]>
Commit | Line | Data |
---|---|---|
22e2c507 JA |
1 | /* |
2 | * fs/ioprio.c | |
3 | * | |
0fe23479 | 4 | * Copyright (C) 2004 Jens Axboe <axboe@kernel.dk> |
22e2c507 JA |
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 | */ | |
5a0e3ad6 | 22 | #include <linux/gfp.h> |
22e2c507 | 23 | #include <linux/kernel.h> |
afeacc8c | 24 | #include <linux/export.h> |
22e2c507 | 25 | #include <linux/ioprio.h> |
5b825c3a | 26 | #include <linux/cred.h> |
22e2c507 | 27 | #include <linux/blkdev.h> |
16f7e0fe | 28 | #include <linux/capability.h> |
8703e8a4 | 29 | #include <linux/sched/user.h> |
9abdc4cd | 30 | #include <linux/syscalls.h> |
03e68060 | 31 | #include <linux/security.h> |
b488893a | 32 | #include <linux/pid_namespace.h> |
22e2c507 | 33 | |
b3881f74 | 34 | int set_task_ioprio(struct task_struct *task, int ioprio) |
22e2c507 | 35 | { |
03e68060 | 36 | int err; |
22e2c507 | 37 | struct io_context *ioc; |
c69e8d9c | 38 | const struct cred *cred = current_cred(), *tcred; |
22e2c507 | 39 | |
c69e8d9c DH |
40 | rcu_read_lock(); |
41 | tcred = __task_cred(task); | |
8e96e3b7 EB |
42 | if (!uid_eq(tcred->uid, cred->euid) && |
43 | !uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) { | |
c69e8d9c | 44 | rcu_read_unlock(); |
22e2c507 | 45 | return -EPERM; |
c69e8d9c DH |
46 | } |
47 | rcu_read_unlock(); | |
22e2c507 | 48 | |
03e68060 JM |
49 | err = security_task_setioprio(task, ioprio); |
50 | if (err) | |
51 | return err; | |
52 | ||
6e736be7 TH |
53 | ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); |
54 | if (ioc) { | |
2b566fa5 | 55 | ioc->ioprio = ioprio; |
11a3122f | 56 | put_io_context(ioc); |
fd0928df | 57 | } |
22e2c507 | 58 | |
fd0928df | 59 | return err; |
22e2c507 | 60 | } |
b3881f74 | 61 | EXPORT_SYMBOL_GPL(set_task_ioprio); |
22e2c507 | 62 | |
938bb9f5 | 63 | SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio) |
22e2c507 JA |
64 | { |
65 | int class = IOPRIO_PRIO_CLASS(ioprio); | |
66 | int data = IOPRIO_PRIO_DATA(ioprio); | |
67 | struct task_struct *p, *g; | |
68 | struct user_struct *user; | |
41487c65 | 69 | struct pid *pgrp; |
7b44ab97 | 70 | kuid_t uid; |
22e2c507 JA |
71 | int ret; |
72 | ||
73 | switch (class) { | |
74 | case IOPRIO_CLASS_RT: | |
75 | if (!capable(CAP_SYS_ADMIN)) | |
76 | return -EPERM; | |
77 | /* fall through, rt has prio field too */ | |
78 | case IOPRIO_CLASS_BE: | |
79 | if (data >= IOPRIO_BE_NR || data < 0) | |
80 | return -EINVAL; | |
81 | ||
82 | break; | |
83 | case IOPRIO_CLASS_IDLE: | |
84 | break; | |
8ec680e4 JA |
85 | case IOPRIO_CLASS_NONE: |
86 | if (data) | |
87 | return -EINVAL; | |
88 | break; | |
22e2c507 JA |
89 | default: |
90 | return -EINVAL; | |
91 | } | |
92 | ||
93 | ret = -ESRCH; | |
d69b78ba | 94 | rcu_read_lock(); |
22e2c507 JA |
95 | switch (which) { |
96 | case IOPRIO_WHO_PROCESS: | |
97 | if (!who) | |
98 | p = current; | |
99 | else | |
228ebcbe | 100 | p = find_task_by_vpid(who); |
22e2c507 JA |
101 | if (p) |
102 | ret = set_task_ioprio(p, ioprio); | |
103 | break; | |
104 | case IOPRIO_WHO_PGRP: | |
105 | if (!who) | |
41487c65 EB |
106 | pgrp = task_pgrp(current); |
107 | else | |
b488893a | 108 | pgrp = find_vpid(who); |
2d70b68d | 109 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
22e2c507 JA |
110 | ret = set_task_ioprio(p, ioprio); |
111 | if (ret) | |
112 | break; | |
2d70b68d | 113 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
22e2c507 JA |
114 | break; |
115 | case IOPRIO_WHO_USER: | |
7b44ab97 EB |
116 | uid = make_kuid(current_user_ns(), who); |
117 | if (!uid_valid(uid)) | |
118 | break; | |
22e2c507 | 119 | if (!who) |
86a264ab | 120 | user = current_user(); |
22e2c507 | 121 | else |
7b44ab97 | 122 | user = find_user(uid); |
22e2c507 JA |
123 | |
124 | if (!user) | |
125 | break; | |
126 | ||
612dafab | 127 | for_each_process_thread(g, p) { |
8639b461 BS |
128 | if (!uid_eq(task_uid(p), uid) || |
129 | !task_pid_vnr(p)) | |
22e2c507 JA |
130 | continue; |
131 | ret = set_task_ioprio(p, ioprio); | |
132 | if (ret) | |
78bd4d48 | 133 | goto free_uid; |
612dafab | 134 | } |
78bd4d48 | 135 | free_uid: |
22e2c507 JA |
136 | if (who) |
137 | free_uid(user); | |
138 | break; | |
139 | default: | |
140 | ret = -EINVAL; | |
141 | } | |
142 | ||
d69b78ba | 143 | rcu_read_unlock(); |
22e2c507 JA |
144 | return ret; |
145 | } | |
146 | ||
a1836a42 DQ |
147 | static int get_task_ioprio(struct task_struct *p) |
148 | { | |
149 | int ret; | |
150 | ||
151 | ret = security_task_getioprio(p); | |
152 | if (ret) | |
153 | goto out; | |
fd0928df | 154 | ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); |
8ba86821 | 155 | task_lock(p); |
fd0928df JA |
156 | if (p->io_context) |
157 | ret = p->io_context->ioprio; | |
8ba86821 | 158 | task_unlock(p); |
a1836a42 DQ |
159 | out: |
160 | return ret; | |
161 | } | |
162 | ||
e014ff8d ON |
163 | int ioprio_best(unsigned short aprio, unsigned short bprio) |
164 | { | |
ece9c72a JK |
165 | unsigned short aclass; |
166 | unsigned short bclass; | |
e014ff8d | 167 | |
ece9c72a JK |
168 | if (!ioprio_valid(aprio)) |
169 | aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM); | |
170 | if (!ioprio_valid(bprio)) | |
171 | bprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM); | |
e014ff8d | 172 | |
ece9c72a JK |
173 | aclass = IOPRIO_PRIO_CLASS(aprio); |
174 | bclass = IOPRIO_PRIO_CLASS(bprio); | |
e014ff8d ON |
175 | if (aclass == bclass) |
176 | return min(aprio, bprio); | |
177 | if (aclass > bclass) | |
178 | return bprio; | |
179 | else | |
180 | return aprio; | |
181 | } | |
182 | ||
938bb9f5 | 183 | SYSCALL_DEFINE2(ioprio_get, int, which, int, who) |
22e2c507 JA |
184 | { |
185 | struct task_struct *g, *p; | |
186 | struct user_struct *user; | |
41487c65 | 187 | struct pid *pgrp; |
7b44ab97 | 188 | kuid_t uid; |
22e2c507 | 189 | int ret = -ESRCH; |
a1836a42 | 190 | int tmpio; |
22e2c507 | 191 | |
d69b78ba | 192 | rcu_read_lock(); |
22e2c507 JA |
193 | switch (which) { |
194 | case IOPRIO_WHO_PROCESS: | |
195 | if (!who) | |
196 | p = current; | |
197 | else | |
228ebcbe | 198 | p = find_task_by_vpid(who); |
22e2c507 | 199 | if (p) |
a1836a42 | 200 | ret = get_task_ioprio(p); |
22e2c507 JA |
201 | break; |
202 | case IOPRIO_WHO_PGRP: | |
203 | if (!who) | |
41487c65 EB |
204 | pgrp = task_pgrp(current); |
205 | else | |
b488893a | 206 | pgrp = find_vpid(who); |
2d70b68d | 207 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
a1836a42 DQ |
208 | tmpio = get_task_ioprio(p); |
209 | if (tmpio < 0) | |
210 | continue; | |
22e2c507 | 211 | if (ret == -ESRCH) |
a1836a42 | 212 | ret = tmpio; |
22e2c507 | 213 | else |
a1836a42 | 214 | ret = ioprio_best(ret, tmpio); |
2d70b68d | 215 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
22e2c507 JA |
216 | break; |
217 | case IOPRIO_WHO_USER: | |
7b44ab97 | 218 | uid = make_kuid(current_user_ns(), who); |
22e2c507 | 219 | if (!who) |
86a264ab | 220 | user = current_user(); |
22e2c507 | 221 | else |
7b44ab97 | 222 | user = find_user(uid); |
22e2c507 JA |
223 | |
224 | if (!user) | |
225 | break; | |
226 | ||
612dafab | 227 | for_each_process_thread(g, p) { |
8639b461 BS |
228 | if (!uid_eq(task_uid(p), user->uid) || |
229 | !task_pid_vnr(p)) | |
22e2c507 | 230 | continue; |
a1836a42 DQ |
231 | tmpio = get_task_ioprio(p); |
232 | if (tmpio < 0) | |
233 | continue; | |
22e2c507 | 234 | if (ret == -ESRCH) |
a1836a42 | 235 | ret = tmpio; |
22e2c507 | 236 | else |
a1836a42 | 237 | ret = ioprio_best(ret, tmpio); |
612dafab | 238 | } |
22e2c507 JA |
239 | |
240 | if (who) | |
241 | free_uid(user); | |
242 | break; | |
243 | default: | |
244 | ret = -EINVAL; | |
245 | } | |
246 | ||
d69b78ba | 247 | rcu_read_unlock(); |
22e2c507 JA |
248 | return ret; |
249 | } |