Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1 | /* |
| 2 | * fs/ioprio.c |
| 3 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 4 | * Copyright (C) 2004 Jens Axboe <axboe@kernel.dk> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 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 | */ |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 22 | #include <linux/gfp.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 23 | #include <linux/kernel.h> |
Paul Gortmaker | afeacc8 | 2011-05-26 16:00:52 -0400 | [diff] [blame] | 24 | #include <linux/export.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 25 | #include <linux/ioprio.h> |
| 26 | #include <linux/blkdev.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 27 | #include <linux/capability.h> |
Adrian Bunk | 9abdc4c | 2005-11-08 16:57:02 +0100 | [diff] [blame] | 28 | #include <linux/syscalls.h> |
James Morris | 03e6806 | 2006-06-23 02:03:58 -0700 | [diff] [blame] | 29 | #include <linux/security.h> |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 30 | #include <linux/pid_namespace.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 31 | |
Theodore Ts'o | b3881f7 | 2009-01-05 22:46:26 -0500 | [diff] [blame] | 32 | int set_task_ioprio(struct task_struct *task, int ioprio) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 33 | { |
James Morris | 03e6806 | 2006-06-23 02:03:58 -0700 | [diff] [blame] | 34 | int err; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 35 | struct io_context *ioc; |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 36 | const struct cred *cred = current_cred(), *tcred; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 37 | |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 38 | rcu_read_lock(); |
| 39 | tcred = __task_cred(task); |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 40 | if (!uid_eq(tcred->uid, cred->euid) && |
| 41 | !uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) { |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 42 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 43 | return -EPERM; |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 44 | } |
| 45 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 46 | |
James Morris | 03e6806 | 2006-06-23 02:03:58 -0700 | [diff] [blame] | 47 | err = security_task_setioprio(task, ioprio); |
| 48 | if (err) |
| 49 | return err; |
| 50 | |
Tejun Heo | 6e736be | 2011-12-14 00:33:38 +0100 | [diff] [blame] | 51 | ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); |
| 52 | if (ioc) { |
Tejun Heo | dc86900 | 2011-12-14 00:33:38 +0100 | [diff] [blame] | 53 | ioc_ioprio_changed(ioc, ioprio); |
Tejun Heo | 11a3122 | 2012-02-07 07:51:30 +0100 | [diff] [blame] | 54 | put_io_context(ioc); |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 55 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 56 | |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 57 | return err; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 58 | } |
Theodore Ts'o | b3881f7 | 2009-01-05 22:46:26 -0500 | [diff] [blame] | 59 | EXPORT_SYMBOL_GPL(set_task_ioprio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 60 | |
Heiko Carstens | 938bb9f | 2009-01-14 14:14:30 +0100 | [diff] [blame] | 61 | SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 62 | { |
| 63 | int class = IOPRIO_PRIO_CLASS(ioprio); |
| 64 | int data = IOPRIO_PRIO_DATA(ioprio); |
| 65 | struct task_struct *p, *g; |
| 66 | struct user_struct *user; |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 67 | struct pid *pgrp; |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 68 | kuid_t uid; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 69 | int ret; |
| 70 | |
| 71 | switch (class) { |
| 72 | case IOPRIO_CLASS_RT: |
| 73 | if (!capable(CAP_SYS_ADMIN)) |
| 74 | return -EPERM; |
| 75 | /* fall through, rt has prio field too */ |
| 76 | case IOPRIO_CLASS_BE: |
| 77 | if (data >= IOPRIO_BE_NR || data < 0) |
| 78 | return -EINVAL; |
| 79 | |
| 80 | break; |
| 81 | case IOPRIO_CLASS_IDLE: |
| 82 | break; |
Jens Axboe | 8ec680e | 2007-11-07 13:54:07 +0100 | [diff] [blame] | 83 | case IOPRIO_CLASS_NONE: |
| 84 | if (data) |
| 85 | return -EINVAL; |
| 86 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 87 | default: |
| 88 | return -EINVAL; |
| 89 | } |
| 90 | |
| 91 | ret = -ESRCH; |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 92 | rcu_read_lock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 93 | switch (which) { |
| 94 | case IOPRIO_WHO_PROCESS: |
| 95 | if (!who) |
| 96 | p = current; |
| 97 | else |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 98 | p = find_task_by_vpid(who); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 99 | if (p) |
| 100 | ret = set_task_ioprio(p, ioprio); |
| 101 | break; |
| 102 | case IOPRIO_WHO_PGRP: |
| 103 | if (!who) |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 104 | pgrp = task_pgrp(current); |
| 105 | else |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 106 | pgrp = find_vpid(who); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 107 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 108 | ret = set_task_ioprio(p, ioprio); |
| 109 | if (ret) |
| 110 | break; |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 111 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 112 | break; |
| 113 | case IOPRIO_WHO_USER: |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 114 | uid = make_kuid(current_user_ns(), who); |
| 115 | if (!uid_valid(uid)) |
| 116 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 117 | if (!who) |
David Howells | 86a264a | 2008-11-14 10:39:18 +1100 | [diff] [blame] | 118 | user = current_user(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 119 | else |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 120 | user = find_user(uid); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 121 | |
| 122 | if (!user) |
| 123 | break; |
| 124 | |
| 125 | do_each_thread(g, p) { |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 126 | if (!uid_eq(task_uid(p), uid)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 127 | continue; |
| 128 | ret = set_task_ioprio(p, ioprio); |
| 129 | if (ret) |
Oleg Nesterov | 78bd4d4 | 2006-08-21 08:33:23 +0200 | [diff] [blame] | 130 | goto free_uid; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 131 | } while_each_thread(g, p); |
Oleg Nesterov | 78bd4d4 | 2006-08-21 08:33:23 +0200 | [diff] [blame] | 132 | free_uid: |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 133 | if (who) |
| 134 | free_uid(user); |
| 135 | break; |
| 136 | default: |
| 137 | ret = -EINVAL; |
| 138 | } |
| 139 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 140 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 141 | return ret; |
| 142 | } |
| 143 | |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 144 | static int get_task_ioprio(struct task_struct *p) |
| 145 | { |
| 146 | int ret; |
| 147 | |
| 148 | ret = security_task_getioprio(p); |
| 149 | if (ret) |
| 150 | goto out; |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 151 | ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); |
| 152 | if (p->io_context) |
| 153 | ret = p->io_context->ioprio; |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 154 | out: |
| 155 | return ret; |
| 156 | } |
| 157 | |
Oleg Nesterov | e014ff8 | 2006-08-21 10:02:50 +0200 | [diff] [blame] | 158 | int ioprio_best(unsigned short aprio, unsigned short bprio) |
| 159 | { |
| 160 | unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); |
| 161 | unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); |
| 162 | |
Oleg Nesterov | e014ff8 | 2006-08-21 10:02:50 +0200 | [diff] [blame] | 163 | if (aclass == IOPRIO_CLASS_NONE) |
| 164 | aclass = IOPRIO_CLASS_BE; |
| 165 | if (bclass == IOPRIO_CLASS_NONE) |
| 166 | bclass = IOPRIO_CLASS_BE; |
| 167 | |
| 168 | if (aclass == bclass) |
| 169 | return min(aprio, bprio); |
| 170 | if (aclass > bclass) |
| 171 | return bprio; |
| 172 | else |
| 173 | return aprio; |
| 174 | } |
| 175 | |
Heiko Carstens | 938bb9f | 2009-01-14 14:14:30 +0100 | [diff] [blame] | 176 | SYSCALL_DEFINE2(ioprio_get, int, which, int, who) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 177 | { |
| 178 | struct task_struct *g, *p; |
| 179 | struct user_struct *user; |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 180 | struct pid *pgrp; |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 181 | kuid_t uid; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 182 | int ret = -ESRCH; |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 183 | int tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 184 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 185 | rcu_read_lock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 186 | switch (which) { |
| 187 | case IOPRIO_WHO_PROCESS: |
| 188 | if (!who) |
| 189 | p = current; |
| 190 | else |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 191 | p = find_task_by_vpid(who); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 192 | if (p) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 193 | ret = get_task_ioprio(p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 194 | break; |
| 195 | case IOPRIO_WHO_PGRP: |
| 196 | if (!who) |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 197 | pgrp = task_pgrp(current); |
| 198 | else |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 199 | pgrp = find_vpid(who); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 200 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 201 | tmpio = get_task_ioprio(p); |
| 202 | if (tmpio < 0) |
| 203 | continue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 204 | if (ret == -ESRCH) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 205 | ret = tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 206 | else |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 207 | ret = ioprio_best(ret, tmpio); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 208 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 209 | break; |
| 210 | case IOPRIO_WHO_USER: |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 211 | uid = make_kuid(current_user_ns(), who); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 212 | if (!who) |
David Howells | 86a264a | 2008-11-14 10:39:18 +1100 | [diff] [blame] | 213 | user = current_user(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 214 | else |
Eric W. Biederman | 7b44ab9 | 2011-11-16 23:20:58 -0800 | [diff] [blame] | 215 | user = find_user(uid); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 216 | |
| 217 | if (!user) |
| 218 | break; |
| 219 | |
| 220 | do_each_thread(g, p) { |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 221 | if (!uid_eq(task_uid(p), user->uid)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 222 | continue; |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 223 | tmpio = get_task_ioprio(p); |
| 224 | if (tmpio < 0) |
| 225 | continue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 226 | if (ret == -ESRCH) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 227 | ret = tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 228 | else |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 229 | ret = ioprio_best(ret, tmpio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 230 | } while_each_thread(g, p); |
| 231 | |
| 232 | if (who) |
| 233 | free_uid(user); |
| 234 | break; |
| 235 | default: |
| 236 | ret = -EINVAL; |
| 237 | } |
| 238 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 239 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 240 | return ret; |
| 241 | } |