[PATCH 07/27] quota: port to const mnt_idmap

[Christian Brauner <brauner@kernel.org>]

Convert to const struct mnt_idmap.

A mount's idmapping is immutable. The only thing that is allowed to be
modified afterwards is the reference count and that is hidden behind
mnt_idmap_get() and mnt_idmap_put(). Everything else only ever reads
from the idmapping. This is the same model that struct cred uses and the
idmapping is also rather sensitive.

So make the idmap argument const wherever we can. The conversion is done
from the bottom up so callers can continue to pass a non-const pointer
to a const parameter until the conversion is finished.

No functional changes.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/quota/dquot.c         | 2 +-
 include/linux/quotaops.h | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 204afc5e984b..c5e9c4e24d68 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2079,7 +2079,7 @@ EXPORT_SYMBOL(__dquot_transfer);
 /* Wrapper for transferring ownership of an inode for uid/gid only
  * Called from FSXXX_setattr()
  */
-int dquot_transfer(struct mnt_idmap *idmap, struct inode *inode,
+int dquot_transfer(const struct mnt_idmap *idmap, struct inode *inode,
 		   struct iattr *iattr)
 {
 	struct dquot *transfer_to[MAXQUOTAS] = {};
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index f9c0f9d7c9d9..0c64ca674e77 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -20,7 +20,7 @@ static inline struct quota_info *sb_dqopt(struct super_block *sb)
 }
 
 /* i_rwsem must being held */
-static inline bool is_quota_modification(struct mnt_idmap *idmap,
+static inline bool is_quota_modification(const struct mnt_idmap *idmap,
 					 struct inode *inode, struct iattr *ia)
 {
 	return ((ia->ia_valid & ATTR_SIZE) ||
@@ -109,7 +109,7 @@ int dquot_set_dqblk(struct super_block *sb, struct kqid id,
 		struct qc_dqblk *di);
 
 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
-int dquot_transfer(struct mnt_idmap *idmap, struct inode *inode,
+int dquot_transfer(const struct mnt_idmap *idmap, struct inode *inode,
 		   struct iattr *iattr);
 
 static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
@@ -229,7 +229,7 @@ static inline void dquot_free_inode(struct inode *inode)
 {
 }
 
-static inline int dquot_transfer(struct mnt_idmap *idmap,
+static inline int dquot_transfer(const struct mnt_idmap *idmap,
 				 struct inode *inode, struct iattr *iattr)
 {
 	return 0;

-- 
2.53.0