[RFC PATCH 3/7] erofs: Use dax_is_supported()

[Mathieu Desnoyers]

Use dax_is_supported() to validate whether the architecture has
virtually aliased data caches at mount time.

This is relevant for architectures which require a dynamic check
to validate whether they have virtually aliased data caches
(ARCH_HAS_CACHE_ALIASING_DYNAMIC=y).

Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Gao Xiang <xiang@xxxxxxxxxx>
Cc: Chao Yu <chao@xxxxxxxxxx>
Cc: Yue Hu <huyue2@xxxxxxxxxxx>
Cc: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
Cc: linux-erofs@xxxxxxxxxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: nvdimm@xxxxxxxxxxxxxxx
Cc: linux-cxl@xxxxxxxxxxxxxxx
---
 fs/erofs/super.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3789d6224513..bd88221f1ad7 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -419,9 +419,13 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = {
 
 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
 {
-#ifdef CONFIG_FS_DAX
 	struct erofs_fs_context *ctx = fc->fs_private;
 
+	if (!dax_is_supported()) {
+		errorfc(fc, "dax options not supported");
+		return false;
+	}
+
 	switch (mode) {
 	case EROFS_MOUNT_DAX_ALWAYS:
 		warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
@@ -436,10 +440,6 @@ static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
 		DBG_BUGON(1);
 		return false;
 	}
-#else
-	errorfc(fc, "dax options not supported");
-	return false;
-#endif
 }
 
 static int erofs_fc_parse_param(struct fs_context *fc,
-- 
2.39.2