Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
[linux-2.6.git] / fs / ioprio.c
index e4e01bc..c7c0b28 100644 (file)
 #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;
 
-       task->ioprio = ioprio;
-
-       ioc = task->io_context;
-       /* see wmb() in current_io_context() */
-       smp_read_barrier_depends();
+               ioc = alloc_io_context(GFP_ATOMIC, -1);
+               if (!ioc) {
+                       err = -ENOMEM;
+                       break;
+               }
+               task->io_context = ioc;
+       } while (1);
 
-       if (ioc)
+       if (!err) {
+               ioc->ioprio = ioprio;
                ioc->ioprio_changed = 1;
+       }
 
        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);
@@ -75,8 +92,6 @@ 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)
@@ -107,15 +122,15 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
                                pgrp = task_pgrp(current);
                        else
                                pgrp = find_vpid(who);
-                       do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+                       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);
 
@@ -123,7 +138,7 @@ 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)
@@ -148,7 +163,9 @@ 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;
 }
@@ -171,7 +188,7 @@ 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;
@@ -194,7 +211,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
                                pgrp = task_pgrp(current);
                        else
                                pgrp = find_vpid(who);
-                       do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+                       do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
                                tmpio = get_task_ioprio(p);
                                if (tmpio < 0)
                                        continue;
@@ -202,11 +219,11 @@ 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);
 
@@ -214,7 +231,7 @@ 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)
@@ -235,4 +252,3 @@ asmlinkage long sys_ioprio_get(int which, int who)
        read_unlock(&tasklist_lock);
        return ret;
 }
-