RE: [PATCH v4 08/12] dax: Fix incorrect list of data cache aliasing architectures
Mathieu Desnoyers wrote:
> commit d92576f1167c ("dax: does not work correctly with virtual aliasing
> caches")
> prevents DAX from building on architectures with virtually aliased
> dcache with:
>
> depends on !(ARM || MIPS || SPARC)
>
> This check is too broad (e.g. recent ARMv7 don't have virtually aliased
> dcaches), and also misses many other architectures with virtually
> aliased data cache.
>
> This is a regression introduced in the v4.0 Linux kernel where the
> dax mount option is removed for 32-bit ARMv7 boards which have no data
> cache aliasing, and therefore should work fine with FS_DAX.
>
> This was turned into the following check in alloc_dax() by a preparatory
> change:
>
> if (ops && (IS_ENABLED(CONFIG_ARM) ||
> IS_ENABLED(CONFIG_MIPS) ||
> IS_ENABLED(CONFIG_SPARC)))
> return NULL;
>
> Use cpu_dcache_is_aliasing() instead to figure out whether the environment
> has aliasing data caches.
>
> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing
> caches")
> Signed-off-by: Mathieu Desnoyers
> Cc: Andrew Morton
> Cc: Linus Torvalds
> Cc: Dan Williams
> Cc: Vishal Verma
> Cc: Dave Jiang
> Cc: Matthew Wilcox
> Cc: Arnd Bergmann
> Cc: Russell King
> Cc: linux-a...@vger.kernel.org
> Cc: linux-...@vger.kernel.org
> Cc: linux-fsde...@vger.kernel.org
> Cc: linux...@kvack.org
> Cc: linux-...@vger.kernel.org
> Cc: dm-devel@lists.linux.dev
> Cc: nvd...@lists.linux.dev
> ---
> drivers/dax/super.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index ce5bffa86bba..a21a7c262382 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -13,6 +13,7 @@
> #include
> #include
> #include
> +#include
> #include "dax-private.h"
>
> /**
> @@ -455,9 +456,7 @@ struct dax_device *alloc_dax(void *private, const struct
> dax_operations *ops)
>* except for device-dax (NULL operations pointer), which does
>* not use aliased mappings from the kernel.
>*/
> - if (ops && (IS_ENABLED(CONFIG_ARM) ||
> - IS_ENABLED(CONFIG_MIPS) ||
> - IS_ENABLED(CONFIG_SPARC)))
> + if (ops && cpu_dcache_is_aliasing())
> return ERR_PTR(-EOPNOTSUPP);
Looks good,
Reviewed-by: Dan Williams
[PATCH v4 08/12] dax: Fix incorrect list of data cache aliasing architectures
commit d92576f1167c ("dax: does not work correctly with virtual aliasing
caches")
prevents DAX from building on architectures with virtually aliased
dcache with:
depends on !(ARM || MIPS || SPARC)
This check is too broad (e.g. recent ARMv7 don't have virtually aliased
dcaches), and also misses many other architectures with virtually
aliased data cache.
This is a regression introduced in the v4.0 Linux kernel where the
dax mount option is removed for 32-bit ARMv7 boards which have no data
cache aliasing, and therefore should work fine with FS_DAX.
This was turned into the following check in alloc_dax() by a preparatory
change:
if (ops && (IS_ENABLED(CONFIG_ARM) ||
IS_ENABLED(CONFIG_MIPS) ||
IS_ENABLED(CONFIG_SPARC)))
return NULL;
Use cpu_dcache_is_aliasing() instead to figure out whether the environment
has aliasing data caches.
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing
caches")
Signed-off-by: Mathieu Desnoyers
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: Dan Williams
Cc: Vishal Verma
Cc: Dave Jiang
Cc: Matthew Wilcox
Cc: Arnd Bergmann
Cc: Russell King
Cc: linux-a...@vger.kernel.org
Cc: linux-...@vger.kernel.org
Cc: linux-fsde...@vger.kernel.org
Cc: linux...@kvack.org
Cc: linux-...@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvd...@lists.linux.dev
---
drivers/dax/super.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index ce5bffa86bba..a21a7c262382 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -13,6 +13,7 @@
#include
#include
#include
+#include
#include "dax-private.h"
/**
@@ -455,9 +456,7 @@ struct dax_device *alloc_dax(void *private, const struct
dax_operations *ops)
* except for device-dax (NULL operations pointer), which does
* not use aliased mappings from the kernel.
*/
- if (ops && (IS_ENABLED(CONFIG_ARM) ||
- IS_ENABLED(CONFIG_MIPS) ||
- IS_ENABLED(CONFIG_SPARC)))
+ if (ops && cpu_dcache_is_aliasing())
return ERR_PTR(-EOPNOTSUPP);
if (WARN_ON_ONCE(ops && !ops->zero_page_range))
--
2.39.2
[RFC PATCH v4 08/12] dax: Fix incorrect list of data cache aliasing architectures
commit d92576f1167c ("dax: does not work correctly with virtual aliasing
caches")
prevents DAX from building on architectures with virtually aliased
dcache with:
depends on !(ARM || MIPS || SPARC)
This check is too broad (e.g. recent ARMv7 don't have virtually aliased
dcaches), and also misses many other architectures with virtually
aliased data cache.
This is a regression introduced in the v4.0 Linux kernel where the
dax mount option is removed for 32-bit ARMv7 boards which have no data
cache aliasing, and therefore should work fine with FS_DAX.
This was turned into the following check in alloc_dax() by a preparatory
change:
if (ops && (IS_ENABLED(CONFIG_ARM) ||
IS_ENABLED(CONFIG_MIPS) ||
IS_ENABLED(CONFIG_SPARC)))
return NULL;
Use cpu_dcache_is_aliasing() instead to figure out whether the environment
has aliasing data caches.
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing
caches")
Signed-off-by: Mathieu Desnoyers
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: Dan Williams
Cc: Vishal Verma
Cc: Dave Jiang
Cc: Matthew Wilcox
Cc: Arnd Bergmann
Cc: Russell King
Cc: linux-a...@vger.kernel.org
Cc: linux-...@vger.kernel.org
Cc: linux-fsde...@vger.kernel.org
Cc: linux...@kvack.org
Cc: linux-...@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvd...@lists.linux.dev
---
drivers/dax/super.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index ce5bffa86bba..a21a7c262382 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -13,6 +13,7 @@
#include
#include
#include
+#include
#include "dax-private.h"
/**
@@ -455,9 +456,7 @@ struct dax_device *alloc_dax(void *private, const struct
dax_operations *ops)
* except for device-dax (NULL operations pointer), which does
* not use aliased mappings from the kernel.
*/
- if (ops && (IS_ENABLED(CONFIG_ARM) ||
- IS_ENABLED(CONFIG_MIPS) ||
- IS_ENABLED(CONFIG_SPARC)))
+ if (ops && cpu_dcache_is_aliasing())
return ERR_PTR(-EOPNOTSUPP);
if (WARN_ON_ONCE(ops && !ops->zero_page_range))
--
2.39.2
