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 <mathieu.desnoy...@efficios.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Vishal Verma <vishal.l.ve...@intel.com>
Cc: Dave Jiang <dave.ji...@intel.com>
Cc: Matthew Wilcox <wi...@infradead.org>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Russell King <li...@armlinux.org.uk>
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 <linux/uio.h>
#include <linux/dax.h>
#include <linux/fs.h>
+#include <linux/cacheinfo.h>
#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
