Revision bce0b6c51ac76fc0e763262a6c2a9d05e486f0d8 authored by Steven Rostedt (Red Hat) on 21 August 2014, 03:57:04 UTC, committed by Steven Rostedt on 22 August 2014, 19:24:12 UTC
Now that a ftrace_hash can be shared by multiple ftrace_ops, they can dec the rec->flags by more than once (one per those that share the ftrace_hash). This means that the tramp_hash may not have a hash item when it was added. For example, if two ftrace_ops share a hash for a ftrace record, and the first ops has a trampoline, when it adds itself it will set the rec->flags TRAMP flag and increments its nr_trampolines counter. When the second ops is added, it must clear that tramp flag but also decrement the other ops that shares its hash. As the update to the function callbacks has not yet been performed, the other ops will not have the tramp hash set yet and it can not be used to know to decrement its nr_trampolines. Luckily, the tramp_hash does not need to be used. As the ftrace_mutex is held, a ops with a trampoline to a record during an update of another ops that shares the record will have its func_hash pointing to it. Since a trampoline can only be set for a record if only one ops is attached to it, we can just check if the record has a trampoline (the FTRACE_FL_TRAMP flag is set) and then find the ops that has this record in its hashes. Also added some output to help debug when things go wrong. Cc: stable@vger.kernel.org # 3.16+ (apply after 3.17-rc4 is out) Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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windfarm_lm75_sensor.c
/*
* Windfarm PowerMac thermal control. LM75 sensor
*
* (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
* <benh@kernel.crashing.org>
*
* Released under the term of the GNU GPL v2.
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>
#include <asm/pmac_low_i2c.h>
#include "windfarm.h"
#define VERSION "1.0"
#undef DEBUG
#ifdef DEBUG
#define DBG(args...) printk(args)
#else
#define DBG(args...) do { } while(0)
#endif
struct wf_lm75_sensor {
int ds1775 : 1;
int inited : 1;
struct i2c_client *i2c;
struct wf_sensor sens;
};
#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
{
struct wf_lm75_sensor *lm = wf_to_lm75(sr);
s32 data;
if (lm->i2c == NULL)
return -ENODEV;
/* Init chip if necessary */
if (!lm->inited) {
u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
sr->name, cfg);
/* clear shutdown bit, keep other settings as left by
* the firmware for now
*/
cfg_new = cfg & ~0x01;
i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
lm->inited = 1;
/* If we just powered it up, let's wait 200 ms */
msleep(200);
}
/* Read temperature register */
data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
data <<= 8;
*value = data;
return 0;
}
static void wf_lm75_release(struct wf_sensor *sr)
{
struct wf_lm75_sensor *lm = wf_to_lm75(sr);
kfree(lm);
}
static struct wf_sensor_ops wf_lm75_ops = {
.get_value = wf_lm75_get,
.release = wf_lm75_release,
.owner = THIS_MODULE,
};
static int wf_lm75_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct wf_lm75_sensor *lm;
int rc, ds1775 = id->driver_data;
const char *name, *loc;
DBG("wf_lm75: creating %s device at address 0x%02x\n",
ds1775 ? "ds1775" : "lm75", client->addr);
loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
if (!loc) {
dev_warn(&client->dev, "Missing hwsensor-location property!\n");
return -ENXIO;
}
/* Usual rant about sensor names not beeing very consistent in
* the device-tree, oh well ...
* Add more entries below as you deal with more setups
*/
if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
name = "hd-temp";
else if (!strcmp(loc, "Incoming Air Temp"))
name = "incoming-air-temp";
else if (!strcmp(loc, "ODD Temp"))
name = "optical-drive-temp";
else if (!strcmp(loc, "HD Temp"))
name = "hard-drive-temp";
else if (!strcmp(loc, "PCI SLOTS"))
name = "slots-temp";
else if (!strcmp(loc, "CPU A INLET"))
name = "cpu-inlet-temp-0";
else if (!strcmp(loc, "CPU B INLET"))
name = "cpu-inlet-temp-1";
else
return -ENXIO;
lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
if (lm == NULL)
return -ENODEV;
lm->inited = 0;
lm->ds1775 = ds1775;
lm->i2c = client;
lm->sens.name = name;
lm->sens.ops = &wf_lm75_ops;
i2c_set_clientdata(client, lm);
rc = wf_register_sensor(&lm->sens);
if (rc)
kfree(lm);
return rc;
}
static int wf_lm75_remove(struct i2c_client *client)
{
struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
/* Mark client detached */
lm->i2c = NULL;
/* release sensor */
wf_unregister_sensor(&lm->sens);
return 0;
}
static const struct i2c_device_id wf_lm75_id[] = {
{ "MAC,lm75", 0 },
{ "MAC,ds1775", 1 },
{ }
};
MODULE_DEVICE_TABLE(i2c, wf_lm75_id);
static struct i2c_driver wf_lm75_driver = {
.driver = {
.name = "wf_lm75",
},
.probe = wf_lm75_probe,
.remove = wf_lm75_remove,
.id_table = wf_lm75_id,
};
module_i2c_driver(wf_lm75_driver);
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");
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