Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Fixes and improvements for perf/core:

. Overhaul the tools/ makefiles, gluing them to the top level Makefile, from
  Borislav Petkov.

. Move the UI files from tools/perf/util/ui/ to tools/perf/ui/. Also move
  the GTK+ browser to tools/perf/ui/gtk/, from Namhyung Kim.

. Only fallback to sw cycles counter on ENOENT for the hw cycles, from
  Robert Richter

. Trivial fixes from Robert Richter

. Handle the autogenerated bison/flex files better, from Namhyung and Jiri Olsa.

. Navigate jump instructions in the annotate browser, just press enter or ->,
  still needs support for a jump navigation history, i.e. to go back.

. Search string in the annotate browser: same keys as vim:
     / forward
     n next backward/forward
     ? backward

. Clarify number of events/samples in the report header, from Ashay Rane

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 16 insertions, 15 deletions

diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index 78b519c1353..e159e682ad4 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -1,4 +1,4 @@
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/fs.h>
 #include <linux/path.h>
@@ -26,11 +26,11 @@ void set_fs_root(struct fs_struct *fs, struct path *path)
 {
 	struct path old_root;
 
+	path_get_longterm(path);
 	spin_lock(&fs->lock);
 	write_seqcount_begin(&fs->seq);
 	old_root = fs->root;
 	fs->root = *path;
-	path_get_longterm(path);
 	write_seqcount_end(&fs->seq);
 	spin_unlock(&fs->lock);
 	if (old_root.dentry)
@@ -45,11 +45,11 @@ void set_fs_pwd(struct fs_struct *fs, struct path *path)
 {
 	struct path old_pwd;
 
+	path_get_longterm(path);
 	spin_lock(&fs->lock);
 	write_seqcount_begin(&fs->seq);
 	old_pwd = fs->pwd;
 	fs->pwd = *path;
-	path_get_longterm(path);
 	write_seqcount_end(&fs->seq);
 	spin_unlock(&fs->lock);
 
@@ -57,6 +57,14 @@ void set_fs_pwd(struct fs_struct *fs, struct path *path)
 		path_put_longterm(&old_pwd);
 }
 
+static inline int replace_path(struct path *p, const struct path *old, const struct path *new)
+{
+	if (likely(p->dentry != old->dentry || p->mnt != old->mnt))
+		return 0;
+	*p = *new;
+	return 1;
+}
+
 void chroot_fs_refs(struct path *old_root, struct path *new_root)
 {
 	struct task_struct *g, *p;
@@ -68,21 +76,16 @@ void chroot_fs_refs(struct path *old_root, struct path *new_root)
 		task_lock(p);
 		fs = p->fs;
 		if (fs) {
+			int hits = 0;
 			spin_lock(&fs->lock);
 			write_seqcount_begin(&fs->seq);
-			if (fs->root.dentry == old_root->dentry
-			    && fs->root.mnt == old_root->mnt) {
-				path_get_longterm(new_root);
-				fs->root = *new_root;
+			hits += replace_path(&fs->root, old_root, new_root);
+			hits += replace_path(&fs->pwd, old_root, new_root);
+			write_seqcount_end(&fs->seq);
+			while (hits--) {
 				count++;
-			}
-			if (fs->pwd.dentry == old_root->dentry
-			    && fs->pwd.mnt == old_root->mnt) {
 				path_get_longterm(new_root);
-				fs->pwd = *new_root;
-				count++;
 			}
-			write_seqcount_end(&fs->seq);
 			spin_unlock(&fs->lock);
 		}
 		task_unlock(p);
@@ -107,10 +110,8 @@ void exit_fs(struct task_struct *tsk)
 		int kill;
 		task_lock(tsk);
 		spin_lock(&fs->lock);
-		write_seqcount_begin(&fs->seq);
 		tsk->fs = NULL;
 		kill = !--fs->users;
-		write_seqcount_end(&fs->seq);
 		spin_unlock(&fs->lock);
 		task_unlock(tsk);
 		if (kill)