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[media] rc-core: cleanup rc_register_device pt2
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Now that rc_register_device() is reorganised, the dev->initialized
hack can be removed. Any driver which calls rc_register_device()
must be prepared for the device to go live immediately.

The dev->initialized commits that are relevant are commit c73bbaa
("[media] rc-core: don't lock device at rc_register_device()") and
commit 08aeb7c ("[media] rc: add locking to fix register/show race").

The original problem was that show_protocols() would access
dev->rc_map.* and various other bits which are now properly
initialized before device_add() is called.

At the same time, remove the bogus "device is being removed" check.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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@Alphix @mchehab
Alphix authored and mchehab committed Jun 13, 2017
1 parent f56928a commit 18726a3
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Showing 2 changed files with 10 additions and 59 deletions.
67 changes: 10 additions & 57 deletions drivers/media/rc/rc-main.c
View file
Expand Up @@ -15,7 +15,6 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <media/rc-core.h>
#include <linux/atomic.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/input.h>
Expand Down Expand Up @@ -934,8 +933,8 @@ static bool lirc_is_present(void)
* It returns the protocol names of supported protocols.
* Enabled protocols are printed in brackets.
*
* dev->lock is taken to guard against races between device
* registration, store_protocols and show_protocols.
* dev->lock is taken to guard against races between
* store_protocols and show_protocols.
*/
static ssize_t show_protocols(struct device *device,
struct device_attribute *mattr, char *buf)
Expand All @@ -945,13 +944,6 @@ static ssize_t show_protocols(struct device *device,
char *tmp = buf;
int i;

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

mutex_lock(&dev->lock);

enabled = dev->enabled_protocols;
Expand Down Expand Up @@ -1106,8 +1098,8 @@ static void ir_raw_load_modules(u64 *protocols)
* See parse_protocol_change() for the valid commands.
* Returns @len on success or a negative error code.
*
* dev->lock is taken to guard against races between device
* registration, store_protocols and show_protocols.
* dev->lock is taken to guard against races between
* store_protocols and show_protocols.
*/
static ssize_t store_protocols(struct device *device,
struct device_attribute *mattr,
Expand All @@ -1119,13 +1111,6 @@ static ssize_t store_protocols(struct device *device,
u64 old_protocols, new_protocols;
ssize_t rc;

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

IR_dprintk(1, "Normal protocol change requested\n");
current_protocols = &dev->enabled_protocols;
filter = &dev->scancode_filter;
Expand Down Expand Up @@ -1200,7 +1185,7 @@ static ssize_t store_protocols(struct device *device,
* Bits of the filter value corresponding to set bits in the filter mask are
* compared against input scancodes and non-matching scancodes are discarded.
*
* dev->lock is taken to guard against races between device registration,
* dev->lock is taken to guard against races between
* store_filter and show_filter.
*/
static ssize_t show_filter(struct device *device,
Expand All @@ -1212,13 +1197,6 @@ static ssize_t show_filter(struct device *device,
struct rc_scancode_filter *filter;
u32 val;

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

mutex_lock(&dev->lock);

if (fattr->type == RC_FILTER_NORMAL)
Expand Down Expand Up @@ -1251,7 +1229,7 @@ static ssize_t show_filter(struct device *device,
* Bits of the filter value corresponding to set bits in the filter mask are
* compared against input scancodes and non-matching scancodes are discarded.
*
* dev->lock is taken to guard against races between device registration,
* dev->lock is taken to guard against races between
* store_filter and show_filter.
*/
static ssize_t store_filter(struct device *device,
Expand All @@ -1265,13 +1243,6 @@ static ssize_t store_filter(struct device *device,
unsigned long val;
int (*set_filter)(struct rc_dev *dev, struct rc_scancode_filter *filter);

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

ret = kstrtoul(buf, 0, &val);
if (ret < 0)
return ret;
Expand Down Expand Up @@ -1372,8 +1343,8 @@ static const char * const proto_variant_names[] = {
* It returns the protocol names of supported protocols.
* The enabled protocols are printed in brackets.
*
* dev->lock is taken to guard against races between device
* registration, store_protocols and show_protocols.
* dev->lock is taken to guard against races between
* store_wakeup_protocols and show_wakeup_protocols.
*/
static ssize_t show_wakeup_protocols(struct device *device,
struct device_attribute *mattr,
Expand All @@ -1385,13 +1356,6 @@ static ssize_t show_wakeup_protocols(struct device *device,
char *tmp = buf;
int i;

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

mutex_lock(&dev->lock);

allowed = dev->allowed_wakeup_protocols;
Expand Down Expand Up @@ -1431,8 +1395,8 @@ static ssize_t show_wakeup_protocols(struct device *device,
* It is trigged by writing to /sys/class/rc/rc?/wakeup_protocols.
* Returns @len on success or a negative error code.
*
* dev->lock is taken to guard against races between device
* registration, store_protocols and show_protocols.
* dev->lock is taken to guard against races between
* store_wakeup_protocols and show_wakeup_protocols.
*/
static ssize_t store_wakeup_protocols(struct device *device,
struct device_attribute *mattr,
Expand All @@ -1444,13 +1408,6 @@ static ssize_t store_wakeup_protocols(struct device *device,
u64 allowed;
int i;

/* Device is being removed */
if (!dev)
return -EINVAL;

if (!atomic_read(&dev->initialized))
return -ERESTARTSYS;

mutex_lock(&dev->lock);

allowed = dev->allowed_wakeup_protocols;
Expand Down Expand Up @@ -1773,7 +1730,6 @@ int rc_register_device(struct rc_dev *dev)
dev->minor = minor;
dev_set_name(&dev->dev, "rc%u", dev->minor);
dev_set_drvdata(&dev->dev, dev);
atomic_set(&dev->initialized, 0);

dev->dev.groups = dev->sysfs_groups;
if (dev->driver_type != RC_DRIVER_IR_RAW_TX)
Expand Down Expand Up @@ -1819,9 +1775,6 @@ int rc_register_device(struct rc_dev *dev)
goto out_rx;
}

/* Allow the RC sysfs nodes to be accessible */
atomic_set(&dev->initialized, 1);

IR_dprintk(1, "Registered rc%u (driver: %s)\n",
dev->minor,
dev->driver_name ? dev->driver_name : "unknown");
Expand Down
2 changes: 0 additions & 2 deletions include/media/rc-core.h
View file
Expand Up @@ -70,7 +70,6 @@ enum rc_filter_type {
/**
* struct rc_dev - represents a remote control device
* @dev: driver model's view of this device
* @initialized: 1 if the device init has completed, 0 otherwise
* @managed_alloc: devm_rc_allocate_device was used to create rc_dev
* @sysfs_groups: sysfs attribute groups
* @input_name: name of the input child device
Expand Down Expand Up @@ -137,7 +136,6 @@ enum rc_filter_type {
*/
struct rc_dev {
struct device dev;
atomic_t initialized;
bool managed_alloc;
const struct attribute_group *sysfs_groups[5];
const char *input_name;
Expand Down

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