ipc: rename ids->rw_mutex

Since in some situations the lock can be shared for readers, we shouldn't
be calling it a mutex, rename it to rwsem.

Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 28 insertions, 28 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 28d19f4ece4b..cb2cedaa8808 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -83,8 +83,8 @@ void shm_init_ns(struct ipc_namespace *ns)
 }
 
 /*
- * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
- * Only shm_ids.rw_mutex remains locked on exit.
+ * Called with shm_ids.rwsem (writer) and the shp structure locked.
+ * Only shm_ids.rwsem remains locked on exit.
  */
 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 {
@@ -148,7 +148,7 @@ static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace
 }
 
 /*
- * shm_lock_(check_) routines are called in the paths where the rw_mutex
+ * shm_lock_(check_) routines are called in the paths where the rwsem
  * is not necessarily held.
  */
 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
@@ -205,7 +205,7 @@ static void shm_open(struct vm_area_struct *vma)
  * @ns: namespace
  * @shp: struct to free
  *
- * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
+ * It has to be called with shp and shm_ids.rwsem (writer) locked,
  * but returns with shp unlocked and freed.
  */
 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
@@ -253,7 +253,7 @@ static void shm_close(struct vm_area_struct *vma)
         struct shmid_kernel *shp;
         struct ipc_namespace *ns = sfd->ns;
 
-        down_write(&shm_ids(ns).rw_mutex);
+        down_write(&shm_ids(ns).rwsem);
         /* remove from the list of attaches of the shm segment */
         shp = shm_lock(ns, sfd->id);
         BUG_ON(IS_ERR(shp));
@@ -264,10 +264,10 @@ static void shm_close(struct vm_area_struct *vma)
                 shm_destroy(ns, shp);
         else
                 shm_unlock(shp);
-        up_write(&shm_ids(ns).rw_mutex);
+        up_write(&shm_ids(ns).rwsem);
 }
 
-/* Called with ns->shm_ids(ns).rw_mutex locked */
+/* Called with ns->shm_ids(ns).rwsem locked */
 static int shm_try_destroy_current(int id, void *p, void *data)
 {
         struct ipc_namespace *ns = data;
@@ -298,7 +298,7 @@ static int shm_try_destroy_current(int id, void *p, void *data)
         return 0;
 }
 
-/* Called with ns->shm_ids(ns).rw_mutex locked */
+/* Called with ns->shm_ids(ns).rwsem locked */
 static int shm_try_destroy_orphaned(int id, void *p, void *data)
 {
         struct ipc_namespace *ns = data;
@@ -309,7 +309,7 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data)
          * We want to destroy segments without users and with already
          * exit'ed originating process.
          *
-         * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
+         * As shp->* are changed under rwsem, it's safe to skip shp locking.
          */
         if (shp->shm_creator != NULL)
                 return 0;
@@ -323,10 +323,10 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data)
 
 void shm_destroy_orphaned(struct ipc_namespace *ns)
 {
-        down_write(&shm_ids(ns).rw_mutex);
+        down_write(&shm_ids(ns).rwsem);
         if (shm_ids(ns).in_use)
                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
-        up_write(&shm_ids(ns).rw_mutex);
+        up_write(&shm_ids(ns).rwsem);
 }
 
 
@@ -338,10 +338,10 @@ void exit_shm(struct task_struct *task)
                 return;
 
         /* Destroy all already created segments, but not mapped yet */
-        down_write(&shm_ids(ns).rw_mutex);
+        down_write(&shm_ids(ns).rwsem);
         if (shm_ids(ns).in_use)
                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
-        up_write(&shm_ids(ns).rw_mutex);
+        up_write(&shm_ids(ns).rwsem);
 }
 
 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -475,7 +475,7 @@ static const struct vm_operations_struct shm_vm_ops = {
  * @ns: namespace
  * @params: ptr to the structure that contains key, size and shmflg
  *
- * Called with shm_ids.rw_mutex held as a writer.
+ * Called with shm_ids.rwsem held as a writer.
  */
 
 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
@@ -583,7 +583,7 @@ no_file:
 }
 
 /*
- * Called with shm_ids.rw_mutex and ipcp locked.
+ * Called with shm_ids.rwsem and ipcp locked.
  */
 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 {
@@ -594,7 +594,7 @@ static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 }
 
 /*
- * Called with shm_ids.rw_mutex and ipcp locked.
+ * Called with shm_ids.rwsem and ipcp locked.
  */
 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
                                 struct ipc_params *params)
@@ -707,7 +707,7 @@ static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminf
 
 /*
  * Calculate and add used RSS and swap pages of a shm.
- * Called with shm_ids.rw_mutex held as a reader
+ * Called with shm_ids.rwsem held as a reader
  */
 static void shm_add_rss_swap(struct shmid_kernel *shp,
         unsigned long *rss_add, unsigned long *swp_add)
@@ -734,7 +734,7 @@ static void shm_add_rss_swap(struct shmid_kernel *shp,
 }
 
 /*
- * Called with shm_ids.rw_mutex held as a reader
+ * Called with shm_ids.rwsem held as a reader
  */
 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
                 unsigned long *swp)
@@ -763,9 +763,9 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 }
 
 /*
- * This function handles some shmctl commands which require the rw_mutex
+ * This function handles some shmctl commands which require the rwsem
  * to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
  */
 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
                        struct shmid_ds __user *buf, int version)
@@ -780,7 +780,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
                         return -EFAULT;
         }
 
-        down_write(&shm_ids(ns).rw_mutex);
+        down_write(&shm_ids(ns).rwsem);
         rcu_read_lock();
 
         ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
@@ -819,7 +819,7 @@ out_unlock0:
 out_unlock1:
         rcu_read_unlock();
 out_up:
-        up_write(&shm_ids(ns).rw_mutex);
+        up_write(&shm_ids(ns).rwsem);
         return err;
 }
 
@@ -850,9 +850,9 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
                 if(copy_shminfo_to_user (buf, &shminfo, version))
                         return -EFAULT;
 
-                down_read(&shm_ids(ns).rw_mutex);
+                down_read(&shm_ids(ns).rwsem);
                 err = ipc_get_maxid(&shm_ids(ns));
-                up_read(&shm_ids(ns).rw_mutex);
+                up_read(&shm_ids(ns).rwsem);
 
                 if(err<0)
                         err = 0;
@@ -863,14 +863,14 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
                 struct shm_info shm_info;
 
                 memset(&shm_info, 0, sizeof(shm_info));
-                down_read(&shm_ids(ns).rw_mutex);
+                down_read(&shm_ids(ns).rwsem);
                 shm_info.used_ids = shm_ids(ns).in_use;
                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
                 shm_info.shm_tot = ns->shm_tot;
                 shm_info.swap_attempts = 0;
                 shm_info.swap_successes = 0;
                 err = ipc_get_maxid(&shm_ids(ns));
-                up_read(&shm_ids(ns).rw_mutex);
+                up_read(&shm_ids(ns).rwsem);
                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
                         err = -EFAULT;
                         goto out;
@@ -1169,7 +1169,7 @@ out_fput:
         fput(file);
 
 out_nattch:
-        down_write(&shm_ids(ns).rw_mutex);
+        down_write(&shm_ids(ns).rwsem);
         shp = shm_lock(ns, shmid);
         BUG_ON(IS_ERR(shp));
         shp->shm_nattch--;
@@ -1177,7 +1177,7 @@ out_nattch:
                 shm_destroy(ns, shp);
         else
                 shm_unlock(shp);
-        up_write(&shm_ids(ns).rw_mutex);
+        up_write(&shm_ids(ns).rwsem);
         return err;
 
 out_unlock: