Root/
| Source at commit 9845c1745d3d531a5b9544f5322c62bfb4d4e9bc created 1 year 2 months ago. By Xiangfu, rtc: jz4740 fix hwclock give time out | |
|---|---|
| 1 | /* |
| 2 | * fs/ioprio.c |
| 3 | * |
| 4 | * Copyright (C) 2004 Jens Axboe <axboe@kernel.dk> |
| 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/gfp.h> |
| 23 | #include <linux/kernel.h> |
| 24 | #include <linux/export.h> |
| 25 | #include <linux/ioprio.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/capability.h> |
| 28 | #include <linux/syscalls.h> |
| 29 | #include <linux/security.h> |
| 30 | #include <linux/pid_namespace.h> |
| 31 | |
| 32 | int set_task_ioprio(struct task_struct *task, int ioprio) |
| 33 | { |
| 34 | int err; |
| 35 | struct io_context *ioc; |
| 36 | const struct cred *cred = current_cred(), *tcred; |
| 37 | |
| 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(); |
| 43 | return -EPERM; |
| 44 | } |
| 45 | rcu_read_unlock(); |
| 46 | |
| 47 | err = security_task_setioprio(task, ioprio); |
| 48 | if (err) |
| 49 | return err; |
| 50 | |
| 51 | task_lock(task); |
| 52 | do { |
| 53 | ioc = task->io_context; |
| 54 | /* see wmb() in current_io_context() */ |
| 55 | smp_read_barrier_depends(); |
| 56 | if (ioc) |
| 57 | break; |
| 58 | |
| 59 | ioc = alloc_io_context(GFP_ATOMIC, -1); |
| 60 | if (!ioc) { |
| 61 | err = -ENOMEM; |
| 62 | break; |
| 63 | } |
| 64 | task->io_context = ioc; |
| 65 | } while (1); |
| 66 | |
| 67 | if (!err) { |
| 68 | ioc->ioprio = ioprio; |
| 69 | ioc->ioprio_changed = 1; |
| 70 | } |
| 71 | |
| 72 | task_unlock(task); |
| 73 | return err; |
| 74 | } |
| 75 | EXPORT_SYMBOL_GPL(set_task_ioprio); |
| 76 | |
| 77 | SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio) |
| 78 | { |
| 79 | int class = IOPRIO_PRIO_CLASS(ioprio); |
| 80 | int data = IOPRIO_PRIO_DATA(ioprio); |
| 81 | struct task_struct *p, *g; |
| 82 | struct user_struct *user; |
| 83 | struct pid *pgrp; |
| 84 | int ret; |
| 85 | |
| 86 | switch (class) { |
| 87 | case IOPRIO_CLASS_RT: |
| 88 | if (!capable(CAP_SYS_ADMIN)) |
| 89 | return -EPERM; |
| 90 | /* fall through, rt has prio field too */ |
| 91 | case IOPRIO_CLASS_BE: |
| 92 | if (data >= IOPRIO_BE_NR || data < 0) |
| 93 | return -EINVAL; |
| 94 | |
| 95 | break; |
| 96 | case IOPRIO_CLASS_IDLE: |
| 97 | break; |
| 98 | case IOPRIO_CLASS_NONE: |
| 99 | if (data) |
| 100 | return -EINVAL; |
| 101 | break; |
| 102 | default: |
| 103 | return -EINVAL; |
| 104 | } |
| 105 | |
| 106 | ret = -ESRCH; |
| 107 | rcu_read_lock(); |
| 108 | switch (which) { |
| 109 | case IOPRIO_WHO_PROCESS: |
| 110 | if (!who) |
| 111 | p = current; |
| 112 | else |
| 113 | p = find_task_by_vpid(who); |
| 114 | if (p) |
| 115 | ret = set_task_ioprio(p, ioprio); |
| 116 | break; |
| 117 | case IOPRIO_WHO_PGRP: |
| 118 | if (!who) |
| 119 | pgrp = task_pgrp(current); |
| 120 | else |
| 121 | pgrp = find_vpid(who); |
| 122 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
| 123 | ret = set_task_ioprio(p, ioprio); |
| 124 | if (ret) |
| 125 | break; |
| 126 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
| 127 | break; |
| 128 | case IOPRIO_WHO_USER: |
| 129 | if (!who) |
| 130 | user = current_user(); |
| 131 | else |
| 132 | user = find_user(who); |
| 133 | |
| 134 | if (!user) |
| 135 | break; |
| 136 | |
| 137 | do_each_thread(g, p) { |
| 138 | if (__task_cred(p)->uid != who) |
| 139 | continue; |
| 140 | ret = set_task_ioprio(p, ioprio); |
| 141 | if (ret) |
| 142 | goto free_uid; |
| 143 | } while_each_thread(g, p); |
| 144 | free_uid: |
| 145 | if (who) |
| 146 | free_uid(user); |
| 147 | break; |
| 148 | default: |
| 149 | ret = -EINVAL; |
| 150 | } |
| 151 | |
| 152 | rcu_read_unlock(); |
| 153 | return ret; |
| 154 | } |
| 155 | |
| 156 | static int get_task_ioprio(struct task_struct *p) |
| 157 | { |
| 158 | int ret; |
| 159 | |
| 160 | ret = security_task_getioprio(p); |
| 161 | if (ret) |
| 162 | goto out; |
| 163 | ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); |
| 164 | if (p->io_context) |
| 165 | ret = p->io_context->ioprio; |
| 166 | out: |
| 167 | return ret; |
| 168 | } |
| 169 | |
| 170 | int ioprio_best(unsigned short aprio, unsigned short bprio) |
| 171 | { |
| 172 | unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); |
| 173 | unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); |
| 174 | |
| 175 | if (aclass == IOPRIO_CLASS_NONE) |
| 176 | aclass = IOPRIO_CLASS_BE; |
| 177 | if (bclass == IOPRIO_CLASS_NONE) |
| 178 | bclass = IOPRIO_CLASS_BE; |
| 179 | |
| 180 | if (aclass == bclass) |
| 181 | return min(aprio, bprio); |
| 182 | if (aclass > bclass) |
| 183 | return bprio; |
| 184 | else |
| 185 | return aprio; |
| 186 | } |
| 187 | |
| 188 | SYSCALL_DEFINE2(ioprio_get, int, which, int, who) |
| 189 | { |
| 190 | struct task_struct *g, *p; |
| 191 | struct user_struct *user; |
| 192 | struct pid *pgrp; |
| 193 | int ret = -ESRCH; |
| 194 | int tmpio; |
| 195 | |
| 196 | rcu_read_lock(); |
| 197 | switch (which) { |
| 198 | case IOPRIO_WHO_PROCESS: |
| 199 | if (!who) |
| 200 | p = current; |
| 201 | else |
| 202 | p = find_task_by_vpid(who); |
| 203 | if (p) |
| 204 | ret = get_task_ioprio(p); |
| 205 | break; |
| 206 | case IOPRIO_WHO_PGRP: |
| 207 | if (!who) |
| 208 | pgrp = task_pgrp(current); |
| 209 | else |
| 210 | pgrp = find_vpid(who); |
| 211 | do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { |
| 212 | tmpio = get_task_ioprio(p); |
| 213 | if (tmpio < 0) |
| 214 | continue; |
| 215 | if (ret == -ESRCH) |
| 216 | ret = tmpio; |
| 217 | else |
| 218 | ret = ioprio_best(ret, tmpio); |
| 219 | } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); |
| 220 | break; |
| 221 | case IOPRIO_WHO_USER: |
| 222 | if (!who) |
| 223 | user = current_user(); |
| 224 | else |
| 225 | user = find_user(who); |
| 226 | |
| 227 | if (!user) |
| 228 | break; |
| 229 | |
| 230 | do_each_thread(g, p) { |
| 231 | if (__task_cred(p)->uid != user->uid) |
| 232 | continue; |
| 233 | tmpio = get_task_ioprio(p); |
| 234 | if (tmpio < 0) |
| 235 | continue; |
| 236 | if (ret == -ESRCH) |
| 237 | ret = tmpio; |
| 238 | else |
| 239 | ret = ioprio_best(ret, tmpio); |
| 240 | } while_each_thread(g, p); |
| 241 | |
| 242 | if (who) |
| 243 | free_uid(user); |
| 244 | break; |
| 245 | default: |
| 246 | ret = -EINVAL; |
| 247 | } |
| 248 | |
| 249 | rcu_read_unlock(); |
| 250 | return ret; |
| 251 | } |
| 252 | |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9
