Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Mathieu Desnoyers <> | Subject | [RFC PATCH v3 4/4] dax: Fix incorrect list of data cache aliasing architectures | Date | Wed, 31 Jan 2024 11:25:33 -0500 |
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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 v5.13 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 (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.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-mm@kvack.org Cc: linux-arch@vger.kernel.org Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@armlinux.org.uk> Cc: nvdimm@lists.linux.dev Cc: linux-cxl@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: dm-devel@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 e9f397b8a5a3..8c3a6e8e6334 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" /** @@ -446,9 +447,7 @@ struct dax_device *alloc_dax(void *private, const struct dax_operations *ops) int minor; /* Unavailable on architectures with virtually aliased data caches. */ - if (IS_ENABLED(CONFIG_ARM) || - IS_ENABLED(CONFIG_MIPS) || - IS_ENABLED(CONFIG_SPARC)) + if (cpu_dcache_is_aliasing()) return NULL; if (WARN_ON_ONCE(ops && !ops->zero_page_range)) -- 2.39.2
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