Revision 4d59b6ccf000862beed6fc0765d3209f98a8d8a2 authored by Tejun Heo on 08 February 2017, 22:30:56 UTC, committed by Linus Torvalds on 08 February 2017, 23:41:43 UTC
Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") converted both cpumask printing and parsing functions to use nr_cpu_ids instead of nr_cpumask_bits. While this was okay for the printing functions as it just picked one of the two output formats that we were alternating between depending on a kernel config, doing the same for parsing wasn't okay. nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS. We can always use nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can be more efficient to use NR_CPUS when we can get away with it. Converting the printing functions to nr_cpu_ids makes sense because it affects how the masks get presented to userspace and doesn't break anything; however, using nr_cpu_ids for parsing functions can incorrectly leave the higher bits uninitialized while reading in these masks from userland. As all testing and comparison functions use nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks can erroneously yield false negative results. This made the taskstats interface incorrectly return -EINVAL even when the inputs were correct. Fix it by restoring the parse functions to use nr_cpumask_bits instead of nr_cpu_ids. Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de> Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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lcd.h
/*
* LCD Lowlevel Control Abstraction
*
* Copyright (C) 2003,2004 Hewlett-Packard Company
*
*/
#ifndef _LINUX_LCD_H
#define _LINUX_LCD_H
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/fb.h>
/* Notes on locking:
*
* lcd_device->ops_lock is an internal backlight lock protecting the ops
* field and no code outside the core should need to touch it.
*
* Access to set_power() is serialised by the update_lock mutex since
* most drivers seem to need this and historically get it wrong.
*
* Most drivers don't need locking on their get_power() method.
* If yours does, you need to implement it in the driver. You can use the
* update_lock mutex if appropriate.
*
* Any other use of the locks below is probably wrong.
*/
struct lcd_device;
struct fb_info;
struct lcd_properties {
/* The maximum value for contrast (read-only) */
int max_contrast;
};
struct lcd_ops {
/* Get the LCD panel power status (0: full on, 1..3: controller
power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
int (*get_power)(struct lcd_device *);
/*
* Enable or disable power to the LCD(0: on; 4: off, see FB_BLANK_XXX)
* and this callback would be called proir to fb driver's callback.
*
* P.S. note that if early_set_power is not NULL then early fb notifier
* would be registered.
*/
int (*early_set_power)(struct lcd_device *, int power);
/* revert the effects of the early blank event. */
int (*r_early_set_power)(struct lcd_device *, int power);
/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
int (*set_power)(struct lcd_device *, int power);
/* Get the current contrast setting (0-max_contrast) */
int (*get_contrast)(struct lcd_device *);
/* Set LCD panel contrast */
int (*set_contrast)(struct lcd_device *, int contrast);
/* Set LCD panel mode (resolutions ...) */
int (*set_mode)(struct lcd_device *, struct fb_videomode *);
/* Check if given framebuffer device is the one LCD is bound to;
return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
int (*check_fb)(struct lcd_device *, struct fb_info *);
};
struct lcd_device {
struct lcd_properties props;
/* This protects the 'ops' field. If 'ops' is NULL, the driver that
registered this device has been unloaded, and if class_get_devdata()
points to something in the body of that driver, it is also invalid. */
struct mutex ops_lock;
/* If this is NULL, the backing module is unloaded */
struct lcd_ops *ops;
/* Serialise access to set_power method */
struct mutex update_lock;
/* The framebuffer notifier block */
struct notifier_block fb_notif;
struct device dev;
};
struct lcd_platform_data {
/* reset lcd panel device. */
int (*reset)(struct lcd_device *ld);
/* on or off to lcd panel. if 'enable' is 0 then
lcd power off and 1, lcd power on. */
int (*power_on)(struct lcd_device *ld, int enable);
/* it indicates whether lcd panel was enabled
from bootloader or not. */
int lcd_enabled;
/* it means delay for stable time when it becomes low to high
or high to low that is dependent on whether reset gpio is
low active or high active. */
unsigned int reset_delay;
/* stable time needing to become lcd power on. */
unsigned int power_on_delay;
/* stable time needing to become lcd power off. */
unsigned int power_off_delay;
/* it could be used for any purpose. */
void *pdata;
};
static inline void lcd_set_power(struct lcd_device *ld, int power)
{
mutex_lock(&ld->update_lock);
if (ld->ops && ld->ops->set_power)
ld->ops->set_power(ld, power);
mutex_unlock(&ld->update_lock);
}
extern struct lcd_device *lcd_device_register(const char *name,
struct device *parent, void *devdata, struct lcd_ops *ops);
extern struct lcd_device *devm_lcd_device_register(struct device *dev,
const char *name, struct device *parent,
void *devdata, struct lcd_ops *ops);
extern void lcd_device_unregister(struct lcd_device *ld);
extern void devm_lcd_device_unregister(struct device *dev,
struct lcd_device *ld);
#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
static inline void * lcd_get_data(struct lcd_device *ld_dev)
{
return dev_get_drvdata(&ld_dev->dev);
}
#endif
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