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driver-core: extend dev_printk() to pass structured data

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Extends dev_printk() to attach a dictionary with a device identifier
and the driver core subsystem name to logged messages, which makes
dev_prink() reliable machine-readable. In addition to the printed
plain text message, it creates these properties:
    SUBSYSTEM=     - the driver-core subsytem name
    DEVICE=
      b12:8        - block dev_t
      c127:3       - char dev_t
      n8           - netdev ifindex
      +sound:card0 - subsystem:devname

Tested-by: William Douglas <william.douglas@intel.com>
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kay Sievers 2012-05-03 02:29:59 +02:00 committed by Greg Kroah-Hartman
parent e11fea92e1
commit c4e00daaa9
1 changed files with 49 additions and 3 deletions
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52
drivers/base/core.c
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@ -25,6 +25,7 @@
#include <linux/mutex.h>
#include <linux/async.h>
#include <linux/pm_runtime.h>
#include <linux/netdevice.h>
#include "base.h"
#include "power/power.h"
@ -1843,15 +1844,60 @@ void device_shutdown(void)
*/
#ifdef CONFIG_PRINTK
int __dev_printk(const char *level, const struct device *dev,
struct va_format *vaf)
{
char dict[128];
size_t dictlen = 0;
const char *subsys;
if (!dev)
return printk("%s(NULL device *): %pV", level, vaf);
return printk("%s%s %s: %pV",
level, dev_driver_string(dev), dev_name(dev), vaf);
if (dev->class)
subsys = dev->class->name;
else if (dev->bus)
subsys = dev->bus->name;
else
goto skip;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
"SUBSYSTEM=%s", subsys);
/*
* Add device identifier DEVICE=:
* b12:8 block dev_t
* c127:3 char dev_t
* n8 netdev ifindex
* +sound:card0 subsystem:devname
*/
if (MAJOR(dev->devt)) {
char c;
if (strcmp(subsys, "block") == 0)
c = 'b';
else
c = 'c';
dictlen++;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
"DEVICE=%c%u:%u",
c, MAJOR(dev->devt), MINOR(dev->devt));
} else if (strcmp(subsys, "net") == 0) {
struct net_device *net = to_net_dev(dev);
dictlen++;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
"DEVICE=n%u", net->ifindex);
} else {
dictlen++;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
"DEVICE=+%s:%s", subsys, dev_name(dev));
}
skip:
return printk_emit(0, level[1] - '0',
dictlen ? dict : NULL, dictlen,
"%s %s: %pV",
dev_driver_string(dev), dev_name(dev), vaf);
}
EXPORT_SYMBOL(__dev_printk);