Update to 3.4-final.

[linux-flexiantxendom0-3.2.10.git] / fs / ioprio.c

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 3715d7d..0f1b951 100644 (file)
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -19,7 +19,9 @@
  * See also Documentation/block/ioprio.txt
  *
  */
+#include <linux/gfp.h>
 #include <linux/kernel.h>
+#include <linux/export.h>
 #include <linux/ioprio.h>
 #include <linux/blkdev.h>
 #include <linux/capability.h>
@@ -27,43 +29,34 @@
 #include <linux/security.h>
 #include <linux/pid_namespace.h>
 
-static int set_task_ioprio(struct task_struct *task, int ioprio)
+int set_task_ioprio(struct task_struct *task, int ioprio)
 {
        int err;
        struct io_context *ioc;
+       const struct cred *cred = current_cred(), *tcred;
 
-       if (task->uid != current->euid &&
-           task->uid != current->uid && !capable(CAP_SYS_NICE))
+       rcu_read_lock();
+       tcred = __task_cred(task);
+       if (tcred->uid != cred->euid &&
+           tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) {
+               rcu_read_unlock();
                return -EPERM;
+       }
+       rcu_read_unlock();
 
        err = security_task_setioprio(task, ioprio);
        if (err)
                return err;
 
-       task_lock(task);
-       do {
-               ioc = task->io_context;
-               /* see wmb() in current_io_context() */
-               smp_read_barrier_depends();
-               if (ioc)
-                       break;
-
-               ioc = alloc_io_context(GFP_ATOMIC, -1);
-               if (!ioc) {
-                       err = -ENOMEM;
-                       break;
-               }
-               task->io_context = ioc;
-       } while (1);
-
-       if (!err) {
-               ioc->ioprio = ioprio;
-               ioc->ioprio_changed = 1;
+       ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
+       if (ioc) {
+               ioc_ioprio_changed(ioc, ioprio);
+               put_io_context(ioc);
        }
 
-       task_unlock(task);
        return err;
 }
+EXPORT_SYMBOL_GPL(set_task_ioprio);
 
 SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
 {
@@ -95,12 +88,7 @@ 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:
                        if (!who)
@@ -123,7 +111,7 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
                        break;
                case IOPRIO_WHO_USER:
                        if (!who)
-                               user = current->user;
+                               user = current_user();
                        else
                                user = find_user(who);
 
@@ -131,7 +119,7 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
                                break;
 
                        do_each_thread(g, p) {
-                               if (p->uid != who)
+                               if (__task_cred(p)->uid != who)
                                        continue;
                                ret = set_task_ioprio(p, ioprio);
                                if (ret)
@@ -145,7 +133,7 @@ free_uid:
                        ret = -EINVAL;
        }
 
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }
 
@@ -189,7 +177,7 @@ 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:
                        if (!who)
@@ -216,7 +204,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                        break;
                case IOPRIO_WHO_USER:
                        if (!who)
-                               user = current->user;
+                               user = current_user();
                        else
                                user = find_user(who);
 
@@ -224,7 +212,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                                break;
 
                        do_each_thread(g, p) {
-                               if (p->uid != user->uid)
+                               if (__task_cred(p)->uid != user->uid)
                                        continue;
                                tmpio = get_task_ioprio(p);
                                if (tmpio < 0)
@@ -242,6 +230,6 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
                        ret = -EINVAL;
        }
 
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }