[PATCH 0/4] Const char cleanups

[PATCH 0/4] Const char cleanups

[David Sterba]

A handful of char -> const char changes spotted during other cleanups.

David Sterba (4):
      btrfs: constify device path passed to relevant helpers
      btrfs: constify input buffer of btrfs_csum_data
      btrfs: constify buffers used by compression helpers
      btrfs: constify name of subvolume in creation helpers

 fs/btrfs/compression.c |  2 +-
 fs/btrfs/compression.h |  2 +-
 fs/btrfs/dev-replace.c |  5 +++--
 fs/btrfs/dev-replace.h |  5 +++--
 fs/btrfs/disk-io.c     |  4 ++--
 fs/btrfs/disk-io.h     |  2 +-
 fs/btrfs/ioctl.c       |  6 +++---
 fs/btrfs/lzo.c         |  2 +-
 fs/btrfs/volumes.c     | 18 ++++++++++--------
 fs/btrfs/volumes.h     | 12 ++++++------
 10 files changed, 31 insertions(+), 27 deletions(-)

[PATCH 1/4] btrfs: constify device path passed to relevant helpers

[David Sterba]

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/dev-replace.c |  5 +++--
 fs/btrfs/dev-replace.h |  5 +++--
 fs/btrfs/volumes.c     | 18 ++++++++++--------
 fs/btrfs/volumes.h     | 12 ++++++------
 4 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 5de280b9ad73..e653921f05d9 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -304,8 +304,9 @@ void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info)
 		dev_replace->cursor_left_last_write_of_item;
 }
 
-int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, char *tgtdev_name,
-				u64 srcdevid, char *srcdev_name, int read_src)
+int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
+		const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
+		int read_src)
 {
 	struct btrfs_root *root = fs_info->dev_root;
 	struct btrfs_trans_handle *trans;
diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
index 54ea12bda15b..f94a76844ae7 100644
--- a/fs/btrfs/dev-replace.h
+++ b/fs/btrfs/dev-replace.h
@@ -27,8 +27,9 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
 void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info);
 int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
 			    struct btrfs_ioctl_dev_replace_args *args);
-int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, char *tgtdev_name,
-				u64 srcdevid, char *srcdev_name, int read_src);
+int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
+		const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
+		int read_src);
 void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
 			      struct btrfs_ioctl_dev_replace_args *args);
 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info,
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 1fac98728814..b443cc71830f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1725,7 +1725,7 @@ static int btrfs_add_device(struct btrfs_trans_handle *trans,
  * Function to update ctime/mtime for a given device path.
  * Mainly used for ctime/mtime based probe like libblkid.
  */
-static void update_dev_time(char *path_name)
+static void update_dev_time(const char *path_name)
 {
 	struct file *filp;
 
@@ -1851,7 +1851,8 @@ void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
 		fs_info->fs_devices->latest_bdev = next_device->bdev;
 }
 
-int btrfs_rm_device(struct btrfs_fs_info *fs_info, char *device_path, u64 devid)
+int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
+		u64 devid)
 {
 	struct btrfs_device *device;
 	struct btrfs_fs_devices *cur_devices;
@@ -2091,7 +2092,7 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 }
 
 static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
-				     char *device_path,
+				     const char *device_path,
 				     struct btrfs_device **device)
 {
 	int ret = 0;
@@ -2118,7 +2119,7 @@ static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
 }
 
 int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
-					 char *device_path,
+					 const char *device_path,
 					 struct btrfs_device **device)
 {
 	*device = NULL;
@@ -2151,7 +2152,8 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
  * Lookup a device given by device id, or the path if the id is 0.
  */
 int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
-				 char *devpath, struct btrfs_device **device)
+				 const char *devpath,
+				 struct btrfs_device **device)
 {
 	int ret;
 
@@ -2307,7 +2309,7 @@ static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-int btrfs_init_new_device(struct btrfs_fs_info *fs_info, char *device_path)
+int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path)
 {
 	struct btrfs_root *root = fs_info->dev_root;
 	struct request_queue *q;
@@ -2515,7 +2517,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, char *device_path)
 }
 
 int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
-				  char *device_path,
+				  const char *device_path,
 				  struct btrfs_device *srcdev,
 				  struct btrfs_device **device_out)
 {
@@ -7102,7 +7104,7 @@ int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
 	return 0;
 }
 
-void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
+void btrfs_scratch_superblocks(struct block_device *bdev, const char *device_path)
 {
 	struct buffer_head *bh;
 	struct btrfs_super_block *disk_super;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 24ba6bc3ec34..59be81206dd7 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -422,16 +422,16 @@ void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step);
 void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
 		struct btrfs_device *device, struct btrfs_device *this_dev);
 int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
-					 char *device_path,
+					 const char *device_path,
 					 struct btrfs_device **device);
 int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
-					 char *devpath,
+					 const char *devpath,
 					 struct btrfs_device **device);
 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 					const u64 *devid,
 					const u8 *uuid);
 int btrfs_rm_device(struct btrfs_fs_info *fs_info,
-		    char *device_path, u64 devid);
+		    const char *device_path, u64 devid);
 void btrfs_cleanup_fs_uuids(void);
 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len);
 int btrfs_grow_device(struct btrfs_trans_handle *trans,
@@ -439,9 +439,9 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans,
 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
 				       u8 *uuid, u8 *fsid);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
-int btrfs_init_new_device(struct btrfs_fs_info *fs_info, char *path);
+int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *path);
 int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
-				  char *device_path,
+				  const char *device_path,
 				  struct btrfs_device *srcdev,
 				  struct btrfs_device **device_out);
 int btrfs_balance(struct btrfs_balance_control *bctl,
@@ -474,7 +474,7 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 				      struct btrfs_device *tgtdev);
 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
 					      struct btrfs_device *tgtdev);
-void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path);
+void btrfs_scratch_superblocks(struct block_device *bdev, const char *device_path);
 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
 			   u64 logical, u64 len, int mirror_num);
 unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
-- 
2.10.1

[PATCH 2/4] btrfs: constify input buffer of btrfs_csum_data

[David Sterba]

The function does not modify the input buffer, also update a typecast in
one caller.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/disk-io.c | 4 ++--
 fs/btrfs/disk-io.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2b06f557c176..1b4d737bb908 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -265,7 +265,7 @@ static struct extent_map *btree_get_extent(struct inode *inode,
 	return em;
 }
 
-u32 btrfs_csum_data(char *data, u32 seed, size_t len)
+u32 btrfs_csum_data(const char *data, u32 seed, size_t len)
 {
 	return btrfs_crc32c(seed, data, len);
 }
@@ -3448,7 +3448,7 @@ static int write_dev_supers(struct btrfs_device *device,
 			btrfs_set_super_bytenr(sb, bytenr);
 
 			crc = ~(u32)0;
-			crc = btrfs_csum_data((char *)sb +
+			crc = btrfs_csum_data((const char *)sb +
 					      BTRFS_CSUM_SIZE, crc,
 					      BTRFS_SUPER_INFO_SIZE -
 					      BTRFS_CSUM_SIZE);
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 0be2d4fe705b..2e0ec29bfd69 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -116,7 +116,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
 			  int atomic);
 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);
-u32 btrfs_csum_data(char *data, u32 seed, size_t len);
+u32 btrfs_csum_data(const char *data, u32 seed, size_t len);
 void btrfs_csum_final(u32 crc, u8 *result);
 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 			enum btrfs_wq_endio_type metadata);
-- 
2.10.1

[PATCH 3/4] btrfs: constify buffers used by compression helpers

[David Sterba]

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/compression.c | 2 +-
 fs/btrfs/compression.h | 2 +-
 fs/btrfs/lzo.c         | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 903c32c9eb22..c76312405f5c 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1015,7 +1015,7 @@ void btrfs_exit_compress(void)
  *
  * total_out is the last byte of the buffer
  */
-int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
+int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
 			      unsigned long total_out, u64 disk_start,
 			      struct bio *bio)
 {
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 09879579fbc8..1c700bb20b52 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -32,7 +32,7 @@ int btrfs_compress_pages(int type, struct address_space *mapping,
 			 unsigned long max_out);
 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
 		     unsigned long start_byte, size_t srclen, size_t destlen);
-int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
+int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
 			      unsigned long total_out, u64 disk_start,
 			      struct bio *bio);
 
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 45d26980caf9..e074b85aa054 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -76,7 +76,7 @@ static inline void write_compress_length(char *buf, size_t len)
 	memcpy(buf, &dlen, LZO_LEN);
 }
 
-static inline size_t read_compress_length(char *buf)
+static inline size_t read_compress_length(const char *buf)
 {
 	__le32 dlen;
 
-- 
2.10.1

[PATCH 4/4] btrfs: constify name of subvolume in creation helpers

[David Sterba]

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 717f34f977d5..8449ce435b27 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -434,7 +434,7 @@ int btrfs_is_empty_uuid(u8 *uuid)
 
 static noinline int create_subvol(struct inode *dir,
 				  struct dentry *dentry,
-				  char *name, int namelen,
+				  const char *name, int namelen,
 				  u64 *async_transid,
 				  struct btrfs_qgroup_inherit *inherit)
 {
@@ -832,7 +832,7 @@ static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
  * inside this filesystem so it's quite a bit simpler.
  */
 static noinline int btrfs_mksubvol(const struct path *parent,
-				   char *name, int namelen,
+				   const char *name, int namelen,
 				   struct btrfs_root *snap_src,
 				   u64 *async_transid, bool readonly,
 				   struct btrfs_qgroup_inherit *inherit)
@@ -1625,7 +1625,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 }
 
 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
-				char *name, unsigned long fd, int subvol,
+				const char *name, unsigned long fd, int subvol,
 				u64 *transid, bool readonly,
 				struct btrfs_qgroup_inherit *inherit)
 {
-- 
2.10.1