[PATCH] btrfs: constify structs with op functions or static definitions

[PATCH] btrfs: constify structs with op functions or static definitions

[David Sterba]

There are some op tables that can be easily made const, similarly the
sysfs feature and raid tables. This is motivated by PaX CONSTIFY plugin.

Signed-off-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/compression.c | 2 +-
 fs/btrfs/compression.h | 4 ++--
 fs/btrfs/disk-io.c     | 4 ++--
 fs/btrfs/extent_io.h   | 2 +-
 fs/btrfs/lzo.c         | 2 +-
 fs/btrfs/props.c       | 2 ++
 fs/btrfs/sysfs.c       | 2 +-
 fs/btrfs/transaction.c | 2 +-
 fs/btrfs/volumes.c     | 2 +-
 fs/btrfs/zlib.c        | 2 +-
 10 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index e9df8862012c..e7a94f8cdfd7 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -750,7 +750,7 @@ static int comp_num_workspace[BTRFS_COMPRESS_TYPES];
 static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES];
 static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES];
 
-static struct btrfs_compress_op *btrfs_compress_op[] = {
+static const struct btrfs_compress_op * const btrfs_compress_op[] = {
 	&btrfs_zlib_compress,
 	&btrfs_lzo_compress,
 };
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index d181f70caae0..13a4dc0436c9 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -77,7 +77,7 @@ struct btrfs_compress_op {
 			  size_t srclen, size_t destlen);
 };
 
-extern struct btrfs_compress_op btrfs_zlib_compress;
-extern struct btrfs_compress_op btrfs_lzo_compress;
+extern const struct btrfs_compress_op btrfs_zlib_compress;
+extern const struct btrfs_compress_op btrfs_lzo_compress;
 
 #endif
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8c63419a7f70..4641abccae1f 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -54,7 +54,7 @@
 #include <asm/cpufeature.h>
 #endif
 
-static struct extent_io_ops btree_extent_io_ops;
+static const struct extent_io_ops btree_extent_io_ops;
 static void end_workqueue_fn(struct btrfs_work *work);
 static void free_fs_root(struct btrfs_root *root);
 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
@@ -4239,7 +4239,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
 	return 0;
 }
 
-static struct extent_io_ops btree_extent_io_ops = {
+static const struct extent_io_ops btree_extent_io_ops = {
 	.readpage_end_io_hook = btree_readpage_end_io_hook,
 	.readpage_io_failed_hook = btree_io_failed_hook,
 	.submit_bio_hook = btree_submit_bio_hook,
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index ece9ce87edff..89488ca73f5a 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -97,7 +97,7 @@ struct extent_io_tree {
 	u64 dirty_bytes;
 	int track_uptodate;
 	spinlock_t lock;
-	struct extent_io_ops *ops;
+	const struct extent_io_ops *ops;
 };
 
 struct extent_state {
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 617553cdb7d3..a2f051347731 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -434,7 +434,7 @@ out:
 	return ret;
 }
 
-struct btrfs_compress_op btrfs_lzo_compress = {
+const struct btrfs_compress_op btrfs_lzo_compress = {
 	.alloc_workspace	= lzo_alloc_workspace,
 	.free_workspace		= lzo_free_workspace,
 	.compress_pages		= lzo_compress_pages,
diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c
index 129b1dd28527..dca137b04095 100644
--- a/fs/btrfs/props.c
+++ b/fs/btrfs/props.c
@@ -425,3 +425,5 @@ static const char *prop_compression_extract(struct inode *inode)
 
 	return NULL;
 }
+
+
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 92db3f648df4..577ba5fb1948 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -459,7 +459,7 @@ static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 
-static u64 supported_feature_masks[3] = {
+static const u64 supported_feature_masks[3] = {
 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a605d4e2f2bc..5d68f310a3fb 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -35,7 +35,7 @@
 
 #define BTRFS_ROOT_TRANS_TAG 0
 
-static unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
+static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
 	[TRANS_STATE_RUNNING]		= 0U,
 	[TRANS_STATE_BLOCKED]		= (__TRANS_USERSPACE |
 					   __TRANS_START),
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 50c5a8762aed..5873fe9ba7b1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4129,7 +4129,7 @@ static int btrfs_cmp_device_info(const void *a, const void *b)
 	return 0;
 }
 
-static struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
+static const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 	[BTRFS_RAID_RAID10] = {
 		.sub_stripes	= 2,
 		.dev_stripes	= 1,
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index fb22fd8d8fb8..82990b8f872b 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -403,7 +403,7 @@ next:
 	return ret;
 }
 
-struct btrfs_compress_op btrfs_zlib_compress = {
+const struct btrfs_compress_op btrfs_zlib_compress = {
 	.alloc_workspace	= zlib_alloc_workspace,
 	.free_workspace		= zlib_free_workspace,
 	.compress_pages		= zlib_compress_pages,
-- 
1.8.4.5