ext4: avoid kmemcheck complaint from reading uninitialized memory

[linux-2.6.git] / fs / ioprio.c

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 10d2c211d18b28414aa8b0f26dcfe489fa0ddfe9..0f1b9515213b14e5f4c2e8606efea4ff1a8c2fc4 100644 (file)
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -19,42 +19,46 @@
  * 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>
 #include <linux/syscalls.h>
 #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);
-
-       task->ioprio = ioprio;
-
-       ioc = task->io_context;
-       /* see wmb() in current_io_context() */
-       smp_read_barrier_depends();
-
-       if (ioc)
-               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 0;
+       return err;
 }
+EXPORT_SYMBOL_GPL(set_task_ioprio);
 
-asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
+SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
 {
        int class = IOPRIO_PRIO_CLASS(ioprio);
        int data = IOPRIO_PRIO_DATA(ioprio);
@@ -74,26 +78,23 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
 
                        break;
                case IOPRIO_CLASS_IDLE:
-                       if (!capable(CAP_SYS_ADMIN))
-                               return -EPERM;
+                       break;
+               case IOPRIO_CLASS_NONE:
+                       if (data)
+                               return -EINVAL;
                        break;
                default:
                        return -EINVAL;
        }
 
        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)
                                p = current;
                        else
-                               p = find_task_by_pid(who);
+                               p = find_task_by_vpid(who);
                        if (p)
                                ret = set_task_ioprio(p, ioprio);
                        break;
@@ -101,16 +102,16 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
                        if (!who)
                                pgrp = task_pgrp(current);
                        else
-                               pgrp = find_pid(who);
-                       do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+                               pgrp = find_vpid(who);
+                       do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
                                ret = set_task_ioprio(p, ioprio);
                                if (ret)
                                        break;
-                       } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+                       } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                        break;
                case IOPRIO_WHO_USER:
                        if (!who)
-                               user = current->user;
+                               user = current_user();
                        else
                                user = find_user(who);
 
@@ -118,7 +119,7 @@ asmlinkage long sys_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)
@@ -132,7 +133,7 @@ free_uid:
                        ret = -EINVAL;
        }
 
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }
 
@@ -143,7 +144,9 @@ static int get_task_ioprio(struct task_struct *p)
        ret = security_task_getioprio(p);
        if (ret)
                goto out;
-       ret = p->ioprio;
+       ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
+       if (p->io_context)
+               ret = p->io_context->ioprio;
 out:
        return ret;
 }
@@ -166,7 +169,7 @@ int ioprio_best(unsigned short aprio, unsigned short bprio)
                return aprio;
 }
 
-asmlinkage long sys_ioprio_get(int which, int who)
+SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
 {
        struct task_struct *g, *p;
        struct user_struct *user;
@@ -174,13 +177,13 @@ asmlinkage long sys_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)
                                p = current;
                        else
-                               p = find_task_by_pid(who);
+                               p = find_task_by_vpid(who);
                        if (p)
                                ret = get_task_ioprio(p);
                        break;
@@ -188,8 +191,8 @@ asmlinkage long sys_ioprio_get(int which, int who)
                        if (!who)
                                pgrp = task_pgrp(current);
                        else
-                               pgrp = find_pid(who);
-                       do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+                               pgrp = find_vpid(who);
+                       do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
                                tmpio = get_task_ioprio(p);
                                if (tmpio < 0)
                                        continue;
@@ -197,11 +200,11 @@ asmlinkage long sys_ioprio_get(int which, int who)
                                        ret = tmpio;
                                else
                                        ret = ioprio_best(ret, tmpio);
-                       } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+                       } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                        break;
                case IOPRIO_WHO_USER:
                        if (!who)
-                               user = current->user;
+                               user = current_user();
                        else
                                user = find_user(who);
 
@@ -209,7 +212,7 @@ asmlinkage long sys_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)
@@ -227,7 +230,6 @@ asmlinkage long sys_ioprio_get(int which, int who)
                        ret = -EINVAL;
        }
 
-       read_unlock(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }
-