[v15,5/7] dax: check synchronous mapping is supported
diff mbox series

Message ID 20190705140328.20190-6-pagupta@redhat.com
State Accepted
Headers show
Series
  • virtio pmem driver
Related show

Commit Message

Pankaj Gupta July 5, 2019, 2:03 p.m. UTC
This patch introduces 'daxdev_mapping_supported' helper
which checks if 'MAP_SYNC' is supported with filesystem
mapping. It also checks if corresponding dax_device is
synchronous. Virtio pmem device is asynchronous and
does not not support VM_SYNC.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 include/linux/dax.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Patch
diff mbox series

diff --git a/include/linux/dax.h b/include/linux/dax.h
index 86fc55c99b58..d1bea3979b5a 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -53,6 +53,18 @@  static inline void set_dax_synchronous(struct dax_device *dax_dev)
 {
 	__set_dax_synchronous(dax_dev);
 }
+/*
+ * Check if given mapping is supported by the file / underlying device.
+ */
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+					     struct dax_device *dax_dev)
+{
+	if (!(vma->vm_flags & VM_SYNC))
+		return true;
+	if (!IS_DAX(file_inode(vma->vm_file)))
+		return false;
+	return dax_synchronous(dax_dev);
+}
 #else
 static inline struct dax_device *dax_get_by_host(const char *host)
 {
@@ -87,6 +99,11 @@  static inline bool dax_synchronous(struct dax_device *dax_dev)
 static inline void set_dax_synchronous(struct dax_device *dax_dev)
 {
 }
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+				struct dax_device *dax_dev)
+{
+	return !(vma->vm_flags & VM_SYNC);
+}
 #endif
 
 struct writeback_control;