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: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
drivers/dax/bus.c | 4 +++-
drivers/dax/super.c | 14 +++++++++-----
drivers/md/dm.c | 2 +-
drivers/nvdimm/pmem.c | 4 ++--
drivers/s390/block/dcssblk.c | 5 +++--
5 files changed, 18 insertions(+), 11 deletions(-)
Index: redhat-linux/drivers/dax/super.c
===================================================================
--- redhat-linux.orig/drivers/dax/super.c 2020-04-01 12:03:39.911439769 -0400
+++ redhat-linux/drivers/dax/super.c 2020-04-01 12:05:31.727439769 -0400
@@ -349,9 +349,6 @@ int dax_zero_page_range(struct dax_devic
{
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 *priva
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 *priva
ida_simple_remove(&dax_minor_ida, minor);
err_minor:
kfree(host);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(alloc_dax);
Index: redhat-linux/drivers/nvdimm/pmem.c
===================================================================
--- redhat-linux.orig/drivers/nvdimm/pmem.c 2020-04-01 12:03:39.911439769 -0400
+++ redhat-linux/drivers/nvdimm/pmem.c 2020-04-01 12:05:31.729439769 -0400
@@ -487,9 +487,9 @@ static int pmem_attach_disk(struct devic
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;
Index: redhat-linux/drivers/dax/bus.c
===================================================================
--- redhat-linux.orig/drivers/dax/bus.c 2020-04-01 12:03:39.911439769 -0400
+++ redhat-linux/drivers/dax/bus.c 2020-04-01 12:05:31.729439769 -0400
@@ -421,8 +421,10 @@ struct dev_dax *__devm_create_dev_dax(st
* 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);
Index: redhat-linux/drivers/s390/block/dcssblk.c
===================================================================
--- redhat-linux.orig/drivers/s390/block/dcssblk.c 2020-04-01 12:03:39.911439769 -0400
+++ redhat-linux/drivers/s390/block/dcssblk.c 2020-04-01 12:05:31.730439769 -0400
@@ -695,8 +695,9 @@ dcssblk_add_store(struct device *dev, st
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;
}
Index: redhat-linux/drivers/md/dm.c
===================================================================
--- redhat-linux.orig/drivers/md/dm.c 2020-04-01 12:03:39.911439769 -0400
+++ redhat-linux/drivers/md/dm.c 2020-04-01 12:05:31.732439769 -0400
@@ -2005,7 +2005,7 @@ static struct mapped_device *alloc_dev(i
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;
}
