Re: [PATCH, RFC] xfs: remove i_iolock and use i_rwsem in the VFS inode instead

[Christoph Hellwig <hch@xxxxxx>]

Peter, this is the fixed up patch.  Can you write a proper changelog
and add your signoff?

---
 include/linux/lockdep.h  | 18 ++++++++++++++++--
 kernel/locking/lockdep.c | 43 ++++++++++++++++++++++++++-----------------
 2 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index eabe013..4cef9f8 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -338,9 +338,15 @@ extern void lock_acquire(struct lockdep_map *lock, 
unsigned int subclass,
 extern void lock_release(struct lockdep_map *lock, int nested,
                         unsigned long ip);
 
-#define lockdep_is_held(lock)  lock_is_held(&(lock)->dep_map)
+extern int _lock_is_held(struct lockdep_map *lock, int read);
 
-extern int lock_is_held(struct lockdep_map *lock);
+static inline int lock_is_held(struct lockdep_map *lock)
+{
+       return _lock_is_held(lock, -1);
+}
+
+#define lockdep_is_held(lock)          lock_is_held(&(lock)->dep_map)
+#define _lockdep_is_held(lock, r)      _lock_is_held(&(lock)->dep_map, (r))
 
 extern void lock_set_class(struct lockdep_map *lock, const char *name,
                           struct lock_class_key *key, unsigned int subclass,
@@ -372,6 +378,14 @@ extern void lock_unpin_lock(struct lockdep_map *lock, 
struct pin_cookie);
                WARN_ON(debug_locks && !lockdep_is_held(l));    \
        } while (0)
 
+#define lockdep_assert_held_exclusive(l)       do {            \
+               WARN_ON(debug_locks && !_lockdep_is_held(l, 0));\
+       } while (0)
+
+#define lockdep_assert_held_read(l)    do {                    \
+               WARN_ON(debug_locks && !_lockdep_is_held(l, 1));\
+       } while (0)
+
 #define lockdep_assert_held_once(l)    do {                            \
                WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));       \
        } while (0)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 589d763..f39573b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3188,7 +3188,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr,
        return 0;
 }
 
-static int __lock_is_held(struct lockdep_map *lock);
+static int __lock_is_held(struct lockdep_map *lock, int read);
 
 /*
  * This gets called for every mutex_lock*()/spin_lock*() operation.
@@ -3329,7 +3329,7 @@ static int __lock_acquire(struct lockdep_map *lock, 
unsigned int subclass,
        }
        chain_key = iterate_chain_key(chain_key, class_idx);
 
-       if (nest_lock && !__lock_is_held(nest_lock))
+       if (nest_lock && !__lock_is_held(nest_lock, -1))
                return print_lock_nested_lock_not_held(curr, hlock, ip);
 
        if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
@@ -3390,10 +3390,17 @@ print_unlock_imbalance_bug(struct task_struct *curr, 
struct lockdep_map *lock,
        return 0;
 }
 
-static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
+static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock, 
int read)
 {
-       if (hlock->instance == lock)
-               return 1;
+       if (hlock->instance == lock) {
+               if (read == -1)
+                       return 1;
+
+               if (hlock->read == read)
+                       return 1;
+
+               return 0;
+       }
 
        if (hlock->references) {
                struct lock_class *class = lock->class_cache[0];
@@ -3420,6 +3427,8 @@ static int match_held_lock(struct held_lock *hlock, 
struct lockdep_map *lock)
 
                if (hlock->class_idx == class - lock_classes + 1)
                        return 1;
+
+               /* XXX do we want @read stuff for nested locks !? */
        }
 
        return 0;
@@ -3452,7 +3461,7 @@ __lock_set_class(struct lockdep_map *lock, const char 
*name,
                 */
                if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
                        break;
-               if (match_held_lock(hlock, lock))
+               if (match_held_lock(hlock, lock, -1))
                        goto found_it;
                prev_hlock = hlock;
        }
@@ -3523,7 +3532,7 @@ __lock_release(struct lockdep_map *lock, int nested, 
unsigned long ip)
                 */
                if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
                        break;
-               if (match_held_lock(hlock, lock))
+               if (match_held_lock(hlock, lock, -1))
                        goto found_it;
                prev_hlock = hlock;
        }
@@ -3576,7 +3585,7 @@ found_it:
        return 1;
 }
 
-static int __lock_is_held(struct lockdep_map *lock)
+static int __lock_is_held(struct lockdep_map *lock, int read)
 {
        struct task_struct *curr = current;
        int i;
@@ -3584,7 +3593,7 @@ static int __lock_is_held(struct lockdep_map *lock)
        for (i = 0; i < curr->lockdep_depth; i++) {
                struct held_lock *hlock = curr->held_locks + i;
 
-               if (match_held_lock(hlock, lock))
+               if (match_held_lock(hlock, lock, read))
                        return 1;
        }
 
@@ -3603,7 +3612,7 @@ static struct pin_cookie __lock_pin_lock(struct 
lockdep_map *lock)
        for (i = 0; i < curr->lockdep_depth; i++) {
                struct held_lock *hlock = curr->held_locks + i;
 
-               if (match_held_lock(hlock, lock)) {
+               if (match_held_lock(hlock, lock, -1)) {
                        /*
                         * Grab 16bits of randomness; this is sufficient to not
                         * be guessable and still allows some pin nesting in
@@ -3630,7 +3639,7 @@ static void __lock_repin_lock(struct lockdep_map *lock, 
struct pin_cookie cookie
        for (i = 0; i < curr->lockdep_depth; i++) {
                struct held_lock *hlock = curr->held_locks + i;
 
-               if (match_held_lock(hlock, lock)) {
+               if (match_held_lock(hlock, lock, -1)) {
                        hlock->pin_count += cookie.val;
                        return;
                }
@@ -3650,7 +3659,7 @@ static void __lock_unpin_lock(struct lockdep_map *lock, 
struct pin_cookie cookie
        for (i = 0; i < curr->lockdep_depth; i++) {
                struct held_lock *hlock = curr->held_locks + i;
 
-               if (match_held_lock(hlock, lock)) {
+               if (match_held_lock(hlock, lock, -1)) {
                        if (WARN(!hlock->pin_count, "unpinning an unpinned 
lock\n"))
                                return;
 
@@ -3769,7 +3778,7 @@ void lock_release(struct lockdep_map *lock, int nested,
 }
 EXPORT_SYMBOL_GPL(lock_release);
 
-int lock_is_held(struct lockdep_map *lock)
+int _lock_is_held(struct lockdep_map *lock, int read)
 {
        unsigned long flags;
        int ret = 0;
@@ -3781,13 +3790,13 @@ int lock_is_held(struct lockdep_map *lock)
        check_flags(flags);
 
        current->lockdep_recursion = 1;
-       ret = __lock_is_held(lock);
+       ret = __lock_is_held(lock, read);
        current->lockdep_recursion = 0;
        raw_local_irq_restore(flags);
 
        return ret;
 }
-EXPORT_SYMBOL_GPL(lock_is_held);
+EXPORT_SYMBOL_GPL(_lock_is_held);
 
 struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
 {
@@ -3908,7 +3917,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long 
ip)
                 */
                if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
                        break;
-               if (match_held_lock(hlock, lock))
+               if (match_held_lock(hlock, lock, -1))
                        goto found_it;
                prev_hlock = hlock;
        }
@@ -3961,7 +3970,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long 
ip)
                 */
                if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
                        break;
-               if (match_held_lock(hlock, lock))
+               if (match_held_lock(hlock, lock, -1))
                        goto found_it;
                prev_hlock = hlock;
        }
-- 
2.1.4