[PATCH 10/19] fuse: Introduce setupmapping/removemapping commands

[Vivek Goyal]

Introduce two new fuse commands to setup/remove memory mappings. This
will be used to setup/tear down file mapping in dax window.

Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxxxx>
---
 include/uapi/linux/fuse.h | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 4461fd640cf2..7c2ad3d418df 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -426,6 +426,8 @@ enum fuse_opcode {
 	FUSE_RENAME2		= 45,
 	FUSE_LSEEK		= 46,
 	FUSE_COPY_FILE_RANGE	= 47,
+	FUSE_SETUPMAPPING       = 48,
+	FUSE_REMOVEMAPPING      = 49,
 
 	/* CUSE specific operations */
 	CUSE_INIT		= 4096,
@@ -850,4 +852,41 @@ struct fuse_copy_file_range_in {
 	uint64_t	flags;
 };
 
+#define FUSE_SETUPMAPPING_ENTRIES 8
+#define FUSE_SETUPMAPPING_FLAG_WRITE (1ull << 0)
+struct fuse_setupmapping_in {
+	/* An already open handle */
+	uint64_t	fh;
+	/* Offset into the file to start the mapping */
+	uint64_t	foffset;
+	/* Length of mapping required */
+	uint64_t	len;
+	/* Flags, FUSE_SETUPMAPPING_FLAG_* */
+	uint64_t	flags;
+	/* Offset in Memory Window */
+	uint64_t	moffset;
+};
+
+struct fuse_setupmapping_out {
+	/* Offsets into the cache of mappings */
+	uint64_t	coffset[FUSE_SETUPMAPPING_ENTRIES];
+        /* Lengths of each mapping */
+        uint64_t	len[FUSE_SETUPMAPPING_ENTRIES];
+};
+
+struct fuse_removemapping_in {
+	/* number of fuse_removemapping_one follows */
+	uint32_t        count;
+};
+
+struct fuse_removemapping_one {
+	/* Offset into the dax window start the unmapping */
+	uint64_t        moffset;
+        /* Length of mapping required */
+        uint64_t	len;
+};
+
+#define FUSE_REMOVEMAPPING_MAX_ENTRY   \
+		(PAGE_SIZE / sizeof(struct fuse_removemapping_one))
+
 #endif /* _LINUX_FUSE_H */
-- 
2.20.1