X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fioprio.c;h=c4a1c3c65aac35ba999a4739fb3ed6549b5e1b75;hb=f698f1f7ad69f700dd1c754aa2b4aa7acbd51703;hp=78b1deae3fa2e1a9aaa4142fa83050b434840b90;hpb=e014ff8d4285b81f0de0719d8eee72bc50bfd4be;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 78b1dea..c4a1c3c 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -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
@@ -25,6 +25,7 @@
 #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)
 {
@@ -40,18 +41,28 @@ static int set_task_ioprio(struct task_struct *task, int ioprio)
 		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 && ioc->set_ioprio)
-		ioc->set_ioprio(ioc, ioprio);
+	if (!err) {
+		ioc->ioprio = ioprio;
+		ioc->ioprio_changed = 1;
+	}
 
 	task_unlock(task);
-	return 0;
+	return err;
 }
 
 asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
@@ -60,6 +71,7 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
 	int data = IOPRIO_PRIO_DATA(ioprio);
 	struct task_struct *p, *g;
 	struct user_struct *user;
+	struct pid *pgrp;
 	int ret;
 
 	switch (class) {
@@ -73,32 +85,41 @@ 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;
-	read_lock_irq(&tasklist_lock);
+	/*
+	 * 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);
 	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_task(pgrp, PIDTYPE_PGID, p) {
 				ret = set_task_ioprio(p, ioprio);
 				if (ret)
 					break;
-			} while_each_task_pid(who, PIDTYPE_PGID, p);
+			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 			break;
 		case IOPRIO_WHO_USER:
 			if (!who)
@@ -124,7 +145,7 @@ free_uid:
 			ret = -EINVAL;
 	}
 
-	read_unlock_irq(&tasklist_lock);
+	read_unlock(&tasklist_lock);
 	return ret;
 }
 
@@ -135,7 +156,9 @@ 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;
 }
@@ -145,11 +168,6 @@ int ioprio_best(unsigned short aprio, unsigned short bprio)
 	unsigned short aclass = IOPRIO_PRIO_CLASS(aprio);
 	unsigned short bclass = IOPRIO_PRIO_CLASS(bprio);
 
-	if (!ioprio_valid(aprio))
-		return bprio;
-	if (!ioprio_valid(bprio))
-		return aprio;
-
 	if (aclass == IOPRIO_CLASS_NONE)
 		aclass = IOPRIO_CLASS_BE;
 	if (bclass == IOPRIO_CLASS_NONE)
@@ -167,23 +185,26 @@ asmlinkage long sys_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);
+	read_lock(&tasklist_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;
 		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_task(pgrp, PIDTYPE_PGID, p) {
 				tmpio = get_task_ioprio(p);
 				if (tmpio < 0)
 					continue;
@@ -191,7 +212,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
 					ret = tmpio;
 				else
 					ret = ioprio_best(ret, tmpio);
-			} while_each_task_pid(who, PIDTYPE_PGID, p);
+			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 			break;
 		case IOPRIO_WHO_USER:
 			if (!who)
@@ -221,7 +242,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
 			ret = -EINVAL;
 	}
 
-	read_unlock_irq(&tasklist_lock);
+	read_unlock(&tasklist_lock);
 	return ret;
 }