Commit 4e4ced93 authored by Vivek Goyal's avatar Vivek Goyal Committed by Dan Williams
Browse files

dax: Move mandatory ->zero_page_range() check in alloc_dax() 



zero_page_range() dax operation is mandatory for dax devices. Right now
that check happens in dax_zero_page_range() function. Dan thinks that's
too late and its better to do the check earlier in alloc_dax().

I also modified alloc_dax() to return pointer with error code in it in
case of failure. Right now it returns NULL and caller assumes failure
happened due to -ENOMEM. But with this ->zero_page_range() check, I
need to return -EINVAL instead.

Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Link: https://lore.kernel.org/r/20200401161125.GB9398@redhat.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 4f3b4f16

drivers/dax/bus.c

+3 −1
Original line number Diff line number Diff line
@@ -421,8 +421,10 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id, 
	 * device outside of mmap of the resulting character device.

	 */

	dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);

	if (!dax_dev)

	if (IS_ERR(dax_dev)) {

		rc = PTR_ERR(dax_dev);

		goto err;

	}



	/* a device_dax instance is dead while the driver is not attached */

	kill_dax(dax_dev);

drivers/dax/super.c

+9 −5
Original line number Diff line number Diff line
@@ -349,9 +349,6 @@ int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 
{

	if (!dax_alive(dax_dev))

		return -ENXIO;



	if (!dax_dev->ops->zero_page_range)

		return -EOPNOTSUPP;

	/*

	 * There are no callers that want to zero more than one page as of now.

	 * Once users are there, this check can be removed after the
@@ -571,9 +568,16 @@ struct dax_device *alloc_dax(void *private, const char *__host, 
	dev_t devt;

	int minor;



	if (ops && !ops->zero_page_range) {

		pr_debug("%s: error: device does not provide dax"

			 " operation zero_page_range()\n",

			 __host ? __host : "Unknown");

		return ERR_PTR(-EINVAL);

	}



	host = kstrdup(__host, GFP_KERNEL);

	if (__host && !host)

		return NULL;

		return ERR_PTR(-ENOMEM);



	minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL);

	if (minor < 0)
@@ -596,7 +600,7 @@ struct dax_device *alloc_dax(void *private, const char *__host, 
	ida_simple_remove(&dax_minor_ida, minor);

 err_minor:

	kfree(host);

	return NULL;

	return ERR_PTR(-ENOMEM);

}

EXPORT_SYMBOL_GPL(alloc_dax);

drivers/md/dm.c

+1 −1
Original line number Diff line number Diff line
@@ -2005,7 +2005,7 @@ static struct mapped_device *alloc_dev(int minor) 
	if (IS_ENABLED(CONFIG_DAX_DRIVER)) {

		md->dax_dev = alloc_dax(md, md->disk->disk_name,

					&dm_dax_ops, 0);

		if (!md->dax_dev)

		if (IS_ERR(md->dax_dev))

			goto bad;

	}

drivers/nvdimm/pmem.c

+2 −2
Original line number Diff line number Diff line
@@ -487,9 +487,9 @@ static int pmem_attach_disk(struct device *dev, 
	if (is_nvdimm_sync(nd_region))

		flags = DAXDEV_F_SYNC;

	dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags);

	if (!dax_dev) {

	if (IS_ERR(dax_dev)) {

		put_disk(disk);

		return -ENOMEM;

		return PTR_ERR(dax_dev);

	}

	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));

	pmem->dax_dev = dax_dev;

drivers/s390/block/dcssblk.c

+3 −2
Original line number Diff line number Diff line
@@ -695,8 +695,9 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char 


	dev_info->dax_dev = alloc_dax(dev_info, dev_info->gd->disk_name,

			&dcssblk_dax_ops, DAXDEV_F_SYNC);

	if (!dev_info->dax_dev) {

		rc = -ENOMEM;

	if (IS_ERR(dev_info->dax_dev)) {

		rc = PTR_ERR(dev_info->dax_dev);

		dev_info->dax_dev = NULL;

		goto put_dev;

	}

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