Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "The main RCU changes in this cycle were:

   - Updates to use cond_resched() instead of cond_resched_rcu_qs()
     where feasible (currently everywhere except in kernel/rcu and in
     kernel/torture.c). Also a couple of fixes to avoid sending IPIs to
     offline CPUs.

   - Updates to simplify RCU's dyntick-idle handling.

   - Updates to remove almost all uses of smp_read_barrier_depends() and
     read_barrier_depends().

   - Torture-test updates.

   - Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  torture: Save a line in stutter_wait(): while -> for
  torture: Eliminate torture_runnable and perf_runnable
  torture: Make stutter less vulnerable to compilers and races
  locking/locktorture: Fix num reader/writer corner cases
  locking/locktorture: Fix rwsem reader_delay
  torture: Place all torture-test modules in one MAINTAINERS group
  rcutorture/kvm-build.sh: Skip build directory check
  rcutorture: Simplify functions.sh include path
  rcutorture: Simplify logging
  rcutorture/kvm-recheck-*: Improve result directory readability check
  rcutorture/kvm.sh: Support execution from any directory
  rcutorture/kvm.sh: Use consistent help text for --qemu-args
  rcutorture/kvm.sh: Remove unused variable, `alldone`
  rcutorture: Remove unused script, config2frag.sh
  rcutorture/configinit: Fix build directory error message
  rcutorture: Preempt RCU-preempt readers more vigorously
  torture: Reduce #ifdefs for preempt_schedule()
  rcu: Remove have_rcu_nocb_mask from tree_plugin.h
  rcu: Add comment giving debug strategy for double call_rcu()
  tracing, rcu: Hide trace event rcu_nocb_wake when not used
  ...

2 files changed, 4 insertions, 8 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 5c7df1df81ff..379dce86f001 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1636,8 +1636,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 	dname[name->len] = 0;
 
 	/* Make sure we always see the terminating NUL character */
-	smp_wmb();
-	dentry->d_name.name = dname;
+	smp_store_release(&dentry->d_name.name, dname); /* ^^^ */
 
 	dentry->d_lockref.count = 1;
 	dentry->d_flags = 0;
@@ -3047,17 +3046,14 @@ static int prepend(char **buffer, int *buflen, const char *str, int namelen)
  * retry it again when a d_move() does happen. So any garbage in the buffer
  * due to mismatched pointer and length will be discarded.
  *
- * Data dependency barrier is needed to make sure that we see that terminating
- * NUL.  Alpha strikes again, film at 11...
+ * Load acquire is needed to make sure that we see that terminating NUL.
  */
 static int prepend_name(char **buffer, int *buflen, const struct qstr *name)
 {
-	const char *dname = READ_ONCE(name->name);
+	const char *dname = smp_load_acquire(&name->name); /* ^^^ */
 	u32 dlen = READ_ONCE(name->len);
 	char *p;
 
-	smp_read_barrier_depends();
-
 	*buflen -= dlen + 1;
 	if (*buflen < 0)
 		return -ENAMETOOLONG;
diff --git a/fs/file.c b/fs/file.c
index 3b080834b870..fc0eeb812e2c 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -391,7 +391,7 @@ static struct fdtable *close_files(struct files_struct * files)
 				struct file * file = xchg(&fdt->fd[i], NULL);
 				if (file) {
 					filp_close(file, files);
-					cond_resched_rcu_qs();
+					cond_resched();
 				}
 			}
 			i++;