Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / drivers / dax / super.c

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index a0244f6..aca71d7 100644 (file)
--- 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"
 
 /**
@@ -319,6 +320,11 @@ EXPORT_SYMBOL_GPL(dax_alive);
  * that any fault handlers or operations that might have seen
  * dax_alive(), have completed.  Any operations that start after
  * synchronize_srcu() has run will abort upon seeing !dax_alive().
+ *
+ * Note, because alloc_dax() returns an ERR_PTR() on error, callers
+ * typically store its result into a local variable in order to check
+ * the result. Therefore, care must be taken to populate the struct
+ * device dax_dev field make sure the dax_dev is not leaked.
  */
 void kill_dax(struct dax_device *dax_dev)
 {
@@ -446,6 +452,14 @@ struct dax_device *alloc_dax(void *private, const struct dax_operations *ops)
        dev_t devt;
        int minor;
 
+       /*
+        * Unavailable on architectures with virtually aliased data caches,
+        * except for device-dax (NULL operations pointer), which does
+        * not use aliased mappings from the kernel.
+        */
+       if (ops && cpu_dcache_is_aliasing())
+               return ERR_PTR(-EOPNOTSUPP);
+
        if (WARN_ON_ONCE(ops && !ops->zero_page_range))
                return ERR_PTR(-EINVAL);