1 files changed, 172 insertions, 0 deletions
diff --git a/fs/ioprio.c b/fs/ioprio.c
new file mode 100644
index 000000000000..663e420636d6
--- /dev/null
+++ b/fs/ioprio.c
@@ -0,0 +1,172 @@
+/*
+ * fs/ioprio.c
+ *
+ * Copyright (C) 2004 Jens Axboe <axboe@suse.de>
+ *
+ * Helper functions for setting/querying io priorities of processes. The
+ * system calls closely mimmick getpriority/setpriority, see the man page for
+ * those. The prio argument is a composite of prio class and prio data, where
+ * the data argument has meaning within that class. The standard scheduling
+ * classes have 8 distinct prio levels, with 0 being the highest prio and 7
+ * being the lowest.
+ *
+ * IOW, setting BE scheduling class with prio 2 is done ala:
+ *
+ * unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
+ *
+ * ioprio_set(PRIO_PROCESS, pid, prio);
+ *
+ * See also Documentation/block/ioprio.txt
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/ioprio.h>
+#include <linux/blkdev.h>
+static int set_task_ioprio(struct task_struct *task, int ioprio)
+{
+        struct io_context *ioc;
+        if (task->uid != current->euid &&
+            task->uid != current->uid && !capable(CAP_SYS_NICE))
+                return -EPERM;
+        task_lock(task);
+        task->ioprio = ioprio;
+        ioc = task->io_context;
+        if (ioc && ioc->set_ioprio)
+                ioc->set_ioprio(ioc, ioprio);
+        task_unlock(task);
+        return 0;
+}
+asmlinkage int sys_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;
+        int ret;
+        switch (class) {
+                case IOPRIO_CLASS_RT:
+                        if (!capable(CAP_SYS_ADMIN))
+                                return -EPERM;
+                        /* fall through, rt has prio field too */
+                case IOPRIO_CLASS_BE:
+                        if (data >= IOPRIO_BE_NR || data < 0)
+                                return -EINVAL;
+                        break;
+                case IOPRIO_CLASS_IDLE:
+                        break;
+                default:
+                        return -EINVAL;
+        }
+        ret = -ESRCH;
+        read_lock_irq(&tasklist_lock);
+        switch (which) {
+                case IOPRIO_WHO_PROCESS:
+                        if (!who)
+                                p = current;
+                        else
+                                p = find_task_by_pid(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) {
+                                ret = set_task_ioprio(p, ioprio);
+                                if (ret)
+                                        break;
+                        } while_each_task_pid(who, PIDTYPE_PGID, p);
+                        break;
+                case IOPRIO_WHO_USER:
+                        if (!who)
+                                user = current->user;
+                        else
+                                user = find_user(who);
+                        if (!user)
+                                break;
+                        do_each_thread(g, p) {
+                                if (p->uid != who)
+                                        continue;
+                                ret = set_task_ioprio(p, ioprio);
+                                if (ret)
+                                        break;
+                        } while_each_thread(g, p);
+                        if (who)
+                                free_uid(user);
+                        break;
+                default:
+                        ret = -EINVAL;
+        }
+        read_unlock_irq(&tasklist_lock);
+        return ret;
+}
+asmlinkage int sys_ioprio_get(int which, int who)
+{
+        struct task_struct *g, *p;
+        struct user_struct *user;
+        int ret = -ESRCH;
+        read_lock_irq(&tasklist_lock);
+        switch (which) {
+                case IOPRIO_WHO_PROCESS:
+                        if (!who)
+                                p = current;
+                        else
+                                p = find_task_by_pid(who);
+                        if (p)
+                                ret = p->ioprio;
+                        break;
+                case IOPRIO_WHO_PGRP:
+                        if (!who)
+                                who = process_group(current);
+                        do_each_task_pid(who, PIDTYPE_PGID, p) {
+                                if (ret == -ESRCH)
+                                        ret = p->ioprio;
+                                else
+                                        ret = ioprio_best(ret, p->ioprio);
+                        } while_each_task_pid(who, PIDTYPE_PGID, p);
+                        break;
+                case IOPRIO_WHO_USER:
+                        if (!who)
+                                user = current->user;
+                        else
+                                user = find_user(who);
+                        if (!user)
+                                break;
+                        do_each_thread(g, p) {
+                                if (p->uid != user->uid)
+                                        continue;
+                                if (ret == -ESRCH)
+                                        ret = p->ioprio;
+                                else
+                                        ret = ioprio_best(ret, p->ioprio);
+                        } while_each_thread(g, p);
+                        if (who)
+                                free_uid(user);
+                        break;
+                default:
+                        ret = -EINVAL;
+        }
+        read_unlock_irq(&tasklist_lock);
+        return ret;
+}

diff --git a/fs/ioprio.c b/fs/ioprio.c new file mode 100644 index 000000000000..663e420636d6 --- /dev/null +++ b/fs/ioprio.c
@@ -0,0 +1,172 @@
	1	/*
	2	* fs/ioprio.c
	3	*
	4	* Copyright (C) 2004 Jens Axboe <axboe@suse.de>
	5	*
	6	* Helper functions for setting/querying io priorities of processes. The
	7	* system calls closely mimmick getpriority/setpriority, see the man page for
	8	* those. The prio argument is a composite of prio class and prio data, where
	9	* the data argument has meaning within that class. The standard scheduling
	10	* classes have 8 distinct prio levels, with 0 being the highest prio and 7
	11	* being the lowest.
	12	*
	13	* IOW, setting BE scheduling class with prio 2 is done ala:
	14	*
	15	* unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) \| 2;
	16	*
	17	* ioprio_set(PRIO_PROCESS, pid, prio);
	18	*
	19	* See also Documentation/block/ioprio.txt
	20	*
	21	*/
	22	#include <linux/kernel.h>
	23	#include <linux/ioprio.h>
	24	#include <linux/blkdev.h>
	25
	26	static int set_task_ioprio(struct task_struct *task, int ioprio)
	27	{
	28	struct io_context *ioc;
	29
	30	if (task->uid != current->euid &&
	31	task->uid != current->uid && !capable(CAP_SYS_NICE))
	32	return -EPERM;
	33
	34	task_lock(task);
	35
	36	task->ioprio = ioprio;
	37
	38	ioc = task->io_context;
	39	if (ioc && ioc->set_ioprio)
	40	ioc->set_ioprio(ioc, ioprio);
	41
	42	task_unlock(task);
	43	return 0;
	44	}
	45
	46	asmlinkage int sys_ioprio_set(int which, int who, int ioprio)
	47	{
	48	int class = IOPRIO_PRIO_CLASS(ioprio);
	49	int data = IOPRIO_PRIO_DATA(ioprio);
	50	struct task_struct p, g;
	51	struct user_struct *user;
	52	int ret;
	53
	54	switch (class) {
	55	case IOPRIO_CLASS_RT:
	56	if (!capable(CAP_SYS_ADMIN))
	57	return -EPERM;
	58	/* fall through, rt has prio field too */
	59	case IOPRIO_CLASS_BE:
	60	if (data >= IOPRIO_BE_NR \|\| data < 0)
	61	return -EINVAL;
	62
	63	break;
	64	case IOPRIO_CLASS_IDLE:
	65	break;
	66	default:
	67	return -EINVAL;
	68	}
	69
	70	ret = -ESRCH;
	71	read_lock_irq(&tasklist_lock);
	72	switch (which) {
	73	case IOPRIO_WHO_PROCESS:
	74	if (!who)
	75	p = current;
	76	else
	77	p = find_task_by_pid(who);
	78	if (p)
	79	ret = set_task_ioprio(p, ioprio);
	80	break;
	81	case IOPRIO_WHO_PGRP:
	82	if (!who)
	83	who = process_group(current);
	84	do_each_task_pid(who, PIDTYPE_PGID, p) {
	85	ret = set_task_ioprio(p, ioprio);
	86	if (ret)
	87	break;
	88	} while_each_task_pid(who, PIDTYPE_PGID, p);
	89	break;
	90	case IOPRIO_WHO_USER:
	91	if (!who)
	92	user = current->user;
	93	else
	94	user = find_user(who);
	95
	96	if (!user)
	97	break;
	98
	99	do_each_thread(g, p) {
	100	if (p->uid != who)
	101	continue;
	102	ret = set_task_ioprio(p, ioprio);
	103	if (ret)
	104	break;
	105	} while_each_thread(g, p);
	106
	107	if (who)
	108	free_uid(user);
	109	break;
	110	default:
	111	ret = -EINVAL;
	112	}
	113
	114	read_unlock_irq(&tasklist_lock);
	115	return ret;
	116	}
	117
	118	asmlinkage int sys_ioprio_get(int which, int who)
	119	{
	120	struct task_struct g, p;
	121	struct user_struct *user;
	122	int ret = -ESRCH;
	123
	124	read_lock_irq(&tasklist_lock);
	125	switch (which) {
	126	case IOPRIO_WHO_PROCESS:
	127	if (!who)
	128	p = current;
	129	else
	130	p = find_task_by_pid(who);
	131	if (p)
	132	ret = p->ioprio;
	133	break;
	134	case IOPRIO_WHO_PGRP:
	135	if (!who)
	136	who = process_group(current);
	137	do_each_task_pid(who, PIDTYPE_PGID, p) {
	138	if (ret == -ESRCH)
	139	ret = p->ioprio;
	140	else
	141	ret = ioprio_best(ret, p->ioprio);
	142	} while_each_task_pid(who, PIDTYPE_PGID, p);
	143	break;
	144	case IOPRIO_WHO_USER:
	145	if (!who)
	146	user = current->user;
	147	else
	148	user = find_user(who);
	149
	150	if (!user)
	151	break;
	152
	153	do_each_thread(g, p) {
	154	if (p->uid != user->uid)
	155	continue;
	156	if (ret == -ESRCH)
	157	ret = p->ioprio;
	158	else
	159	ret = ioprio_best(ret, p->ioprio);
	160	} while_each_thread(g, p);
	161
	162	if (who)
	163	free_uid(user);
	164	break;
	165	default:
	166	ret = -EINVAL;
	167	}
	168
	169	read_unlock_irq(&tasklist_lock);
	170	return ret;
	171	}
	172