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>
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 91478bd..d325b9d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1865,26 +1865,19 @@
*/
#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 @@
c = 'b';
else
c = 'c';
- dictlen++;
- dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
- "DEVICE=%c%u:%u",
- c, MAJOR(dev->devt), MINOR(dev->devt));
+ 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,
- "DEVICE=n%u", net->ifindex);
+ pos++;
+ pos += snprintf(hdr + pos, hdrlen - pos,
+ "DEVICE=n%u", net->ifindex);
} else {
- dictlen++;
- dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
- "DEVICE=+%s:%s", subsys, dev_name(dev));
+ 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(__dev_printk);
+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);
+}
int dev_printk(const char *level, const struct device *dev,
const char *fmt, ...)
@@ -1940,6 +1942,7 @@
vaf.va = &args;
r = __dev_printk(level, dev, &vaf);
+
va_end(args);
return r;
@@ -1959,6 +1962,7 @@
vaf.va = &args; \
\
r = __dev_printk(kern_level, dev, &vaf); \
+ \
va_end(args); \
\
return r; \