staging: lustre: fix sparse warnings related to lock context imbalance

Applies against next-20150120.

Add __acquires() and __releases() function annotations, to fix sparse warnings related to lock context imbalance.

This patch fixes the following warnings:

drivers/staging/lustre//lustre/libcfs/linux/linux-tracefile.c:153:5: warning: context imbalance in 'cfs_trace_lock_tcd' - wrong count at exit
drivers/staging/lustre//lustre/libcfs/linux/linux-tracefile.c:171:39: warning: context imbalance in 'cfs_trace_unlock_tcd' - unexpected unlock
drivers/staging/lustre//lustre/libcfs/hash.c:128:1: warning: context imbalance in 'cfs_hash_spin_lock' - wrong count at exit
drivers/staging/lustre//lustre/libcfs/hash.c:134:1: warning: context imbalance in 'cfs_hash_spin_unlock' - unexpected unlock
drivers/staging/lustre//lustre/libcfs/hash.c:142:9: warning: context imbalance in 'cfs_hash_rw_lock' - wrong count at exit
include/linux/rwlock_api_smp.h:219:9: warning: context imbalance in 'cfs_hash_rw_unlock' - unexpected unlock
drivers/staging/lustre//lustre/obdclass/cl_object.c:195:6: warning: context imbalance in 'cl_object_attr_lock' - wrong count at exit
drivers/staging/lustre//lustre/obdclass/cl_object.c:204:6: warning: context imbalance in 'cl_object_attr_unlock' - unexpected unlock
Signed-off-by: Loic Pefferkorn <loic@loicp.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/libcfs/hash.c

@@ -126,18 +126,21 @@ cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {}
 
 static inline void
 cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive)
+	__acquires(&lock->spin)
 {
 	spin_lock(&lock->spin);
 }
 
 static inline void
 cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive)
+	__releases(&lock->spin)
 {
 	spin_unlock(&lock->spin);
 }
 
 static inline void
 cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive)
+	__acquires(&lock->rw)
 {
 	if (!exclusive)
 		read_lock(&lock->rw);
@@ -147,6 +150,7 @@ cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive)
 
 static inline void
 cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive)
+	__releases(&lock->rw)
 {
 	if (!exclusive)
 		read_unlock(&lock->rw);

drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c

@@ -151,6 +151,7 @@ cfs_trace_buf_type_t cfs_trace_buf_idx_get(void)
  * for details.
  */
 int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+	__acquires(&tcd->tc_lock)
 {
 	__LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX);
 	if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)
@@ -165,6 +166,7 @@ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
 }
 
 void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+	__releases(&tcd->tcd_lock)
 {
 	__LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX);
 	if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)

drivers/staging/lustre/lustre/obdclass/cl_object.c

@@ -193,6 +193,7 @@ static spinlock_t *cl_object_attr_guard(struct cl_object *o)
  * cl_object_attr_get(), cl_object_attr_set().
  */
 void cl_object_attr_lock(struct cl_object *o)
+	__acquires(cl_object_attr_guard(o))
 {
 	spin_lock(cl_object_attr_guard(o));
 }
@@ -202,6 +203,7 @@ EXPORT_SYMBOL(cl_object_attr_lock);
  * Releases data-attributes lock, acquired by cl_object_attr_lock().
  */
 void cl_object_attr_unlock(struct cl_object *o)
+	__releases(cl_object_attr_guard(o))
 {
 	spin_unlock(cl_object_attr_guard(o));
 }