2005-06-27 02:55:12 -06:00
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|
|
/*
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* fs/ioprio.c
|
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*
|
2006-09-04 07:41:16 -06:00
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* Copyright (C) 2004 Jens Axboe <axboe@kernel.dk>
|
2005-06-27 02:55:12 -06:00
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*
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* Helper functions for setting/querying io priorities of processes. The
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* system calls closely mimmick getpriority/setpriority, see the man page for
|
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|
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* those. The prio argument is a composite of prio class and prio data, where
|
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* the data argument has meaning within that class. The standard scheduling
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* classes have 8 distinct prio levels, with 0 being the highest prio and 7
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* being the lowest.
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*
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* IOW, setting BE scheduling class with prio 2 is done ala:
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*
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* unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
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*
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* ioprio_set(PRIO_PROCESS, pid, prio);
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*
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* See also Documentation/block/ioprio.txt
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*
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*/
|
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 02:04:11 -06:00
|
|
|
#include <linux/gfp.h>
|
2005-06-27 02:55:12 -06:00
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#include <linux/kernel.h>
|
2011-05-26 14:00:52 -06:00
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#include <linux/export.h>
|
2005-06-27 02:55:12 -06:00
|
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#include <linux/ioprio.h>
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#include <linux/blkdev.h>
|
2006-01-11 13:17:46 -07:00
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#include <linux/capability.h>
|
2005-11-08 08:57:02 -07:00
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#include <linux/syscalls.h>
|
2006-06-23 03:03:58 -06:00
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#include <linux/security.h>
|
2007-10-19 00:40:14 -06:00
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#include <linux/pid_namespace.h>
|
2005-06-27 02:55:12 -06:00
|
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|
2009-01-05 20:46:26 -07:00
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int set_task_ioprio(struct task_struct *task, int ioprio)
|
2005-06-27 02:55:12 -06:00
|
|
|
{
|
2006-06-23 03:03:58 -06:00
|
|
|
int err;
|
2005-06-27 02:55:12 -06:00
|
|
|
struct io_context *ioc;
|
2008-11-13 16:39:19 -07:00
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|
|
const struct cred *cred = current_cred(), *tcred;
|
2005-06-27 02:55:12 -06:00
|
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|
2008-11-13 16:39:19 -07:00
|
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|
rcu_read_lock();
|
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|
|
tcred = __task_cred(task);
|
2012-03-03 22:17:15 -07:00
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|
|
if (!uid_eq(tcred->uid, cred->euid) &&
|
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|
|
!uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) {
|
2008-11-13 16:39:19 -07:00
|
|
|
rcu_read_unlock();
|
2005-06-27 02:55:12 -06:00
|
|
|
return -EPERM;
|
2008-11-13 16:39:19 -07:00
|
|
|
}
|
|
|
|
rcu_read_unlock();
|
2005-06-27 02:55:12 -06:00
|
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|
2006-06-23 03:03:58 -06:00
|
|
|
err = security_task_setioprio(task, ioprio);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
block: make ioc get/put interface more conventional and fix race on alloction
Ignoring copy_io() during fork, io_context can be allocated from two
places - current_io_context() and set_task_ioprio(). The former is
always called from local task while the latter can be called from
different task. The synchornization between them are peculiar and
dubious.
* current_io_context() doesn't grab task_lock() and assumes that if it
saw %NULL ->io_context, it would stay that way until allocation and
assignment is complete. It has smp_wmb() between alloc/init and
assignment.
* set_task_ioprio() grabs task_lock() for assignment and does
smp_read_barrier_depends() between "ioc = task->io_context" and "if
(ioc)". Unfortunately, this doesn't achieve anything - the latter
is not a dependent load of the former. ie, if ioc itself were being
dereferenced "ioc->xxx", it would mean something (not sure what tho)
but as the code currently stands, the dependent read barrier is
noop.
As only one of the the two test-assignment sequences is task_lock()
protected, the task_lock() can't do much about race between the two.
Nothing prevents current_io_context() and set_task_ioprio() allocating
its own ioc for the same task and overwriting the other's.
Also, set_task_ioprio() can race with exiting task and create a new
ioc after exit_io_context() is finished.
ioc get/put doesn't have any reason to be complex. The only hot path
is accessing the existing ioc of %current, which is simple to achieve
given that ->io_context is never destroyed as long as the task is
alive. All other paths can happily go through task_lock() like all
other task sub structures without impacting anything.
This patch updates ioc get/put so that it becomes more conventional.
* alloc_io_context() is replaced with get_task_io_context(). This is
the only interface which can acquire access to ioc of another task.
On return, the caller has an explicit reference to the object which
should be put using put_io_context() afterwards.
* The functionality of current_io_context() remains the same but when
creating a new ioc, it shares the code path with
get_task_io_context() and always goes through task_lock().
* get_io_context() now means incrementing ref on an ioc which the
caller already has access to (be that an explicit refcnt or implicit
%current one).
* PF_EXITING inhibits creation of new io_context and once
exit_io_context() is finished, it's guaranteed that both ioc
acquisition functions return %NULL.
* All users are updated. Most are trivial but
smp_read_barrier_depends() removal from cfq_get_io_context() needs a
bit of explanation. I suppose the original intention was to ensure
ioc->ioprio is visible when set_task_ioprio() allocates new
io_context and installs it; however, this wouldn't have worked
because set_task_ioprio() doesn't have wmb between init and install.
There are other problems with this which will be fixed in another
patch.
* While at it, use NUMA_NO_NODE instead of -1 for wildcard node
specification.
-v2: Vivek spotted contamination from debug patch. Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-13 16:33:38 -07:00
|
|
|
ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
|
|
|
|
if (ioc) {
|
2012-03-19 16:10:59 -06:00
|
|
|
ioc->ioprio = ioprio;
|
2012-02-06 23:51:30 -07:00
|
|
|
put_io_context(ioc);
|
2008-01-24 00:52:45 -07:00
|
|
|
}
|
2005-06-27 02:55:12 -06:00
|
|
|
|
2008-01-24 00:52:45 -07:00
|
|
|
return err;
|
2005-06-27 02:55:12 -06:00
|
|
|
}
|
2009-01-05 20:46:26 -07:00
|
|
|
EXPORT_SYMBOL_GPL(set_task_ioprio);
|
2005-06-27 02:55:12 -06:00
|
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|
|
2009-01-14 06:14:30 -07:00
|
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|
SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
|
2005-06-27 02:55:12 -06:00
|
|
|
{
|
|
|
|
int class = IOPRIO_PRIO_CLASS(ioprio);
|
|
|
|
int data = IOPRIO_PRIO_DATA(ioprio);
|
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struct task_struct *p, *g;
|
|
|
|
struct user_struct *user;
|
2007-02-12 01:53:01 -07:00
|
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|
struct pid *pgrp;
|
2011-11-17 00:20:58 -07:00
|
|
|
kuid_t uid;
|
2005-06-27 02:55:12 -06:00
|
|
|
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;
|
2007-11-07 05:54:07 -07:00
|
|
|
case IOPRIO_CLASS_NONE:
|
|
|
|
if (data)
|
|
|
|
return -EINVAL;
|
|
|
|
break;
|
2005-06-27 02:55:12 -06:00
|
|
|
default:
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = -ESRCH;
|
2010-11-15 02:20:52 -07:00
|
|
|
rcu_read_lock();
|
2005-06-27 02:55:12 -06:00
|
|
|
switch (which) {
|
|
|
|
case IOPRIO_WHO_PROCESS:
|
|
|
|
if (!who)
|
|
|
|
p = current;
|
|
|
|
else
|
2007-10-19 00:40:16 -06:00
|
|
|
p = find_task_by_vpid(who);
|
2005-06-27 02:55:12 -06:00
|
|
|
if (p)
|
|
|
|
ret = set_task_ioprio(p, ioprio);
|
|
|
|
break;
|
|
|
|
case IOPRIO_WHO_PGRP:
|
|
|
|
if (!who)
|
2007-02-12 01:53:01 -07:00
|
|
|
pgrp = task_pgrp(current);
|
|
|
|
else
|
2007-10-19 00:40:14 -06:00
|
|
|
pgrp = find_vpid(who);
|
2008-08-20 15:09:17 -06:00
|
|
|
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
|
2005-06-27 02:55:12 -06:00
|
|
|
ret = set_task_ioprio(p, ioprio);
|
|
|
|
if (ret)
|
|
|
|
break;
|
2008-08-20 15:09:17 -06:00
|
|
|
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
|
2005-06-27 02:55:12 -06:00
|
|
|
break;
|
|
|
|
case IOPRIO_WHO_USER:
|
2011-11-17 00:20:58 -07:00
|
|
|
uid = make_kuid(current_user_ns(), who);
|
|
|
|
if (!uid_valid(uid))
|
|
|
|
break;
|
2005-06-27 02:55:12 -06:00
|
|
|
if (!who)
|
2008-11-13 16:39:18 -07:00
|
|
|
user = current_user();
|
2005-06-27 02:55:12 -06:00
|
|
|
else
|
2011-11-17 00:20:58 -07:00
|
|
|
user = find_user(uid);
|
2005-06-27 02:55:12 -06:00
|
|
|
|
|
|
|
if (!user)
|
|
|
|
break;
|
|
|
|
|
|
|
|
do_each_thread(g, p) {
|
2015-11-06 17:32:48 -07:00
|
|
|
if (!uid_eq(task_uid(p), uid) ||
|
|
|
|
!task_pid_vnr(p))
|
2005-06-27 02:55:12 -06:00
|
|
|
continue;
|
|
|
|
ret = set_task_ioprio(p, ioprio);
|
|
|
|
if (ret)
|
2006-08-21 00:33:23 -06:00
|
|
|
goto free_uid;
|
2005-06-27 02:55:12 -06:00
|
|
|
} while_each_thread(g, p);
|
2006-08-21 00:33:23 -06:00
|
|
|
free_uid:
|
2005-06-27 02:55:12 -06:00
|
|
|
if (who)
|
|
|
|
free_uid(user);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
ret = -EINVAL;
|
|
|
|
}
|
|
|
|
|
2010-11-15 02:20:52 -07:00
|
|
|
rcu_read_unlock();
|
2005-06-27 02:55:12 -06:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2006-06-30 02:55:49 -06:00
|
|
|
static int get_task_ioprio(struct task_struct *p)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = security_task_getioprio(p);
|
|
|
|
if (ret)
|
|
|
|
goto out;
|
2008-01-24 00:52:45 -07:00
|
|
|
ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
|
|
|
|
if (p->io_context)
|
|
|
|
ret = p->io_context->ioprio;
|
2006-06-30 02:55:49 -06:00
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2006-08-21 02:02:50 -06:00
|
|
|
int ioprio_best(unsigned short aprio, unsigned short bprio)
|
|
|
|
{
|
2014-10-30 13:43:38 -06:00
|
|
|
unsigned short aclass;
|
|
|
|
unsigned short bclass;
|
2006-08-21 02:02:50 -06:00
|
|
|
|
2014-10-30 13:43:38 -06:00
|
|
|
if (!ioprio_valid(aprio))
|
|
|
|
aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
|
|
|
|
if (!ioprio_valid(bprio))
|
|
|
|
bprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
|
2006-08-21 02:02:50 -06:00
|
|
|
|
2014-10-30 13:43:38 -06:00
|
|
|
aclass = IOPRIO_PRIO_CLASS(aprio);
|
|
|
|
bclass = IOPRIO_PRIO_CLASS(bprio);
|
2006-08-21 02:02:50 -06:00
|
|
|
if (aclass == bclass)
|
|
|
|
return min(aprio, bprio);
|
|
|
|
if (aclass > bclass)
|
|
|
|
return bprio;
|
|
|
|
else
|
|
|
|
return aprio;
|
|
|
|
}
|
|
|
|
|
2009-01-14 06:14:30 -07:00
|
|
|
SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
|
2005-06-27 02:55:12 -06:00
|
|
|
{
|
|
|
|
struct task_struct *g, *p;
|
|
|
|
struct user_struct *user;
|
2007-02-12 01:53:01 -07:00
|
|
|
struct pid *pgrp;
|
2011-11-17 00:20:58 -07:00
|
|
|
kuid_t uid;
|
2005-06-27 02:55:12 -06:00
|
|
|
int ret = -ESRCH;
|
2006-06-30 02:55:49 -06:00
|
|
|
int tmpio;
|
2005-06-27 02:55:12 -06:00
|
|
|
|
2010-11-15 02:20:52 -07:00
|
|
|
rcu_read_lock();
|
2005-06-27 02:55:12 -06:00
|
|
|
switch (which) {
|
|
|
|
case IOPRIO_WHO_PROCESS:
|
|
|
|
if (!who)
|
|
|
|
p = current;
|
|
|
|
else
|
2007-10-19 00:40:16 -06:00
|
|
|
p = find_task_by_vpid(who);
|
2005-06-27 02:55:12 -06:00
|
|
|
if (p)
|
2006-06-30 02:55:49 -06:00
|
|
|
ret = get_task_ioprio(p);
|
2005-06-27 02:55:12 -06:00
|
|
|
break;
|
|
|
|
case IOPRIO_WHO_PGRP:
|
|
|
|
if (!who)
|
2007-02-12 01:53:01 -07:00
|
|
|
pgrp = task_pgrp(current);
|
|
|
|
else
|
2007-10-19 00:40:14 -06:00
|
|
|
pgrp = find_vpid(who);
|
2008-08-20 15:09:17 -06:00
|
|
|
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
|
2006-06-30 02:55:49 -06:00
|
|
|
tmpio = get_task_ioprio(p);
|
|
|
|
if (tmpio < 0)
|
|
|
|
continue;
|
2005-06-27 02:55:12 -06:00
|
|
|
if (ret == -ESRCH)
|
2006-06-30 02:55:49 -06:00
|
|
|
ret = tmpio;
|
2005-06-27 02:55:12 -06:00
|
|
|
else
|
2006-06-30 02:55:49 -06:00
|
|
|
ret = ioprio_best(ret, tmpio);
|
2008-08-20 15:09:17 -06:00
|
|
|
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
|
2005-06-27 02:55:12 -06:00
|
|
|
break;
|
|
|
|
case IOPRIO_WHO_USER:
|
2011-11-17 00:20:58 -07:00
|
|
|
uid = make_kuid(current_user_ns(), who);
|
2005-06-27 02:55:12 -06:00
|
|
|
if (!who)
|
2008-11-13 16:39:18 -07:00
|
|
|
user = current_user();
|
2005-06-27 02:55:12 -06:00
|
|
|
else
|
2011-11-17 00:20:58 -07:00
|
|
|
user = find_user(uid);
|
2005-06-27 02:55:12 -06:00
|
|
|
|
|
|
|
if (!user)
|
|
|
|
break;
|
|
|
|
|
|
|
|
do_each_thread(g, p) {
|
2015-11-06 17:32:48 -07:00
|
|
|
if (!uid_eq(task_uid(p), user->uid) ||
|
|
|
|
!task_pid_vnr(p))
|
2005-06-27 02:55:12 -06:00
|
|
|
continue;
|
2006-06-30 02:55:49 -06:00
|
|
|
tmpio = get_task_ioprio(p);
|
|
|
|
if (tmpio < 0)
|
|
|
|
continue;
|
2005-06-27 02:55:12 -06:00
|
|
|
if (ret == -ESRCH)
|
2006-06-30 02:55:49 -06:00
|
|
|
ret = tmpio;
|
2005-06-27 02:55:12 -06:00
|
|
|
else
|
2006-06-30 02:55:49 -06:00
|
|
|
ret = ioprio_best(ret, tmpio);
|
2005-06-27 02:55:12 -06:00
|
|
|
} while_each_thread(g, p);
|
|
|
|
|
|
|
|
if (who)
|
|
|
|
free_uid(user);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
ret = -EINVAL;
|
|
|
|
}
|
|
|
|
|
2010-11-15 02:20:52 -07:00
|
|
|
rcu_read_unlock();
|
2005-06-27 02:55:12 -06:00
|
|
|
return ret;
|
|
|
|
}
|