1 files changed, 19 insertions, 37 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 1c9c5f0a9e2b..8216aa0c7539 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -554,8 +554,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
         struct aio_ring *ring;
 
         spin_lock(&mm->ioctx_lock);
-        rcu_read_lock();
-        table = rcu_dereference(mm->ioctx_table);
+        table = rcu_dereference_raw(mm->ioctx_table);
 
         while (1) {
                 if (table)
@@ -563,7 +562,6 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
                                 if (!table->table[i]) {
                                         ctx->id = i;
                                         table->table[i] = ctx;
-                                        rcu_read_unlock();
                                         spin_unlock(&mm->ioctx_lock);
 
                                         /* While kioctx setup is in progress,
@@ -577,8 +575,6 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
                                 }
 
                 new_nr = (table ? table->nr : 1) * 4;
-
-                rcu_read_unlock();
                 spin_unlock(&mm->ioctx_lock);
 
                 table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
@@ -589,8 +585,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
                 table->nr = new_nr;
 
                 spin_lock(&mm->ioctx_lock);
-                rcu_read_lock();
-                old = rcu_dereference(mm->ioctx_table);
+                old = rcu_dereference_raw(mm->ioctx_table);
 
                 if (!old) {
                         rcu_assign_pointer(mm->ioctx_table, table);
@@ -737,12 +732,9 @@ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
 
 
         spin_lock(&mm->ioctx_lock);
-        rcu_read_lock();
-        table = rcu_dereference(mm->ioctx_table);
-
+        table = rcu_dereference_raw(mm->ioctx_table);
         WARN_ON(ctx != table->table[ctx->id]);
         table->table[ctx->id] = NULL;
-        rcu_read_unlock();
         spin_unlock(&mm->ioctx_lock);
 
         /* percpu_ref_kill() will do the necessary call_rcu() */
@@ -791,40 +783,30 @@ EXPORT_SYMBOL(wait_on_sync_kiocb);
  */
 void exit_aio(struct mm_struct *mm)
 {
-        struct kioctx_table *table;
-        struct kioctx *ctx;
-        unsigned i = 0;
-
-        while (1) {
-                rcu_read_lock();
-                table = rcu_dereference(mm->ioctx_table);
-
-                do {
-                        if (!table || i >= table->nr) {
-                                rcu_read_unlock();
-                                rcu_assign_pointer(mm->ioctx_table, NULL);
-                                if (table)
-                                        kfree(table);
-                                return;
-                        }
+        struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
+        int i;
 
-                        ctx = table->table[i++];
-                } while (!ctx);
+        if (!table)
+                return;
 
-                rcu_read_unlock();
+        for (i = 0; i < table->nr; ++i) {
+                struct kioctx *ctx = table->table[i];
 
+                if (!ctx)
+                        continue;
                 /*
-                 * We don't need to bother with munmap() here -
-                 * exit_mmap(mm) is coming and it'll unmap everything.
-                 * Since aio_free_ring() uses non-zero ->mmap_size
-                 * as indicator that it needs to unmap the area,
-                 * just set it to 0; aio_free_ring() is the only
-                 * place that uses ->mmap_size, so it's safe.
+                 * We don't need to bother with munmap() here - exit_mmap(mm)
+                 * is coming and it'll unmap everything. And we simply can't,
+                 * this is not necessarily our ->mm.
+                 * Since kill_ioctx() uses non-zero ->mmap_size as indicator
+                 * that it needs to unmap the area, just set it to 0.
                  */
                 ctx->mmap_size = 0;
-
                 kill_ioctx(mm, ctx, NULL);
         }
+
+        RCU_INIT_POINTER(mm->ioctx_table, NULL);
+        kfree(table);
 }
 
 static void put_reqs_available(struct kioctx *ctx, unsigned nr)