| Message ID | 20240208184913.484340-9-mathieu.desnoyers@efficios.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Introduce cpu_dcache_is_aliasing() to fix DAX regression | expand |
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 <mathieu.desnoyers@efficios.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Linus Torvalds <torvalds@linux-foundation.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: linux-arch@vger.kernel.org > Cc: linux-cxl@vger.kernel.org > Cc: linux-fsdevel@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-xfs@vger.kernel.org > Cc: dm-devel@lists.linux.dev > Cc: nvdimm@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); Looks good, Reviewed-by: Dan Williams <dan.j.williams@intel.com>
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))
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.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.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: linux-arch@vger.kernel.org Cc: linux-cxl@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: dm-devel@lists.linux.dev Cc: nvdimm@lists.linux.dev --- drivers/dax/super.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)