From 6fa67e707559303e086303aeecc9e8b91ef497d5 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 31 Jul 2016 16:37:25 -0400
Subject: [PATCH] get rid of 'parent' argument of ->d_compare()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 Documentation/filesystems/Locking            |  2 +-
 Documentation/filesystems/porting            |  7 +++++++
 Documentation/filesystems/vfs.txt            |  2 +-
 drivers/staging/lustre/lustre/llite/dcache.c |  2 +-
 fs/adfs/dir.c                                |  2 +-
 fs/affs/namei.c                              |  8 ++++----
 fs/cifs/dir.c                                |  2 +-
 fs/dcache.c                                  |  4 ++--
 fs/efivarfs/super.c                          |  3 +--
 fs/fat/namei_msdos.c                         |  2 +-
 fs/fat/namei_vfat.c                          |  4 ++--
 fs/hfs/hfs_fs.h                              |  2 +-
 fs/hfs/string.c                              |  2 +-
 fs/hfsplus/hfsplus_fs.h                      |  3 +--
 fs/hfsplus/unicode.c                         |  2 +-
 fs/hpfs/dentry.c                             |  2 +-
 fs/isofs/inode.c                             | 15 ++++++---------
 fs/isofs/namei.c                             |  2 +-
 fs/jfs/namei.c                               |  2 +-
 fs/ncpfs/dir.c                               |  6 +++---
 fs/proc/proc_sysctl.c                        |  2 +-
 include/linux/dcache.h                       |  2 +-
 22 files changed, 40 insertions(+), 38 deletions(-)

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 1b3c39a7de62..d30fb2cb5066 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -12,7 +12,7 @@ prototypes:
 	int (*d_revalidate)(struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
 	int (*d_hash)(const struct dentry *, struct qstr *);
-	int (*d_compare)(const struct dentry *, const struct dentry *,
+	int (*d_compare)(const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(struct dentry *);
 	int (*d_init)(struct dentry *);
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index a5fb89cac615..b1bd05ea66b2 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -585,3 +585,10 @@ in your dentry operations instead.
 	in the instances.  Rationale: !@#!@# security_d_instantiate() needs to be
 	called before we attach dentry to inode and !@#!@##!@$!$#!@#$!@$!@$ smack
 	->d_instantiate() uses not just ->getxattr() but ->setxattr() as well.
+--
+[mandatory]
+	->d_compare() doesn't get parent as a separate argument anymore.  If you
+	used it for finding the struct super_block involved, dentry->d_sb will
+	work just as well; if it's something more complicated, use dentry->d_parent.
+	Just be careful not to assume that fetching it more than once will yield
+	the same value - in RCU mode it could change under you.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 8a196851f01d..9ace359d6cc5 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -931,7 +931,7 @@ struct dentry_operations {
 	int (*d_revalidate)(struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
 	int (*d_hash)(const struct dentry *, struct qstr *);
-	int (*d_compare)(const struct dentry *, const struct dentry *,
+	int (*d_compare)(const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(const struct dentry *);
 	int (*d_init)(struct dentry *);
diff --git a/drivers/staging/lustre/lustre/llite/dcache.c b/drivers/staging/lustre/lustre/llite/dcache.c
index 581a63a0a63e..463b1a360733 100644
--- a/drivers/staging/lustre/lustre/llite/dcache.c
+++ b/drivers/staging/lustre/lustre/llite/dcache.c
@@ -78,7 +78,7 @@ static void ll_release(struct dentry *de)
  * INVALID) so d_lookup() matches it, but we have no lock on it (so
  * lock_match() fails) and we spin around real_lookup().
  */
-static int ll_dcompare(const struct dentry *parent, const struct dentry *dentry,
+static int ll_dcompare(const struct dentry *dentry,
 		       unsigned int len, const char *str,
 		       const struct qstr *name)
 {
diff --git a/fs/adfs/dir.c b/fs/adfs/dir.c
index bec25f7017c0..c30a5a65cbb5 100644
--- a/fs/adfs/dir.c
+++ b/fs/adfs/dir.c
@@ -227,7 +227,7 @@ adfs_hash(const struct dentry *parent, struct qstr *qstr)
  * requirements of the underlying filesystem.
  */
 static int
-adfs_compare(const struct dentry *parent, const struct dentry *dentry,
+adfs_compare(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	int i;
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 27ca732680d9..a2d68f828d53 100644
--- a/fs/affs/namei.c
+++ b/fs/affs/namei.c
@@ -14,11 +14,11 @@ typedef int (*toupper_t)(int);
 
 static int	 affs_toupper(int ch);
 static int	 affs_hash_dentry(const struct dentry *, struct qstr *);
-static int       affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+static int       affs_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
 static int	 affs_intl_toupper(int ch);
 static int	 affs_intl_hash_dentry(const struct dentry *, struct qstr *);
-static int       affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+static int       affs_intl_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
 
 const struct dentry_operations affs_dentry_operations = {
@@ -131,7 +131,7 @@ static inline int __affs_compare_dentry(unsigned int len,
 }
 
 static int
-affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+affs_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 
@@ -140,7 +140,7 @@ affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 }
 
 static int
-affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+affs_intl_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	return __affs_compare_dentry(len, str, name, affs_intl_toupper,
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index cf394da87cd4..4716c54dbfc6 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -903,7 +903,7 @@ static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
 	return 0;
 }
 
-static int cifs_ci_compare(const struct dentry *parent, const struct dentry *dentry,
+static int cifs_ci_compare(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
diff --git a/fs/dcache.c b/fs/dcache.c
index d9450bd496ac..32a9209c8138 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2047,7 +2047,7 @@ static inline bool d_same_name(const struct dentry *dentry,
 			return false;
 		return dentry_cmp(dentry, name->name, name->len) == 0;
 	}
-	return parent->d_op->d_compare(parent, dentry,
+	return parent->d_op->d_compare(dentry,
 				       dentry->d_name.len, dentry->d_name.name,
 				       name) == 0;
 }
@@ -2150,7 +2150,7 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
 				cpu_relax();
 				goto seqretry;
 			}
-			if (parent->d_op->d_compare(parent, dentry,
+			if (parent->d_op->d_compare(dentry,
 						    tlen, tname, name) != 0)
 				continue;
 		} else {
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index a5e607e8f056..688ccc16b702 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -45,8 +45,7 @@ static struct super_block *efivarfs_sb;
  * So we need to perform a case-sensitive match on part 1 and a
  * case-insensitive match on part 2.
  */
-static int efivarfs_d_compare(const struct dentry *parent,
-			      const struct dentry *dentry,
+static int efivarfs_d_compare(const struct dentry *dentry,
 			      unsigned int len, const char *str,
 			      const struct qstr *name)
 {
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 0f177127e4d6..664655b2c55f 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -162,7 +162,7 @@ static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
  * Compare two msdos names. If either of the names are invalid,
  * we fall back to doing the standard name comparison.
  */
-static int msdos_cmp(const struct dentry *parent, const struct dentry *dentry,
+static int msdos_cmp(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index e60a90841381..0335e504e65a 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -138,7 +138,7 @@ static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
 /*
  * Case insensitive compare of two vfat names.
  */
-static int vfat_cmpi(const struct dentry *parent, const struct dentry *dentry,
+static int vfat_cmpi(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
@@ -157,7 +157,7 @@ static int vfat_cmpi(const struct dentry *parent, const struct dentry *dentry,
 /*
  * Case sensitive compare of two vfat names.
  */
-static int vfat_cmp(const struct dentry *parent, const struct dentry *dentry,
+static int vfat_cmp(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	unsigned int alen, blen;
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index ee2f385811c8..f28d7a259105 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -233,7 +233,7 @@ extern const struct dentry_operations hfs_dentry_operations;
 extern int hfs_hash_dentry(const struct dentry *, struct qstr *);
 extern int hfs_strcmp(const unsigned char *, unsigned int,
 		      const unsigned char *, unsigned int);
-extern int hfs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+extern int hfs_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
 
 /* trans.c */
diff --git a/fs/hfs/string.c b/fs/hfs/string.c
index ec9f164c35a5..3912209153a8 100644
--- a/fs/hfs/string.c
+++ b/fs/hfs/string.c
@@ -92,7 +92,7 @@ int hfs_strcmp(const unsigned char *s1, unsigned int len1,
  * Test for equality of two strings in the HFS filename character ordering.
  * return 1 on failure and 0 on success
  */
-int hfs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+int hfs_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	const unsigned char *n1, *n2;
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 047245bd2cd6..e95c01f1d62e 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -520,8 +520,7 @@ int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr,
 int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr,
 		    int max_unistr_len, const char *astr, int len);
 int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str);
-int hfsplus_compare_dentry(const struct dentry *parent,
-			   const struct dentry *dentry, unsigned int len,
+int hfsplus_compare_dentry(const struct dentry *dentry, unsigned int len,
 			   const char *str, const struct qstr *name);
 
 /* wrapper.c */
diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
index 509d7e231460..e563939882f3 100644
--- a/fs/hfsplus/unicode.c
+++ b/fs/hfsplus/unicode.c
@@ -385,7 +385,7 @@ int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str)
  * Composed unicode characters are decomposed and case-folding is performed
  * if the appropriate bits are (un)set on the superblock.
  */
-int hfsplus_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+int hfsplus_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct super_block *sb = dentry->d_sb;
diff --git a/fs/hpfs/dentry.c b/fs/hpfs/dentry.c
index a804300f4dce..bb87d65f0d97 100644
--- a/fs/hpfs/dentry.c
+++ b/fs/hpfs/dentry.c
@@ -34,7 +34,7 @@ static int hpfs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 	return 0;
 }
 
-static int hpfs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+static int hpfs_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	unsigned al = len;
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 761fade7680f..ad0c745ebad7 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -29,18 +29,15 @@
 #define BEQUIET
 
 static int isofs_hashi(const struct dentry *parent, struct qstr *qstr);
-static int isofs_dentry_cmpi(const struct dentry *parent,
-		const struct dentry *dentry,
+static int isofs_dentry_cmpi(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
 
 #ifdef CONFIG_JOLIET
 static int isofs_hashi_ms(const struct dentry *parent, struct qstr *qstr);
 static int isofs_hash_ms(const struct dentry *parent, struct qstr *qstr);
-static int isofs_dentry_cmpi_ms(const struct dentry *parent,
-		const struct dentry *dentry,
+static int isofs_dentry_cmpi_ms(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
-static int isofs_dentry_cmp_ms(const struct dentry *parent,
-		const struct dentry *dentry,
+static int isofs_dentry_cmp_ms(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name);
 #endif
 
@@ -235,7 +232,7 @@ isofs_hashi(const struct dentry *dentry, struct qstr *qstr)
 }
 
 static int
-isofs_dentry_cmpi(const struct dentry *parent, const struct dentry *dentry,
+isofs_dentry_cmpi(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	return isofs_dentry_cmp_common(len, str, name, 0, 1);
@@ -276,14 +273,14 @@ isofs_hashi_ms(const struct dentry *dentry, struct qstr *qstr)
 }
 
 static int
-isofs_dentry_cmp_ms(const struct dentry *parent, const struct dentry *dentry,
+isofs_dentry_cmp_ms(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	return isofs_dentry_cmp_common(len, str, name, 1, 0);
 }
 
 static int
-isofs_dentry_cmpi_ms(const struct dentry *parent, const struct dentry *dentry,
+isofs_dentry_cmpi_ms(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	return isofs_dentry_cmp_common(len, str, name, 1, 1);
diff --git a/fs/isofs/namei.c b/fs/isofs/namei.c
index 7b543e6b6526..aee592767f1d 100644
--- a/fs/isofs/namei.c
+++ b/fs/isofs/namei.c
@@ -22,7 +22,7 @@ isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
 	qstr.len = dlen;
 	if (likely(!dentry->d_op))
 		return dentry->d_name.len != dlen || memcmp(dentry->d_name.name, compare, dlen);
-	return dentry->d_op->d_compare(NULL, NULL, dentry->d_name.len, dentry->d_name.name, &qstr);
+	return dentry->d_op->d_compare(NULL, dentry->d_name.len, dentry->d_name.name, &qstr);
 }
 
 /*
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 04baf0dfc40c..814b0c58016c 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1572,7 +1572,7 @@ static int jfs_ci_hash(const struct dentry *dir, struct qstr *this)
 	return 0;
 }
 
-static int jfs_ci_compare(const struct dentry *parent, const struct dentry *dentry,
+static int jfs_ci_compare(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	int i, result = 1;
diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c
index 9add7ab747a5..17de5c13dfae 100644
--- a/fs/ncpfs/dir.c
+++ b/fs/ncpfs/dir.c
@@ -74,7 +74,7 @@ const struct inode_operations ncp_dir_inode_operations =
  */
 static int ncp_lookup_validate(struct dentry *, unsigned int);
 static int ncp_hash_dentry(const struct dentry *, struct qstr *);
-static int ncp_compare_dentry(const struct dentry *, const struct dentry *,
+static int ncp_compare_dentry(const struct dentry *,
 		unsigned int, const char *, const struct qstr *);
 static int ncp_delete_dentry(const struct dentry *);
 static void ncp_d_prune(struct dentry *dentry);
@@ -154,7 +154,7 @@ ncp_hash_dentry(const struct dentry *dentry, struct qstr *this)
  * the callers will handle races.
  */
 static int
-ncp_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
+ncp_compare_dentry(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct inode *pinode;
@@ -162,7 +162,7 @@ ncp_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 	if (len != name->len)
 		return 1;
 
-	pinode = d_inode_rcu(parent);
+	pinode = d_inode_rcu(dentry->d_parent);
 	if (!pinode)
 		return 1;
 
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b59db94d2ff4..30bb00130d0f 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -834,7 +834,7 @@ static int sysctl_is_seen(struct ctl_table_header *p)
 	return res;
 }
 
-static int proc_sys_compare(const struct dentry *parent, const struct dentry *dentry,
+static int proc_sys_compare(const struct dentry *dentry,
 		unsigned int len, const char *str, const struct qstr *name)
 {
 	struct ctl_table_header *head;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 98044a8d1487..107d9abe7166 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -130,7 +130,7 @@ struct dentry_operations {
 	int (*d_revalidate)(struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
 	int (*d_hash)(const struct dentry *, struct qstr *);
-	int (*d_compare)(const struct dentry *, const struct dentry *,
+	int (*d_compare)(const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(const struct dentry *);
 	int (*d_init)(struct dentry *);
-- 
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