dax: check synchronous mapping is supported (32de1484) · Commits · 戴 / test

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> Signed-off-by:

Dan Williams <dan.j.williams@intel.com>

include/linux/dax.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,18 @@ 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)
		{
		@@ -90,6 +102,11 @@ 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;

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