Hellwig 2021-08-26  87  		if (igrab(&dax_dev->inode))
1b7646014e0d838b Christoph Hellwig 2021-08-26  88  			found = dax_dev;
1b7646014e0d838b Christoph Hellwig 2021-08-26  89  		break;
1b7646014e0d838b Christoph Hellwig 2021-08-26  90  	}
1b7646014e0d838b Christoph Hellwig 2021-08-26  91  	spin_unlock(&dax_host_lock);
1b7646014e0d838b Christoph Hellwig 2021-08-26  92  	dax_read_unlock(id);
1b7646014e0d838b Christoph Hellwig 2021-08-26  93  
1b7646014e0d838b Christoph Hellwig 2021-08-26  94  	return found;
1b7646014e0d838b Christoph Hellwig 2021-08-26  95  }
1b7646014e0d838b Christoph Hellwig 2021-08-26  96  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 28763 bytes --]

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
  2021-09-20 18:00   ` kernel test robot
@ 2021-09-20 22:51   ` Ira Weiny
  2021-09-20 23:36     ` Dan Williams
  2021-09-20 23:37   ` Dan Williams
  2 siblings, 1 reply; 16+ messages in thread
From: Ira Weiny @ 2021-09-20 22:51 UTC (permalink / raw)
  To: Christoph Hellwig, Dan Williams
  Cc: Dan Williams, Jens Axboe, Vishal Verma, Dave Jiang, linux-block, nvdimm

On Mon, Sep 20, 2021 at 09:27:25AM +0200, Christoph Hellwig wrote:

...

> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index ef4950f808326..bbeb3f46db157 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -328,6 +328,49 @@ static const struct dax_operations pmem_dax_ops = {
>  	.zero_page_range = pmem_dax_zero_page_range,
>  };
>  
> +static ssize_t write_cache_show(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +	struct pmem_device *pmem = dev_to_disk(dev)->private_data;

I want to say this should be dax_get_private()...  However, looking at the use
of dax_get_private() not a single caller checks for NULL!  :-(

So now I wonder why dax_get_private() exists...  :-/

A quick history search does not make anything apparent.  When the DAXDEV_ALIVE
check was added to dax_get_private() no callers were changed to account for a
potential NULL return.

Dan?

> +
> +	return sprintf(buf, "%d\n", !!dax_write_cache_enabled(pmem->dax_dev));
> +}
> +
> +static ssize_t write_cache_store(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t len)
> +{
> +	struct pmem_device *pmem = dev_to_disk(dev)->private_data;

Same here...

Ira


^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 1/3] nvdimm/pmem: fix creating the dax group
  2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
@ 2021-09-20 22:52   ` Ira Weiny
  2021-09-20 23:09   ` Dan Williams
  1 sibling, 0 replies; 16+ messages in thread
From: Ira Weiny @ 2021-09-20 22:52 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Dan Williams, Jens Axboe, Vishal Verma, Dave Jiang, linux-block, nvdimm

On Mon, Sep 20, 2021 at 09:27:24AM +0200, Christoph Hellwig wrote:
> The recent block layer refactoring broke the way how the pmem driver
> abused device_add_disk.  Fix this by properly passing the attribute groups
> to device_add_disk.
> 
> Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> ---
>  drivers/nvdimm/pmem.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 72de88ff0d30d..ef4950f808326 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -380,7 +380,6 @@ static int pmem_attach_disk(struct device *dev,
>  	struct nd_pfn_sb *pfn_sb;
>  	struct pmem_device *pmem;
>  	struct request_queue *q;
> -	struct device *gendev;
>  	struct gendisk *disk;
>  	void *addr;
>  	int rc;
> @@ -489,10 +488,8 @@ static int pmem_attach_disk(struct device *dev,
>  	}
>  	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
>  	pmem->dax_dev = dax_dev;
> -	gendev = disk_to_dev(disk);
> -	gendev->groups = pmem_attribute_groups;
>  
> -	device_add_disk(dev, disk, NULL);
> +	device_add_disk(dev, disk, pmem_attribute_groups);
>  	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
>  		return -ENOMEM;
>  
> -- 
> 2.30.2
> 

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 3/3] block: warn if ->groups is set when calling add_disk
  2021-09-20  7:27 ` [PATCH 3/3] block: warn if ->groups is set when calling add_disk Christoph Hellwig
@ 2021-09-20 22:52   ` Ira Weiny
  2021-09-20 23:50   ` Dan Williams
  1 sibling, 0 replies; 16+ messages in thread
From: Ira Weiny @ 2021-09-20 22:52 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Dan Williams, Jens Axboe, Vishal Verma, Dave Jiang, linux-block, nvdimm

On Mon, Sep 20, 2021 at 09:27:26AM +0200, Christoph Hellwig wrote:
> The proper API is to pass the groups to device_add_disk, but the code
> used to also allow groups being set before calling *add_disk.  Warn
> about that but keep the group pointer intact for now so that it can
> be removed again after a grace period.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> ---
>  block/genhd.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 7b6e5e1cf9564..409cf608cc5bd 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -439,7 +439,8 @@ int device_add_disk(struct device *parent, struct gendisk *disk,
>  	dev_set_uevent_suppress(ddev, 1);
>  
>  	ddev->parent = parent;
> -	ddev->groups = groups;
> +	if (!WARN_ON_ONCE(ddev->groups))
> +		ddev->groups = groups;
>  	dev_set_name(ddev, "%s", disk->disk_name);
>  	if (!(disk->flags & GENHD_FL_HIDDEN))
>  		ddev->devt = MKDEV(disk->major, disk->first_minor);
> -- 
> 2.30.2
> 

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 1/3] nvdimm/pmem: fix creating the dax group
  2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
  2021-09-20 22:52   ` Ira Weiny
@ 2021-09-20 23:09   ` Dan Williams
  1 sibling, 0 replies; 16+ messages in thread
From: Dan Williams @ 2021-09-20 23:09 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Vishal Verma, Dave Jiang, Ira Weiny, linux-block,
	Linux NVDIMM

On Mon, Sep 20, 2021 at 12:29 AM Christoph Hellwig <hch@lst.de> wrote:
>
> The recent block layer refactoring broke the way how the pmem driver
> abused device_add_disk.  Fix this by properly passing the attribute groups
> to device_add_disk.
>
> Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")

This also fixes the the way the pmem driver abused device_add_disk(),
so perhaps add:

Fixes: fef912bf860e ("block: genhd: add 'groups' argument to device_add_disk")

...as well. It's not a stable fix as this is only a cosmetic fixup
until the most recent refactoring turned it into a bug.

Either way, you can add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20 18:00   ` kernel test robot
@ 2021-09-20 23:29     ` Dan Williams
  0 siblings, 0 replies; 16+ messages in thread
From: Dan Williams @ 2021-09-20 23:29 UTC (permalink / raw)
  To: kernel test robot
  Cc: Christoph Hellwig, Jens Axboe, kbuild-all, Vishal Verma,
	Dave Jiang, Ira Weiny, linux-block, Linux NVDIMM

On Mon, Sep 20, 2021 at 11:01 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Christoph,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on axboe-block/for-next]
> [also build test ERROR on linus/master v5.15-rc2 next-20210920]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:    https://github.com/0day-ci/linux/commits/Christoph-Hellwig/nvdimm-pmem-fix-creating-the-dax-group/20210920-162804
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
> config: riscv-buildonly-randconfig-r006-20210920 (attached as .config)
> compiler: riscv64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/0day-ci/linux/commit/1a16d0f32f70bcd159a9f8cf32794f4024e8711e
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Christoph-Hellwig/nvdimm-pmem-fix-creating-the-dax-group/20210920-162804
>         git checkout 1a16d0f32f70bcd159a9f8cf32794f4024e8711e
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=riscv
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>    drivers/dax/super.c:375:6: error: no previous prototype for 'run_dax' [-Werror=missing-prototypes]
>      375 | void run_dax(struct dax_device *dax_dev)
>          |      ^~~~~~~

In this new -Werror world drivers/dax/bus.c needs:

#include "bus.h"

> >> drivers/dax/super.c:70:27: error: 'dax_get_by_host' defined but not used [-Werror=unused-function]
>       70 | static struct dax_device *dax_get_by_host(const char *host)
>          |                           ^~~~~~~~~~~~~~~
>    cc1: all warnings being treated as errors

Nice additional cleanup that now fs_dax_get_by_bdev() is the only
caller of dax_get_by_host().

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20 22:51   ` Ira Weiny
@ 2021-09-20 23:36     ` Dan Williams
  0 siblings, 0 replies; 16+ messages in thread
From: Dan Williams @ 2021-09-20 23:36 UTC (permalink / raw)
  To: Ira Weiny
  Cc: Christoph Hellwig, Jens Axboe, Vishal Verma, Dave Jiang,
	linux-block, Linux NVDIMM

On Mon, Sep 20, 2021 at 3:51 PM Ira Weiny <ira.weiny@intel.com> wrote:
>
> On Mon, Sep 20, 2021 at 09:27:25AM +0200, Christoph Hellwig wrote:
>
> ...
>
> > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> > index ef4950f808326..bbeb3f46db157 100644
> > --- a/drivers/nvdimm/pmem.c
> > +++ b/drivers/nvdimm/pmem.c
> > @@ -328,6 +328,49 @@ static const struct dax_operations pmem_dax_ops = {
> >       .zero_page_range = pmem_dax_zero_page_range,
> >  };
> >
> > +static ssize_t write_cache_show(struct device *dev,
> > +             struct device_attribute *attr, char *buf)
> > +{
> > +     struct pmem_device *pmem = dev_to_disk(dev)->private_data;
>
> I want to say this should be dax_get_private()...  However, looking at the use

No, this wants to do from @dev to @dax_dev. dax_get_private() assumes
that @dax_dev is already known. Also, in this case @dev is the gendisk
device, so this is a gendisk-to-dax-device with special knowledge that
the gendisk is for a pmem device.

> of dax_get_private() not a single caller checks for NULL!  :-(

All the callers are correctly assuming that their usage is before kill_dax().

>
> So now I wonder why dax_get_private() exists...  :-/

It exists so that the definition of 'struct dax_device' can remain
private, as no one should be directly mucking with dax_device
internals outside of the provided APIs.

> A quick history search does not make anything apparent.  When the DAXDEV_ALIVE
> check was added to dax_get_private() no callers were changed to account for a
> potential NULL return.
>
> Dan?

I double checked, but this all looks ok to me.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem
  2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
  2021-09-20 18:00   ` kernel test robot
  2021-09-20 22:51   ` Ira Weiny
@ 2021-09-20 23:37   ` Dan Williams
  2 siblings, 0 replies; 16+ messages in thread
From: Dan Williams @ 2021-09-20 23:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Vishal Verma, Dave Jiang, Ira Weiny, linux-block,
	Linux NVDIMM

On Mon, Sep 20, 2021 at 12:29 AM Christoph Hellwig <hch@lst.de> wrote:
>
> dax_attribute_group is only used by the pmem driver, and can avoid the
> completely pointless lookup by the disk name if moved there.

After the additional fixups that 0day-robot found, you can add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 3/3] block: warn if ->groups is set when calling add_disk
  2021-09-20  7:27 ` [PATCH 3/3] block: warn if ->groups is set when calling add_disk Christoph Hellwig
  2021-09-20 22:52   ` Ira Weiny
@ 2021-09-20 23:50   ` Dan Williams
  2021-09-21  6:32     ` Christoph Hellwig
  1 sibling, 1 reply; 16+ messages in thread
From: Dan Williams @ 2021-09-20 23:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Vishal Verma, Dave Jiang, Ira Weiny, linux-block,
	Linux NVDIMM

On Mon, Sep 20, 2021 at 12:30 AM Christoph Hellwig <hch@lst.de> wrote:
>
> The proper API is to pass the groups to device_add_disk, but the code
> used to also allow groups being set before calling *add_disk.  Warn
> about that but keep the group pointer intact for now so that it can
> be removed again after a grace period.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
> ---
>  block/genhd.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 7b6e5e1cf9564..409cf608cc5bd 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -439,7 +439,8 @@ int device_add_disk(struct device *parent, struct gendisk *disk,
>         dev_set_uevent_suppress(ddev, 1);
>
>         ddev->parent = parent;
> -       ddev->groups = groups;
> +       if (!WARN_ON_ONCE(ddev->groups))
> +               ddev->groups = groups;

That feels too compact to me, and dev_WARN_ONCE() might save someone a
git blame to look up the reason for the warning:

    dev_WARN_ONCE(parent, ddev->groups, "unexpected pre-populated
attribute group\n");
    if (!ddev->groups)
        ddev->groups = groups;

...but not a deal breaker. Either way you can add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

Jens, I'm ok for the final spin of this series to go through block.git
since the referenced commits in Fixes: went that route, just let me
know if you want me to take them.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: [PATCH 3/3] block: warn if ->groups is set when calling add_disk
  2021-09-20 23:50   ` Dan Williams
@ 2021-09-21  6:32     ` Christoph Hellwig
  0 siblings, 0 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-21  6:32 UTC (permalink / raw)
  To: Dan Williams
  Cc: Christoph Hellwig, Jens Axboe, Vishal Verma, Dave Jiang,
	Ira Weiny, linux-block, Linux NVDIMM

On Mon, Sep 20, 2021 at 04:50:03PM -0700, Dan Williams wrote:
> >
> >         ddev->parent = parent;
> > -       ddev->groups = groups;
> > +       if (!WARN_ON_ONCE(ddev->groups))
> > +               ddev->groups = groups;
> 
> That feels too compact to me, and dev_WARN_ONCE() might save someone a
> git blame to look up the reason for the warning:
> 
>     dev_WARN_ONCE(parent, ddev->groups, "unexpected pre-populated
> attribute group\n");
>     if (!ddev->groups)
>         ddev->groups = groups;
> 
> ...but not a deal breaker. Either way you can add:
> 

I'd rather keep it simple and optmize for the normal case..

^ permalink raw reply	[flat|nested] 16+ messages in thread

* [PATCH 1/3] nvdimm/pmem: fix creating the dax group
  2021-09-22 18:33 fix a dax/block device attribute registration regression Christoph Hellwig
@ 2021-09-22 18:33 ` Christoph Hellwig
  0 siblings, 0 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-22 18:33 UTC (permalink / raw)
  To: Dan Williams, Jens Axboe
  Cc: Vishal Verma, Dave Jiang, Ira Weiny, linux-block, nvdimm

The recent block layer refactoring broke the way how the pmem driver
abused device_add_disk.  Fix this by properly passing the attribute groups
to device_add_disk.

Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pmem.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 72de88ff0d30d..ef4950f808326 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -380,7 +380,6 @@ static int pmem_attach_disk(struct device *dev,
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
 	struct request_queue *q;
-	struct device *gendev;
 	struct gendisk *disk;
 	void *addr;
 	int rc;
@@ -489,10 +488,8 @@ static int pmem_attach_disk(struct device *dev,
 	}
 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
 	pmem->dax_dev = dax_dev;
-	gendev = disk_to_dev(disk);
-	gendev->groups = pmem_attribute_groups;
 
-	device_add_disk(dev, disk, NULL);
+	device_add_disk(dev, disk, pmem_attribute_groups);
 	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
 		return -ENOMEM;
 
-- 
2.30.2


^ permalink raw reply	[flat|nested] 16+ messages in thread

* [PATCH 1/3] nvdimm/pmem: fix creating the dax group
  2021-09-22 17:34 dax_supported() related cleanups v2 Christoph Hellwig
@ 2021-09-22 17:34 ` Christoph Hellwig
  0 siblings, 0 replies; 16+ messages in thread
From: Christoph Hellwig @ 2021-09-22 17:34 UTC (permalink / raw)
  To: Dan Williams, Vishal Verma, Dave Jiang
  Cc: Mike Snitzer, Matthew Wilcox, linux-xfs, nvdimm, linux-fsdevel,
	linux-ext4, Ira Weiny

The recent block layer refactoring broke the way how the pmem driver
abused device_add_disk.  Fix this by properly passing the attribute groups
to device_add_disk.

Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pmem.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 72de88ff0d30d..ef4950f808326 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -380,7 +380,6 @@ static int pmem_attach_disk(struct device *dev,
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
 	struct request_queue *q;
-	struct device *gendev;
 	struct gendisk *disk;
 	void *addr;
 	int rc;
@@ -489,10 +488,8 @@ static int pmem_attach_disk(struct device *dev,
 	}
 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
 	pmem->dax_dev = dax_dev;
-	gendev = disk_to_dev(disk);
-	gendev->groups = pmem_attribute_groups;
 
-	device_add_disk(dev, disk, NULL);
+	device_add_disk(dev, disk, pmem_attribute_groups);
 	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
 		return -ENOMEM;
 
-- 
2.30.2


^ permalink raw reply	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2021-09-22 18:35 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-20  7:27 fix a dax/block device attribute registration regression Christoph Hellwig
2021-09-20  7:27 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
2021-09-20 22:52   ` Ira Weiny
2021-09-20 23:09   ` Dan Williams
2021-09-20  7:27 ` [PATCH 2/3] nvdimm/pmem: move dax_attribute_group from dax to pmem Christoph Hellwig
2021-09-20 18:00   ` kernel test robot
2021-09-20 23:29     ` Dan Williams
2021-09-20 22:51   ` Ira Weiny
2021-09-20 23:36     ` Dan Williams
2021-09-20 23:37   ` Dan Williams
2021-09-20  7:27 ` [PATCH 3/3] block: warn if ->groups is set when calling add_disk Christoph Hellwig
2021-09-20 22:52   ` Ira Weiny
2021-09-20 23:50   ` Dan Williams
2021-09-21  6:32     ` Christoph Hellwig
2021-09-22 17:34 dax_supported() related cleanups v2 Christoph Hellwig
2021-09-22 17:34 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig
2021-09-22 18:33 fix a dax/block device attribute registration regression Christoph Hellwig
2021-09-22 18:33 ` [PATCH 1/3] nvdimm/pmem: fix creating the dax group Christoph Hellwig

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