The quilt patch titled
     Subject: dax: fix incorrect list of data cache aliasing architectures
has been removed from the -mm tree.  Its filename was
     dax-fix-incorrect-list-of-data-cache-aliasing-architectures.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Subject: dax: fix incorrect list of data cache aliasing architectures
Date: Thu, 15 Feb 2024 09:46:33 -0500

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.

Link: 
https://lkml.kernel.org/r/20240215144633.96437-10-mathieu.desnoy...@efficios.com
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing 
caches")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
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: Alasdair Kergon <a...@redhat.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Dave Chinner <da...@fromorbit.com>
Cc: Heiko Carstens <h...@linux.ibm.com>
Cc: kernel test robot <l...@intel.com>
Cc: Michael Sclafani <dm-devel@lists.linux.dev>
Cc: Mike Snitzer <snit...@kernel.org>
Cc: Mikulas Patocka <mpato...@redhat.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
---

 drivers/dax/super.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- 
a/drivers/dax/super.c~dax-fix-incorrect-list-of-data-cache-aliasing-architectures
+++ a/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"
 
 /**
@@ -456,9 +457,7 @@ struct dax_device *alloc_dax(void *priva
         * 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))
_

Patches currently in -mm which might be from mathieu.desnoy...@efficios.com are



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