In preparation for checking whether the architecture has data cache
aliasing within alloc_dax(), modify the error handling of nvdimm/pmem
pmem_attach_disk() to treat alloc_dax() -EOPNOTSUPP failure as non-fatal.
For the transition, consider that alloc_dax() returning NULL is the
same as returning -EOPNOTSUPP.
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: Mikulas Patocka <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Russell King <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
drivers/nvdimm/pmem.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 9fe358090720..f1d9f5c6dbac 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -558,19 +558,21 @@ static int pmem_attach_disk(struct device *dev,
disk->bb = &pmem->bb;
dax_dev = alloc_dax(pmem, &pmem_dax_ops);
- if (IS_ERR(dax_dev)) {
- rc = PTR_ERR(dax_dev);
- goto out;
+ if (IS_ERR_OR_NULL(dax_dev)) {
+ rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP;
+ if (rc != -EOPNOTSUPP)
+ goto out;
+ } else {
+ set_dax_nocache(dax_dev);
+ set_dax_nomc(dax_dev);
+ if (is_nvdimm_sync(nd_region))
+ set_dax_synchronous(dax_dev);
+ pmem->dax_dev = dax_dev;
+ rc = dax_add_host(dax_dev, disk);
+ if (rc)
+ goto out_cleanup_dax;
+ dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
}
- set_dax_nocache(dax_dev);
- set_dax_nomc(dax_dev);
- if (is_nvdimm_sync(nd_region))
- set_dax_synchronous(dax_dev);
- pmem->dax_dev = dax_dev;
- rc = dax_add_host(dax_dev, disk);
- if (rc)
- goto out_cleanup_dax;
- dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
rc = device_add_disk(dev, disk, pmem_attribute_groups);
if (rc)
goto out_remove_host;
--
2.39.2
Mathieu Desnoyers wrote:
> In preparation for checking whether the architecture has data cache
> aliasing within alloc_dax(), modify the error handling of nvdimm/pmem
> pmem_attach_disk() to treat alloc_dax() -EOPNOTSUPP failure as non-fatal.
>
> For the transition, consider that alloc_dax() returning NULL is the
> same as returning -EOPNOTSUPP.
>
> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Alasdair Kergon <[email protected]>
> Cc: Mike Snitzer <[email protected]>
> Cc: Mikulas Patocka <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: Matthew Wilcox <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Russell King <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> drivers/nvdimm/pmem.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 9fe358090720..f1d9f5c6dbac 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -558,19 +558,21 @@ static int pmem_attach_disk(struct device *dev,
> disk->bb = &pmem->bb;
>
> dax_dev = alloc_dax(pmem, &pmem_dax_ops);
> - if (IS_ERR(dax_dev)) {
> - rc = PTR_ERR(dax_dev);
> - goto out;
> + if (IS_ERR_OR_NULL(dax_dev)) {
alloc_dax() should never return NULL. I.e. the lead in before this patch
should fix this misunderstanding:
diff --git a/include/linux/dax.h b/include/linux/dax.h
index b463502b16e1..df2d52b8a245 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -86,11 +86,7 @@ static inline void *dax_holder(struct dax_device *dax_dev)
static inline struct dax_device *alloc_dax(void *private,
const struct dax_operations *ops)
{
- /*
- * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
- * NULL is an error or expected.
- */
- return NULL;
+ return ERR_PTR(-EOPNOTSUPP);
}
static inline void put_dax(struct dax_device *dax_dev)
{
> + rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP;
Then this ternary can be replaced with just a check of which PTR_ERR()
value is being returned.
On 2024-02-08 16:32, Dan Williams wrote:
> Mathieu Desnoyers wrote:
>> In preparation for checking whether the architecture has data cache
>> aliasing within alloc_dax(), modify the error handling of nvdimm/pmem
>> pmem_attach_disk() to treat alloc_dax() -EOPNOTSUPP failure as non-fatal.
>>
>> For the transition, consider that alloc_dax() returning NULL is the
>> same as returning -EOPNOTSUPP.
>>
>> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
>> Signed-off-by: Mathieu Desnoyers <[email protected]>
>> Cc: Alasdair Kergon <[email protected]>
>> Cc: Mike Snitzer <[email protected]>
>> Cc: Mikulas Patocka <[email protected]>
>> Cc: Andrew Morton <[email protected]>
>> Cc: Linus Torvalds <[email protected]>
>> Cc: Dan Williams <[email protected]>
>> Cc: Vishal Verma <[email protected]>
>> Cc: Dave Jiang <[email protected]>
>> Cc: Matthew Wilcox <[email protected]>
>> Cc: Arnd Bergmann <[email protected]>
>> Cc: Russell King <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> ---
>> drivers/nvdimm/pmem.c | 26 ++++++++++++++------------
>> 1 file changed, 14 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
>> index 9fe358090720..f1d9f5c6dbac 100644
>> --- a/drivers/nvdimm/pmem.c
>> +++ b/drivers/nvdimm/pmem.c
>> @@ -558,19 +558,21 @@ static int pmem_attach_disk(struct device *dev,
>> disk->bb = &pmem->bb;
>>
>> dax_dev = alloc_dax(pmem, &pmem_dax_ops);
>> - if (IS_ERR(dax_dev)) {
>> - rc = PTR_ERR(dax_dev);
>> - goto out;
>> + if (IS_ERR_OR_NULL(dax_dev)) {
>
> alloc_dax() should never return NULL. I.e. the lead in before this patch
> should fix this misunderstanding:
>
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index b463502b16e1..df2d52b8a245 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -86,11 +86,7 @@ static inline void *dax_holder(struct dax_device *dax_dev)
> static inline struct dax_device *alloc_dax(void *private,
> const struct dax_operations *ops)
> {
> - /*
> - * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
> - * NULL is an error or expected.
> - */
> - return NULL;
> + return ERR_PTR(-EOPNOTSUPP);
> }
> static inline void put_dax(struct dax_device *dax_dev)
> {
>
>> + rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP;
>
> Then this ternary can be replaced with just a check of which PTR_ERR()
> value is being returned.
As you noted, I've introduced this as cleanups in later patches. I don't
mind folding these into their respective per-driver commits and moving
the alloc_dax() hunk earlier in the series.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com