Revision 1c1e093cbf6d3a7576ba0bd10363362a1c5c74ee authored by Stefan Weinhuber on 12 May 2010, 07:32:11 UTC, committed by Martin Schwidefsky on 12 May 2010, 07:32:26 UTC
The various dasd_sleep_on functions use a global wait queue when waiting for a cqr. The wait condition checks the status and devlist fields of the cqr to determine if it is safe to continue. This evaluation may return true, although the tasklet has not finished processing of the cqr and the callback function has not been called yet. When the callback is finally called, the data in the cqr may already be invalid. The sleep_on wait condition needs a safe way to determine if the tasklet has finished processing. Use the callback_data field of the cqr to store a token, which is set by the callback function itself. Cc: <stable@kernel.org> Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 parent cea0d76
res_counter.c
/*
* resource cgroups
*
* Copyright 2007 OpenVZ SWsoft Inc
*
* Author: Pavel Emelianov <xemul@openvz.org>
*
*/
#include <linux/types.h>
#include <linux/parser.h>
#include <linux/fs.h>
#include <linux/res_counter.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
void res_counter_init(struct res_counter *counter, struct res_counter *parent)
{
spin_lock_init(&counter->lock);
counter->limit = RESOURCE_MAX;
counter->soft_limit = RESOURCE_MAX;
counter->parent = parent;
}
int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
{
if (counter->usage + val > counter->limit) {
counter->failcnt++;
return -ENOMEM;
}
counter->usage += val;
if (counter->usage > counter->max_usage)
counter->max_usage = counter->usage;
return 0;
}
int res_counter_charge(struct res_counter *counter, unsigned long val,
struct res_counter **limit_fail_at)
{
int ret;
unsigned long flags;
struct res_counter *c, *u;
*limit_fail_at = NULL;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
spin_lock(&c->lock);
ret = res_counter_charge_locked(c, val);
spin_unlock(&c->lock);
if (ret < 0) {
*limit_fail_at = c;
goto undo;
}
}
ret = 0;
goto done;
undo:
for (u = counter; u != c; u = u->parent) {
spin_lock(&u->lock);
res_counter_uncharge_locked(u, val);
spin_unlock(&u->lock);
}
done:
local_irq_restore(flags);
return ret;
}
void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
{
if (WARN_ON(counter->usage < val))
val = counter->usage;
counter->usage -= val;
}
void res_counter_uncharge(struct res_counter *counter, unsigned long val)
{
unsigned long flags;
struct res_counter *c;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
spin_lock(&c->lock);
res_counter_uncharge_locked(c, val);
spin_unlock(&c->lock);
}
local_irq_restore(flags);
}
static inline unsigned long long *
res_counter_member(struct res_counter *counter, int member)
{
switch (member) {
case RES_USAGE:
return &counter->usage;
case RES_MAX_USAGE:
return &counter->max_usage;
case RES_LIMIT:
return &counter->limit;
case RES_FAILCNT:
return &counter->failcnt;
case RES_SOFT_LIMIT:
return &counter->soft_limit;
};
BUG();
return NULL;
}
ssize_t res_counter_read(struct res_counter *counter, int member,
const char __user *userbuf, size_t nbytes, loff_t *pos,
int (*read_strategy)(unsigned long long val, char *st_buf))
{
unsigned long long *val;
char buf[64], *s;
s = buf;
val = res_counter_member(counter, member);
if (read_strategy)
s += read_strategy(*val, s);
else
s += sprintf(s, "%llu\n", *val);
return simple_read_from_buffer((void __user *)userbuf, nbytes,
pos, buf, s - buf);
}
u64 res_counter_read_u64(struct res_counter *counter, int member)
{
return *res_counter_member(counter, member);
}
int res_counter_memparse_write_strategy(const char *buf,
unsigned long long *res)
{
char *end;
/* return RESOURCE_MAX(unlimited) if "-1" is specified */
if (*buf == '-') {
*res = simple_strtoull(buf + 1, &end, 10);
if (*res != 1 || *end != '\0')
return -EINVAL;
*res = RESOURCE_MAX;
return 0;
}
/* FIXME - make memparse() take const char* args */
*res = memparse((char *)buf, &end);
if (*end != '\0')
return -EINVAL;
*res = PAGE_ALIGN(*res);
return 0;
}
int res_counter_write(struct res_counter *counter, int member,
const char *buf, write_strategy_fn write_strategy)
{
char *end;
unsigned long flags;
unsigned long long tmp, *val;
if (write_strategy) {
if (write_strategy(buf, &tmp))
return -EINVAL;
} else {
tmp = simple_strtoull(buf, &end, 10);
if (*end != '\0')
return -EINVAL;
}
spin_lock_irqsave(&counter->lock, flags);
val = res_counter_member(counter, member);
*val = tmp;
spin_unlock_irqrestore(&counter->lock, flags);
return 0;
}
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