The patch titled
Subject: autofs4: don't take spinlock when not needed in autofs4_lookup_expiring
has been removed from the -mm tree. Its filename was
autofs4-dont-take-spinlock-when-not-needed-in-autofs4_lookup_expiring.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: NeilBrown <neilb@xxxxxxx>
Subject: autofs4: don't take spinlock when not needed in autofs4_lookup_expiring
If the expiring_list is empty, we can avoid a costly spinlock in the
rcu-walk path through autofs4_d_manage (once the rest of the path becomes
rcu-walk friendly).
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Reviewed-by: Ian Kent <raven@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/autofs4/root.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN fs/autofs4/root.c~autofs4-dont-take-spinlock-when-not-needed-in-autofs4_lookup_expiring fs/autofs4/root.c
--- a/fs/autofs4/root.c~autofs4-dont-take-spinlock-when-not-needed-in-autofs4_lookup_expiring
+++ a/fs/autofs4/root.c
@@ -166,8 +166,10 @@ static struct dentry *autofs4_lookup_act
const unsigned char *str = name->name;
struct list_head *p, *head;
- spin_lock(&sbi->lookup_lock);
head = &sbi->active_list;
+ if (list_empty(head))
+ return NULL;
+ spin_lock(&sbi->lookup_lock);
list_for_each(p, head) {
struct autofs_info *ino;
struct dentry *active;
@@ -218,8 +220,10 @@ static struct dentry *autofs4_lookup_exp
const unsigned char *str = name->name;
struct list_head *p, *head;
- spin_lock(&sbi->lookup_lock);
head = &sbi->expiring_list;
+ if (list_empty(head))
+ return NULL;
+ spin_lock(&sbi->lookup_lock);
list_for_each(p, head) {
struct autofs_info *ino;
struct dentry *expiring;
_
Patches currently in -mm which might be from neilb@xxxxxxx are
origin.patch
linux-next.patch
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