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); |
| 40 | if (tcred->uid != cred->euid && |
| 41 | tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) { |
| 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; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 68 | int ret; |
| 69 | |
| 70 | switch (class) { |
| 71 | case IOPRIO_CLASS_RT: |
| 72 | if (!capable(CAP_SYS_ADMIN)) |
| 73 | return -EPERM; |
| 74 | /* fall through, rt has prio field too */ |
| 75 | case IOPRIO_CLASS_BE: |
| 76 | if (data >= IOPRIO_BE_NR || data < 0) |
| 77 | return -EINVAL; |
| 78 | |
| 79 | break; |
| 80 | case IOPRIO_CLASS_IDLE: |
| 81 | break; |
Jens Axboe | 8ec680e | 2007-11-07 13:54:07 +0100 | [diff] [blame] | 82 | case IOPRIO_CLASS_NONE: |
| 83 | if (data) |
| 84 | return -EINVAL; |
| 85 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 86 | default: |
| 87 | return -EINVAL; |
| 88 | } |
| 89 | |
| 90 | ret = -ESRCH; |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 91 | rcu_read_lock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 92 | switch (which) { |
| 93 | case IOPRIO_WHO_PROCESS: |
| 94 | if (!who) |
| 95 | p = current; |
| 96 | else |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 97 | p = find_task_by_vpid(who); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 98 | if (p) |
| 99 | ret = set_task_ioprio(p, ioprio); |
| 100 | break; |
| 101 | case IOPRIO_WHO_PGRP: |
| 102 | if (!who) |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 103 | pgrp = task_pgrp(current); |
| 104 | else |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 105 | pgrp = find_vpid(who); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 106 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 107 | ret = set_task_ioprio(p, ioprio); |
| 108 | if (ret) |
| 109 | break; |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 110 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 111 | break; |
| 112 | case IOPRIO_WHO_USER: |
| 113 | if (!who) |
David Howells | 86a264a | 2008-11-14 10:39:18 +1100 | [diff] [blame] | 114 | user = current_user(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 115 | else |
| 116 | user = find_user(who); |
| 117 | |
| 118 | if (!user) |
| 119 | break; |
| 120 | |
| 121 | do_each_thread(g, p) { |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 122 | if (__task_cred(p)->uid != who) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 123 | continue; |
| 124 | ret = set_task_ioprio(p, ioprio); |
| 125 | if (ret) |
Oleg Nesterov | 78bd4d4 | 2006-08-21 08:33:23 +0200 | [diff] [blame] | 126 | goto free_uid; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 127 | } while_each_thread(g, p); |
Oleg Nesterov | 78bd4d4 | 2006-08-21 08:33:23 +0200 | [diff] [blame] | 128 | free_uid: |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 129 | if (who) |
| 130 | free_uid(user); |
| 131 | break; |
| 132 | default: |
| 133 | ret = -EINVAL; |
| 134 | } |
| 135 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 136 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 137 | return ret; |
| 138 | } |
| 139 | |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 140 | static int get_task_ioprio(struct task_struct *p) |
| 141 | { |
| 142 | int ret; |
| 143 | |
| 144 | ret = security_task_getioprio(p); |
| 145 | if (ret) |
| 146 | goto out; |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 147 | ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); |
Dirk Vogt | 966f01f | 2016-11-02 12:10:10 +0100 | [diff] [blame^] | 148 | task_lock(p); |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 149 | if (p->io_context) |
| 150 | ret = p->io_context->ioprio; |
Dirk Vogt | 966f01f | 2016-11-02 12:10:10 +0100 | [diff] [blame^] | 151 | task_unlock(p); |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 152 | out: |
| 153 | return ret; |
| 154 | } |
| 155 | |
Oleg Nesterov | e014ff8 | 2006-08-21 10:02:50 +0200 | [diff] [blame] | 156 | int ioprio_best(unsigned short aprio, unsigned short bprio) |
| 157 | { |
| 158 | unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); |
| 159 | unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); |
| 160 | |
Oleg Nesterov | e014ff8 | 2006-08-21 10:02:50 +0200 | [diff] [blame] | 161 | if (aclass == IOPRIO_CLASS_NONE) |
| 162 | aclass = IOPRIO_CLASS_BE; |
| 163 | if (bclass == IOPRIO_CLASS_NONE) |
| 164 | bclass = IOPRIO_CLASS_BE; |
| 165 | |
| 166 | if (aclass == bclass) |
| 167 | return min(aprio, bprio); |
| 168 | if (aclass > bclass) |
| 169 | return bprio; |
| 170 | else |
| 171 | return aprio; |
| 172 | } |
| 173 | |
Heiko Carstens | 938bb9f | 2009-01-14 14:14:30 +0100 | [diff] [blame] | 174 | SYSCALL_DEFINE2(ioprio_get, int, which, int, who) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 175 | { |
| 176 | struct task_struct *g, *p; |
| 177 | struct user_struct *user; |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 178 | struct pid *pgrp; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 179 | int ret = -ESRCH; |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 180 | int tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 181 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 182 | rcu_read_lock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 183 | switch (which) { |
| 184 | case IOPRIO_WHO_PROCESS: |
| 185 | if (!who) |
| 186 | p = current; |
| 187 | else |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 188 | p = find_task_by_vpid(who); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 189 | if (p) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 190 | ret = get_task_ioprio(p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 191 | break; |
| 192 | case IOPRIO_WHO_PGRP: |
| 193 | if (!who) |
Eric W. Biederman | 41487c6 | 2007-02-12 00:53:01 -0800 | [diff] [blame] | 194 | pgrp = task_pgrp(current); |
| 195 | else |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 196 | pgrp = find_vpid(who); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 197 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 198 | tmpio = get_task_ioprio(p); |
| 199 | if (tmpio < 0) |
| 200 | continue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 201 | if (ret == -ESRCH) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 202 | ret = tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 203 | else |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 204 | ret = ioprio_best(ret, tmpio); |
Ken Chen | 2d70b68 | 2008-08-20 14:09:17 -0700 | [diff] [blame] | 205 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 206 | break; |
| 207 | case IOPRIO_WHO_USER: |
| 208 | if (!who) |
David Howells | 86a264a | 2008-11-14 10:39:18 +1100 | [diff] [blame] | 209 | user = current_user(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 210 | else |
| 211 | user = find_user(who); |
| 212 | |
| 213 | if (!user) |
| 214 | break; |
| 215 | |
| 216 | do_each_thread(g, p) { |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 217 | if (__task_cred(p)->uid != user->uid) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 218 | continue; |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 219 | tmpio = get_task_ioprio(p); |
| 220 | if (tmpio < 0) |
| 221 | continue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 222 | if (ret == -ESRCH) |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 223 | ret = tmpio; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 224 | else |
David Quigley | a1836a4 | 2006-06-30 01:55:49 -0700 | [diff] [blame] | 225 | ret = ioprio_best(ret, tmpio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 226 | } while_each_thread(g, p); |
| 227 | |
| 228 | if (who) |
| 229 | free_uid(user); |
| 230 | break; |
| 231 | default: |
| 232 | ret = -EINVAL; |
| 233 | } |
| 234 | |
Greg Thelen | d69b78b | 2010-11-15 10:20:52 +0100 | [diff] [blame] | 235 | rcu_read_unlock(); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 236 | return ret; |
| 237 | } |