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dev_dbg/dynamic_debug: Update to use printk_emit, optimize stack 

commit c4e00daaa9
("driver-core: extend dev_printk() to pass structured data")
changed __dev_printk and broke dynamic-debug's ability to control the
dynamic prefix of dev_dbg(dev,..).

commit af7f2158fd
("drivers-core: make structured logging play nice with dynamic-debug")
made a minimal correction.

The current dynamic debug code uses up to 3 recursion levels via %pV.
This can consume quite a bit of stack.  Directly call printk_emit to
reduce the recursion depth.

These changes include:

dev_dbg:
o Create and use function create_syslog_header to format the syslog
  header for printk_emit uses.
o Call create_syslog_header and neaten __dev_printk
o Make __dev_printk static not global
o Remove include header declaration of __dev_printk
o Remove now unused EXPORT_SYMBOL() of __dev_printk
o Whitespace neatening

dynamic_dev_dbg:
o Remove KERN_DEBUG from dynamic_emit_prefix
o Call create_syslog_header and printk_emit
o Whitespace neatening

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Joe Perches 2012-09-12 20:11:29 -07:00 committed by Greg Kroah-Hartman
parent 8f949b9a7e
commit 798efc60e4
3 changed files with 67 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
drivers/base/core.c
View File

@ -1865,26 +1865,19 @@ void device_shutdown(void)
*/
#ifdef CONFIG_PRINTK
int __dev_printk(const char *level, const struct device *dev,
struct va_format *vaf)
int create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
{
char dict[128];
const char *level_extra = "";
size_t dictlen = 0;
const char *subsys;
if (!dev)
return printk("%s(NULL device *): %pV", level, vaf);
size_t pos = 0;
if (dev->class)
subsys = dev->class->name;
else if (dev->bus)
subsys = dev->bus->name;
else
goto skip;
return 0;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
"SUBSYSTEM=%s", subsys);
pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
/*
* Add device identifier DEVICE=:
@ -1900,32 +1893,41 @@ int __dev_printk(const char *level, const struct device *dev,
c = 'b';
else
c = 'c';
dictlen++;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
pos++;
pos += snprintf(hdr + pos, hdrlen - pos,
"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,
pos++;
pos += snprintf(hdr + pos, hdrlen - pos,
"DEVICE=n%u", net->ifindex);
} else {
dictlen++;
dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
pos++;
pos += snprintf(hdr + pos, hdrlen - pos,
"DEVICE=+%s:%s", subsys, dev_name(dev));
}
skip:
if (level[2])
level_extra = &level[2]; /* skip past KERN_SOH "L" */
return printk_emit(0, level[1] - '0',
dictlen ? dict : NULL, dictlen,
"%s %s: %s%pV",
dev_driver_string(dev), dev_name(dev),
level_extra, vaf);
return pos;
}
EXPORT_SYMBOL(create_syslog_header);
static int __dev_printk(const char *level, const struct device *dev,
struct va_format *vaf)
{
char hdr[128];
size_t hdrlen;
if (!dev)
return printk("%s(NULL device *): %pV", level, vaf);
hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
return printk_emit(0, level[1] - '0', hdrlen ? hdr : NULL, hdrlen,
"%s %s: %pV",
dev_driver_string(dev), dev_name(dev), vaf);
}
EXPORT_SYMBOL(__dev_printk);
int dev_printk(const char *level, const struct device *dev,
const char *fmt, ...)
@ -1940,6 +1942,7 @@ int dev_printk(const char *level, const struct device *dev,
vaf.va = &args;
r = __dev_printk(level, dev, &vaf);
va_end(args);
return r;
@ -1959,6 +1962,7 @@ int func(const struct device *dev, const char *fmt, ...) \
vaf.va = &args; \
\
r = __dev_printk(kern_level, dev, &vaf); \
\
va_end(args); \
\
return r; \

8
include/linux/device.h
View File

@ -895,12 +895,12 @@ extern const char *dev_driver_string(const struct device *dev);
#ifdef CONFIG_PRINTK
extern int __dev_printk(const char *level, const struct device *dev,
struct va_format *vaf);
extern int create_syslog_header(const struct device *dev,
char *hdr, size_t hdrlen);
extern __printf(3, 4)
int dev_printk(const char *level, const struct device *dev,
const char *fmt, ...)
;
const char *fmt, ...);
extern __printf(2, 3)
int dev_emerg(const struct device *dev, const char *fmt, ...);
extern __printf(2, 3)

31
lib/dynamic_debug.c
View File

@ -521,11 +521,11 @@ static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
int pos_after_tid;
int pos = 0;
pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
*buf = '\0';
if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
if (in_interrupt())
pos += snprintf(buf + pos, remaining(pos), "%s ",
"<intr>");
pos += snprintf(buf + pos, remaining(pos), "<intr> ");
else
pos += snprintf(buf + pos, remaining(pos), "[%d] ",
task_pid_vnr(current));
@ -559,9 +559,13 @@ int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
BUG_ON(!fmt);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
res = printk(KERN_DEBUG "%s%pV",
dynamic_emit_prefix(descriptor, buf), &vaf);
va_end(args);
return res;
@ -574,15 +578,30 @@ int __dynamic_dev_dbg(struct _ddebug *descriptor,
struct va_format vaf;
va_list args;
int res;
char buf[PREFIX_SIZE];
BUG_ON(!descriptor);
BUG_ON(!fmt);
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
if (!dev) {
res = printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
} else {
char buf[PREFIX_SIZE];
char dict[128];
size_t dictlen;
dictlen = create_syslog_header(dev, dict, sizeof(dict));
res = printk_emit(0, 7, dictlen ? dict : NULL, dictlen,
"%s%s %s: %pV",
dynamic_emit_prefix(descriptor, buf),
dev_driver_string(dev), dev_name(dev), &vaf);
}
va_end(args);
return res;