Merge branch 'poll' into staging/for_v3.4

* poll: (5970 commits)
  poll: add poll_requested_events() and poll_does_not_wait() functions
  crc32: select an algorithm via Kconfig
  crc32: add self-test code for crc32c
  crypto: crc32c should use library implementation
  crc32: bolt on crc32c
  crc32: add note about this patchset to crc32.c
  crc32: optimize loop counter for x86
  crc32: add slice-by-8 algorithm to existing code
  crc32: make CRC_*_BITS definition correspond to actual bit counts
  crc32: fix mixing of endian-specific types
  crc32: miscellaneous cleanups
  crc32: simplify unit test code
  crc32: move long comment about crc32 fundamentals to Documentation/
  crc32: remove two instances of trailing whitespaces
  checkpatch: check for quoted strings broken across lines
  checkpatch: whitespace - add/remove blank lines
  checkpatch: warn on use of yield()
  checkpatch: add --strict tests for braces, comments and casts
  checkpatch: add [] to type extensions
  checkpatch: high precedence operators do not require additional parentheses in #defines
  ...

1 files changed, 15 insertions, 14 deletions

diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index 78b519c13536..6324c4274959 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -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)