@@ -942,12 +942,6 @@ void dput_to_list(struct dentry *dentry, struct list_head *list)
spin_unlock(&dentry->d_lock);
}
-/* This must be called with d_lock held */
-static inline void __dget_dlock(struct dentry *dentry)
-{
- dentry->d_lockref.count++;
-}
-
static inline void __dget(struct dentry *dentry)
{
lockref_get(&dentry->d_lockref);
@@ -1034,7 +1028,7 @@ static struct dentry *__d_find_alias(struct inode *inode)
hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
spin_lock(&alias->d_lock);
if (!d_unhashed(alias)) {
- __dget_dlock(alias);
+ dget_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
@@ -1707,7 +1701,7 @@ static enum d_walk_ret find_submount(void *_data, struct dentry *dentry)
{
struct dentry **victim = _data;
if (d_mountpoint(dentry)) {
- __dget_dlock(dentry);
+ dget_dlock(dentry);
*victim = dentry;
return D_WALK_QUIT;
}
@@ -1853,7 +1847,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
* don't need child lock because it is not subject
* to concurrency here
*/
- __dget_dlock(parent);
+ dget_dlock(parent);
dentry->d_parent = parent;
list_add(&dentry->d_child, &parent->d_subdirs);
spin_unlock(&parent->d_lock);
@@ -2851,7 +2845,7 @@ struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
spin_unlock(&alias->d_lock);
alias = NULL;
} else {
- __dget_dlock(alias);
+ dget_dlock(alias);
__d_rehash(alias);
spin_unlock(&alias->d_lock);
}
@@ -300,20 +300,28 @@ extern char *dentry_path(const struct dentry *, char *, int);
/* Allocation counts.. */
/**
- * dget, dget_dlock - get a reference to a dentry
+ * dget_dlock - get a reference to a dentry
* @dentry: dentry to get a reference to
*
- * Given a dentry or %NULL pointer increment the reference count
- * if appropriate and return the dentry. A dentry will not be
- * destroyed when it has references.
+ * Given a dentry, increment the reference count and return the
+ * dentry.
+ *
+ * Context: @dentry->d_lock must be held.
*/
static inline struct dentry *dget_dlock(struct dentry *dentry)
{
- if (dentry)
- dentry->d_lockref.count++;
+ dentry->d_lockref.count++;
return dentry;
}
+/**
+ * dget - get a reference to a dentry
+ * @dentry: dentry to get a reference to
+ *
+ * Given a dentry or %NULL pointer increment the reference count
+ * if appropriate and return the dentry. A dentry will not be
+ * destroyed when it has references.
+ */
static inline struct dentry *dget(struct dentry *dentry)
{
if (dentry)
dget_dlock() requires dentry->d_lock to be held when called, yet contains a NULL check for dentry. An audit of all calls to dget_dlock() shows that it is never called with a NULL pointer (as spin_lock()/spin_unlock() would crash in these cases): $ git grep -W '\<dget_dlock\>' arch/powerpc/platforms/cell/spufs/inode.c- spin_lock(&dentry->d_lock); arch/powerpc/platforms/cell/spufs/inode.c- if (simple_positive(dentry)) { arch/powerpc/platforms/cell/spufs/inode.c: dget_dlock(dentry); fs/autofs/expire.c- spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); fs/autofs/expire.c- if (simple_positive(child)) { fs/autofs/expire.c: dget_dlock(child); fs/autofs/root.c: dget_dlock(active); fs/autofs/root.c- spin_unlock(&active->d_lock); fs/autofs/root.c: dget_dlock(expiring); fs/autofs/root.c- spin_unlock(&expiring->d_lock); fs/ceph/dir.c- if (!spin_trylock(&dentry->d_lock)) fs/ceph/dir.c- continue; [...] fs/ceph/dir.c: dget_dlock(dentry); fs/ceph/mds_client.c- spin_lock(&alias->d_lock); [...] fs/ceph/mds_client.c: dn = dget_dlock(alias); fs/configfs/inode.c- spin_lock(&dentry->d_lock); fs/configfs/inode.c- if (simple_positive(dentry)) { fs/configfs/inode.c: dget_dlock(dentry); fs/libfs.c: found = dget_dlock(d); fs/libfs.c- spin_unlock(&d->d_lock); fs/libfs.c: found = dget_dlock(child); fs/libfs.c- spin_unlock(&child->d_lock); fs/libfs.c: child = dget_dlock(d); fs/libfs.c- spin_unlock(&d->d_lock); fs/ocfs2/dcache.c: dget_dlock(dentry); fs/ocfs2/dcache.c- spin_unlock(&dentry->d_lock); include/linux/dcache.h:static inline struct dentry *dget_dlock(struct dentry *dentry) After taking out the NULL check, dget_dlock() becomes almost identical to __dget_dlock(); the only difference is that dget_dlock() returns the dentry that was passed in. These are static inline helpers, so we can rely on the compiler to discard unused return values. We can therefore also remove __dget_dlock() and replace calls to it by dget_dlock(). Also fix up and improve the kerneldoc comments while we're at it. Testing: x86 defconfig build + boot; make htmldocs for the kerneldoc warning. objdump shows there are code generation changes. Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: linux-fsdevel@vger.kernel.org Cc: Nick Piggin <npiggin@kernel.dk> Cc: Waiman Long <Waiman.Long@hp.com> Cc: linux-doc@vger.kernel.org Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> --- fs/dcache.c | 14 ++++---------- include/linux/dcache.h | 20 ++++++++++++++------ 2 files changed, 18 insertions(+), 16 deletions(-)