fat: Remove FAT Directory Bread message
[linux-2.6.git] / fs / ioprio.c
index 663e420..7da2a06 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * fs/ioprio.c
  *
- * Copyright (C) 2004 Jens Axboe <axboe@suse.de>
+ * Copyright (C) 2004 Jens Axboe <axboe@kernel.dk>
  *
  * Helper functions for setting/querying io priorities of processes. The
  * system calls closely mimmick getpriority/setpriority, see the man page for
  * See also Documentation/block/ioprio.txt
  *
  */
+#include <linux/gfp.h>
 #include <linux/kernel.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);
+       do {
+               ioc = task->io_context;
+               /* see wmb() in current_io_context() */
+               smp_read_barrier_depends();
+               if (ioc)
+                       break;
 
-       task->ioprio = ioprio;
+               ioc = alloc_io_context(GFP_ATOMIC, -1);
+               if (!ioc) {
+                       err = -ENOMEM;
+                       break;
+               }
+               task->io_context = ioc;
+       } while (1);
 
-       ioc = task->io_context;
-       if (ioc && ioc->set_ioprio)
-               ioc->set_ioprio(ioc, ioprio);
+       if (!err) {
+               ioc->ioprio = ioprio;
+               ioc->ioprio_changed = 1;
+       }
 
        task_unlock(task);
-       return 0;
+       return err;
 }
+EXPORT_SYMBOL_GPL(set_task_ioprio);
 
-asmlinkage int 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);
        struct task_struct *p, *g;
        struct user_struct *user;
+       struct pid *pgrp;
        int ret;
 
        switch (class) {
@@ -63,33 +94,39 @@ asmlinkage int sys_ioprio_set(int which, int who, int ioprio)
                        break;
                case IOPRIO_CLASS_IDLE:
                        break;
+               case IOPRIO_CLASS_NONE:
+                       if (data)
+                               return -EINVAL;
+                       break;
                default:
                        return -EINVAL;
        }
 
        ret = -ESRCH;
-       read_lock_irq(&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;
                case IOPRIO_WHO_PGRP:
                        if (!who)
-                               who = process_group(current);
-                       do_each_task_pid(who, PIDTYPE_PGID, p) {
+                               pgrp = task_pgrp(current);
+                       else
+                               pgrp = find_vpid(who);
+                       do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
                                ret = set_task_ioprio(p, ioprio);
                                if (ret)
                                        break;
-                       } while_each_task_pid(who, 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);
 
@@ -97,13 +134,13 @@ asmlinkage int 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)
-                                       break;
+                                       goto free_uid;
                        } while_each_thread(g, p);
-
+free_uid:
                        if (who)
                                free_uid(user);
                        break;
@@ -111,39 +148,78 @@ asmlinkage int sys_ioprio_set(int which, int who, int ioprio)
                        ret = -EINVAL;
        }
 
-       read_unlock_irq(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }
 
-asmlinkage int sys_ioprio_get(int which, int who)
+static int get_task_ioprio(struct task_struct *p)
+{
+       int ret;
+
+       ret = security_task_getioprio(p);
+       if (ret)
+               goto out;
+       ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
+       if (p->io_context)
+               ret = p->io_context->ioprio;
+out:
+       return ret;
+}
+
+int ioprio_best(unsigned short aprio, unsigned short bprio)
+{
+       unsigned short aclass = IOPRIO_PRIO_CLASS(aprio);
+       unsigned short bclass = IOPRIO_PRIO_CLASS(bprio);
+
+       if (aclass == IOPRIO_CLASS_NONE)
+               aclass = IOPRIO_CLASS_BE;
+       if (bclass == IOPRIO_CLASS_NONE)
+               bclass = IOPRIO_CLASS_BE;
+
+       if (aclass == bclass)
+               return min(aprio, bprio);
+       if (aclass > bclass)
+               return bprio;
+       else
+               return aprio;
+}
+
+SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
 {
        struct task_struct *g, *p;
        struct user_struct *user;
+       struct pid *pgrp;
        int ret = -ESRCH;
+       int tmpio;
 
-       read_lock_irq(&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 = p->ioprio;
+                               ret = get_task_ioprio(p);
                        break;
                case IOPRIO_WHO_PGRP:
                        if (!who)
-                               who = process_group(current);
-                       do_each_task_pid(who, PIDTYPE_PGID, p) {
+                               pgrp = task_pgrp(current);
+                       else
+                               pgrp = find_vpid(who);
+                       do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
+                               tmpio = get_task_ioprio(p);
+                               if (tmpio < 0)
+                                       continue;
                                if (ret == -ESRCH)
-                                       ret = p->ioprio;
+                                       ret = tmpio;
                                else
-                                       ret = ioprio_best(ret, p->ioprio);
-                       } while_each_task_pid(who, PIDTYPE_PGID, p);
+                                       ret = ioprio_best(ret, tmpio);
+                       } 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);
 
@@ -151,12 +227,15 @@ asmlinkage int 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)
                                        continue;
                                if (ret == -ESRCH)
-                                       ret = p->ioprio;
+                                       ret = tmpio;
                                else
-                                       ret = ioprio_best(ret, p->ioprio);
+                                       ret = ioprio_best(ret, tmpio);
                        } while_each_thread(g, p);
 
                        if (who)
@@ -166,7 +245,6 @@ asmlinkage int sys_ioprio_get(int which, int who)
                        ret = -EINVAL;
        }
 
-       read_unlock_irq(&tasklist_lock);
+       rcu_read_unlock();
        return ret;
 }
-