Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cciss: fix build for PROC_FS disabled
  block: fix amiga and atari floppy driver compile warning
  blk-throttle: Fix calculation of max number of WRITES to be dispatched
  ioprio: grab rcu_read_lock in sys_ioprio_{set,get}()
  xen/blkfront: cope with backend that fail empty BLKIF_OP_WRITE_BARRIER requests
  xen/blkfront: Implement FUA with BLKIF_OP_WRITE_BARRIER
  xen/blkfront: change blk_shadow.request to proper pointer
  xen/blkfront: map REQ_FLUSH into a full barrier

1 files changed, 6 insertions, 25 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 2f7d05c89922..7da2a06508e5 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -103,22 +103,15 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
         }
 
         ret = -ESRCH;
-        /*
-         * We want IOPRIO_WHO_PGRP/IOPRIO_WHO_USER to be "atomic",
-         * so we can't use rcu_read_lock(). See re-copy of ->ioprio
-         * in copy_process().
-         */
-        read_lock(&tasklist_lock);
+        rcu_read_lock();
         switch (which) {
                 case IOPRIO_WHO_PROCESS:
-                        rcu_read_lock();
                         if (!who)
                                 p = current;
                         else
                                 p = find_task_by_vpid(who);
                         if (p)
                                 ret = set_task_ioprio(p, ioprio);
-                        rcu_read_unlock();
                         break;
                 case IOPRIO_WHO_PGRP:
                         if (!who)
@@ -141,12 +134,7 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
                                 break;
 
                         do_each_thread(g, p) {
-                                int match;
-
-                                rcu_read_lock();
-                                match = __task_cred(p)->uid == who;
-                                rcu_read_unlock();
-                                if (!match)
+                                if (__task_cred(p)->uid != who)
                                         continue;
                                 ret = set_task_ioprio(p, ioprio);
                                 if (ret)
@@ -160,7 +148,7 @@ free_uid:
                         ret = -EINVAL;
         }
 
-        read_unlock(&tasklist_lock);
+        rcu_read_unlock();
         return ret;
 }
 
@@ -204,17 +192,15 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
         int ret = -ESRCH;
         int tmpio;
 
-        read_lock(&tasklist_lock);
+        rcu_read_lock();
         switch (which) {
                 case IOPRIO_WHO_PROCESS:
-                        rcu_read_lock();
                         if (!who)
                                 p = current;
                         else
                                 p = find_task_by_vpid(who);
                         if (p)
                                 ret = get_task_ioprio(p);
-                        rcu_read_unlock();
                         break;
                 case IOPRIO_WHO_PGRP:
                         if (!who)
@@ -241,12 +227,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                                 break;
 
                         do_each_thread(g, p) {
-                                int match;
-
-                                rcu_read_lock();
-                                match = __task_cred(p)->uid == user->uid;
-                                rcu_read_unlock();
-                                if (!match)
+                                if (__task_cred(p)->uid != user->uid)
                                         continue;
                                 tmpio = get_task_ioprio(p);
                                 if (tmpio < 0)
@@ -264,6 +245,6 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                         ret = -EINVAL;
         }
 
-        read_unlock(&tasklist_lock);
+        rcu_read_unlock();
         return ret;
 }