From 8966be90304b394fd6a2c5af7b6b3abe2df3889c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 2 Mar 2012 14:23:30 -0800 Subject: vfs: trivial __d_lookup_rcu() cleanups These don't change any semantics, but they clean up the code a bit and mark some arguments appropriately 'const'. They came up as I was doing the word-at-a-time dcache name accessor code, and cleaning this up now allows me to send out a smaller relevant interesting patch for the experimental stuff. Signed-off-by: Linus Torvalds --- fs/dcache.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index fe19ac13f75f5c..138be96e25b674 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -104,7 +104,7 @@ static unsigned int d_hash_shift __read_mostly; static struct hlist_bl_head *dentry_hashtable __read_mostly; -static inline struct hlist_bl_head *d_hash(struct dentry *parent, +static inline struct hlist_bl_head *d_hash(const struct dentry *parent, unsigned long hash) { hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES; @@ -1717,8 +1717,9 @@ EXPORT_SYMBOL(d_add_ci); * child is looked up. Thus, an interlocking stepping of sequence lock checks * is formed, giving integrity down the path walk. */ -struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, - unsigned *seq, struct inode **inode) +struct dentry *__d_lookup_rcu(const struct dentry *parent, + const struct qstr *name, + unsigned *seqp, struct inode **inode) { unsigned int len = name->len; unsigned int hash = name->hash; @@ -1748,6 +1749,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, * See Documentation/filesystems/path-lookup.txt for more details. */ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { + unsigned seq; struct inode *i; const char *tname; int tlen; @@ -1756,7 +1758,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, continue; seqretry: - *seq = read_seqcount_begin(&dentry->d_seq); + seq = read_seqcount_begin(&dentry->d_seq); if (dentry->d_parent != parent) continue; if (d_unhashed(dentry)) @@ -1771,7 +1773,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, * edge of memory when walking. If we could load this * atomically some other way, we could drop this check. */ - if (read_seqcount_retry(&dentry->d_seq, *seq)) + if (read_seqcount_retry(&dentry->d_seq, seq)) goto seqretry; if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { if (parent->d_op->d_compare(parent, *inode, @@ -1788,6 +1790,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, * order to do anything useful with the returned dentry * anyway. */ + *seqp = seq; *inode = i; return dentry; } -- cgit 1.2.3-korg From 5483f18e986ed5267b923bec12b407845181350b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 4 Mar 2012 15:51:42 -0800 Subject: vfs: move dentry_cmp from to fs/dcache.c It's only used inside fs/dcache.c, and we're going to play games with it for the word-at-a-time patches. This time we really don't even want to export it, because it really is an internal function to fs/dcache.c, and has been since it was introduced. Having it in that extremely hot header file (it's included in pretty much everything, thanks to ) is a disaster for testing different versions, and is utterly pointless. We really should have some kind of header file diet thing, where we figure out which parts of header files are really better off private and only result in more expensive compiles. Signed-off-by: Linus Torvalds --- fs/dcache.c | 20 ++++++++++++++++++++ include/linux/dcache.h | 20 -------------------- 2 files changed, 20 insertions(+), 20 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index 138be96e25b674..bcbdb33fcc205a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -137,6 +137,26 @@ int proc_nr_dentry(ctl_table *table, int write, void __user *buffer, } #endif +/* + * Compare 2 name strings, return 0 if they match, otherwise non-zero. + * The strings are both count bytes long, and count is non-zero. + */ +static inline int dentry_cmp(const unsigned char *cs, size_t scount, + const unsigned char *ct, size_t tcount) +{ + if (scount != tcount) + return 1; + + do { + if (*cs != *ct) + return 1; + cs++; + ct++; + tcount--; + } while (tcount); + return 0; +} + static void __d_free(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 4270bedd230849..ff5f5256d175c8 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -47,26 +47,6 @@ struct dentry_stat_t { }; extern struct dentry_stat_t dentry_stat; -/* - * Compare 2 name strings, return 0 if they match, otherwise non-zero. - * The strings are both count bytes long, and count is non-zero. - */ -static inline int dentry_cmp(const unsigned char *cs, size_t scount, - const unsigned char *ct, size_t tcount) -{ - if (scount != tcount) - return 1; - - do { - if (*cs != *ct) - return 1; - cs++; - ct++; - tcount--; - } while (tcount); - return 0; -} - /* Name hashing routines. Initial hash value */ /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ #define init_name_hash() 0 -- cgit 1.2.3-korg