linux/lib/dynamic_debug.c

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/*
* lib/dynamic_debug.c
*
* make pr_debug()/dev_dbg() calls runtime configurable based upon their
* source module.
*
* Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
* By Greg Banks <gnb@melbourne.sgi.com>
* Copyright (c) 2008 Silicon Graphics Inc. All Rights Reserved.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/list.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/dynamic_debug.h>
#include <linux/debugfs.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
extern struct _ddebug __start___verbose[];
extern struct _ddebug __stop___verbose[];
/* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which
* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
* use independent hash functions, to reduce the chance of false positives.
*/
long long dynamic_debug_enabled;
EXPORT_SYMBOL_GPL(dynamic_debug_enabled);
long long dynamic_debug_enabled2;
EXPORT_SYMBOL_GPL(dynamic_debug_enabled2);
struct ddebug_table {
struct list_head link;
char *mod_name;
unsigned int num_ddebugs;
unsigned int num_enabled;
struct _ddebug *ddebugs;
};
struct ddebug_query {
const char *filename;
const char *module;
const char *function;
const char *format;
unsigned int first_lineno, last_lineno;
};
struct ddebug_iter {
struct ddebug_table *table;
unsigned int idx;
};
static DEFINE_MUTEX(ddebug_lock);
static LIST_HEAD(ddebug_tables);
static int verbose = 0;
/* Return the last part of a pathname */
static inline const char *basename(const char *path)
{
const char *tail = strrchr(path, '/');
return tail ? tail+1 : path;
}
/* format a string into buf[] which describes the _ddebug's flags */
static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
size_t maxlen)
{
char *p = buf;
BUG_ON(maxlen < 4);
if (dp->flags & _DPRINTK_FLAGS_PRINT)
*p++ = 'p';
if (p == buf)
*p++ = '-';
*p = '\0';
return buf;
}
/*
* must be called with ddebug_lock held
*/
static int disabled_hash(char hash, bool first_table)
{
struct ddebug_table *dt;
char table_hash_value;
list_for_each_entry(dt, &ddebug_tables, link) {
if (first_table)
table_hash_value = dt->ddebugs->primary_hash;
else
table_hash_value = dt->ddebugs->secondary_hash;
if (dt->num_enabled && (hash == table_hash_value))
return 0;
}
return 1;
}
/*
* Search the tables for _ddebug's which match the given
* `query' and apply the `flags' and `mask' to them. Tells
* the user which ddebug's were changed, or whether none
* were matched.
*/
static void ddebug_change(const struct ddebug_query *query,
unsigned int flags, unsigned int mask)
{
int i;
struct ddebug_table *dt;
unsigned int newflags;
unsigned int nfound = 0;
char flagbuf[8];
/* search for matching ddebugs */
mutex_lock(&ddebug_lock);
list_for_each_entry(dt, &ddebug_tables, link) {
/* match against the module name */
if (query->module != NULL &&
strcmp(query->module, dt->mod_name))
continue;
for (i = 0 ; i < dt->num_ddebugs ; i++) {
struct _ddebug *dp = &dt->ddebugs[i];
/* match against the source filename */
if (query->filename != NULL &&
strcmp(query->filename, dp->filename) &&
strcmp(query->filename, basename(dp->filename)))
continue;
/* match against the function */
if (query->function != NULL &&
strcmp(query->function, dp->function))
continue;
/* match against the format */
if (query->format != NULL &&
strstr(dp->format, query->format) == NULL)
continue;
/* match against the line number range */
if (query->first_lineno &&
dp->lineno < query->first_lineno)
continue;
if (query->last_lineno &&
dp->lineno > query->last_lineno)
continue;
nfound++;
newflags = (dp->flags & mask) | flags;
if (newflags == dp->flags)
continue;
if (!newflags)
dt->num_enabled--;
else if (!dp->flags)
dt->num_enabled++;
dp->flags = newflags;
if (newflags) {
dynamic_debug_enabled |=
(1LL << dp->primary_hash);
dynamic_debug_enabled2 |=
(1LL << dp->secondary_hash);
} else {
if (disabled_hash(dp->primary_hash, true))
dynamic_debug_enabled &=
~(1LL << dp->primary_hash);
if (disabled_hash(dp->secondary_hash, false))
dynamic_debug_enabled2 &=
~(1LL << dp->secondary_hash);
}
if (verbose)
printk(KERN_INFO
"ddebug: changed %s:%d [%s]%s %s\n",
dp->filename, dp->lineno,
dt->mod_name, dp->function,
ddebug_describe_flags(dp, flagbuf,
sizeof(flagbuf)));
}
}
mutex_unlock(&ddebug_lock);
if (!nfound && verbose)
printk(KERN_INFO "ddebug: no matches for query\n");
}
/*
* Split the buffer `buf' into space-separated words.
* Handles simple " and ' quoting, i.e. without nested,
* embedded or escaped \". Return the number of words
* or <0 on error.
*/
static int ddebug_tokenize(char *buf, char *words[], int maxwords)
{
int nwords = 0;
while (*buf) {
char *end;
/* Skip leading whitespace */
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
buf = skip_spaces(buf);
if (!*buf)
break; /* oh, it was trailing whitespace */
/* Run `end' over a word, either whitespace separated or quoted */
if (*buf == '"' || *buf == '\'') {
int quote = *buf++;
for (end = buf ; *end && *end != quote ; end++)
;
if (!*end)
return -EINVAL; /* unclosed quote */
} else {
for (end = buf ; *end && !isspace(*end) ; end++)
;
BUG_ON(end == buf);
}
/* Here `buf' is the start of the word, `end' is one past the end */
if (nwords == maxwords)
return -EINVAL; /* ran out of words[] before bytes */
if (*end)
*end++ = '\0'; /* terminate the word */
words[nwords++] = buf;
buf = end;
}
if (verbose) {
int i;
printk(KERN_INFO "%s: split into words:", __func__);
for (i = 0 ; i < nwords ; i++)
printk(" \"%s\"", words[i]);
printk("\n");
}
return nwords;
}
/*
* Parse a single line number. Note that the empty string ""
* is treated as a special case and converted to zero, which
* is later treated as a "don't care" value.
*/
static inline int parse_lineno(const char *str, unsigned int *val)
{
char *end = NULL;
BUG_ON(str == NULL);
if (*str == '\0') {
*val = 0;
return 0;
}
*val = simple_strtoul(str, &end, 10);
return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
}
/*
* Undo octal escaping in a string, inplace. This is useful to
* allow the user to express a query which matches a format
* containing embedded spaces.
*/
#define isodigit(c) ((c) >= '0' && (c) <= '7')
static char *unescape(char *str)
{
char *in = str;
char *out = str;
while (*in) {
if (*in == '\\') {
if (in[1] == '\\') {
*out++ = '\\';
in += 2;
continue;
} else if (in[1] == 't') {
*out++ = '\t';
in += 2;
continue;
} else if (in[1] == 'n') {
*out++ = '\n';
in += 2;
continue;
} else if (isodigit(in[1]) &&
isodigit(in[2]) &&
isodigit(in[3])) {
*out++ = ((in[1] - '0')<<6) |
((in[2] - '0')<<3) |
(in[3] - '0');
in += 4;
continue;
}
}
*out++ = *in++;
}
*out = '\0';
return str;
}
/*
* Parse words[] as a ddebug query specification, which is a series
* of (keyword, value) pairs chosen from these possibilities:
*
* func <function-name>
* file <full-pathname>
* file <base-filename>
* module <module-name>
* format <escaped-string-to-find-in-format>
* line <lineno>
* line <first-lineno>-<last-lineno> // where either may be empty
*/
static int ddebug_parse_query(char *words[], int nwords,
struct ddebug_query *query)
{
unsigned int i;
/* check we have an even number of words */
if (nwords % 2 != 0)
return -EINVAL;
memset(query, 0, sizeof(*query));
for (i = 0 ; i < nwords ; i += 2) {
if (!strcmp(words[i], "func"))
query->function = words[i+1];
else if (!strcmp(words[i], "file"))
query->filename = words[i+1];
else if (!strcmp(words[i], "module"))
query->module = words[i+1];
else if (!strcmp(words[i], "format"))
query->format = unescape(words[i+1]);
else if (!strcmp(words[i], "line")) {
char *first = words[i+1];
char *last = strchr(first, '-');
if (last)
*last++ = '\0';
if (parse_lineno(first, &query->first_lineno) < 0)
return -EINVAL;
if (last != NULL) {
/* range <first>-<last> */
if (parse_lineno(last, &query->last_lineno) < 0)
return -EINVAL;
} else {
query->last_lineno = query->first_lineno;
}
} else {
if (verbose)
printk(KERN_ERR "%s: unknown keyword \"%s\"\n",
__func__, words[i]);
return -EINVAL;
}
}
if (verbose)
printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" "
"q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
__func__, query->function, query->filename,
query->module, query->format, query->first_lineno,
query->last_lineno);
return 0;
}
/*
* Parse `str' as a flags specification, format [-+=][p]+.
* Sets up *maskp and *flagsp to be used when changing the
* flags fields of matched _ddebug's. Returns 0 on success
* or <0 on error.
*/
static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
unsigned int *maskp)
{
unsigned flags = 0;
int op = '=';
switch (*str) {
case '+':
case '-':
case '=':
op = *str++;
break;
default:
return -EINVAL;
}
if (verbose)
printk(KERN_INFO "%s: op='%c'\n", __func__, op);
for ( ; *str ; ++str) {
switch (*str) {
case 'p':
flags |= _DPRINTK_FLAGS_PRINT;
break;
default:
return -EINVAL;
}
}
if (flags == 0)
return -EINVAL;
if (verbose)
printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags);
/* calculate final *flagsp, *maskp according to mask and op */
switch (op) {
case '=':
*maskp = 0;
*flagsp = flags;
break;
case '+':
*maskp = ~0U;
*flagsp = flags;
break;
case '-':
*maskp = ~flags;
*flagsp = 0;
break;
}
if (verbose)
printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n",
__func__, *flagsp, *maskp);
return 0;
}
/*
* File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
* command text from userspace, parses and executes it.
*/
static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
size_t len, loff_t *offp)
{
unsigned int flags = 0, mask = 0;
struct ddebug_query query;
#define MAXWORDS 9
int nwords;
char *words[MAXWORDS];
char tmpbuf[256];
if (len == 0)
return 0;
/* we don't check *offp -- multiple writes() are allowed */
if (len > sizeof(tmpbuf)-1)
return -E2BIG;
if (copy_from_user(tmpbuf, ubuf, len))
return -EFAULT;
tmpbuf[len] = '\0';
if (verbose)
printk(KERN_INFO "%s: read %d bytes from userspace\n",
__func__, (int)len);
nwords = ddebug_tokenize(tmpbuf, words, MAXWORDS);
if (nwords < 0)
return -EINVAL;
if (ddebug_parse_query(words, nwords-1, &query))
return -EINVAL;
if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
return -EINVAL;
/* actually go and implement the change */
ddebug_change(&query, flags, mask);
*offp += len;
return len;
}
/*
* Set the iterator to point to the first _ddebug object
* and return a pointer to that first object. Returns
* NULL if there are no _ddebugs at all.
*/
static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
{
if (list_empty(&ddebug_tables)) {
iter->table = NULL;
iter->idx = 0;
return NULL;
}
iter->table = list_entry(ddebug_tables.next,
struct ddebug_table, link);
iter->idx = 0;
return &iter->table->ddebugs[iter->idx];
}
/*
* Advance the iterator to point to the next _ddebug
* object from the one the iterator currently points at,
* and returns a pointer to the new _ddebug. Returns
* NULL if the iterator has seen all the _ddebugs.
*/
static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
{
if (iter->table == NULL)
return NULL;
if (++iter->idx == iter->table->num_ddebugs) {
/* iterate to next table */
iter->idx = 0;
if (list_is_last(&iter->table->link, &ddebug_tables)) {
iter->table = NULL;
return NULL;
}
iter->table = list_entry(iter->table->link.next,
struct ddebug_table, link);
}
return &iter->table->ddebugs[iter->idx];
}
/*
* Seq_ops start method. Called at the start of every
* read() call from userspace. Takes the ddebug_lock and
* seeks the seq_file's iterator to the given position.
*/
static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
{
struct ddebug_iter *iter = m->private;
struct _ddebug *dp;
int n = *pos;
if (verbose)
printk(KERN_INFO "%s: called m=%p *pos=%lld\n",
__func__, m, (unsigned long long)*pos);
mutex_lock(&ddebug_lock);
if (!n)
return SEQ_START_TOKEN;
if (n < 0)
return NULL;
dp = ddebug_iter_first(iter);
while (dp != NULL && --n > 0)
dp = ddebug_iter_next(iter);
return dp;
}
/*
* Seq_ops next method. Called several times within a read()
* call from userspace, with ddebug_lock held. Walks to the
* next _ddebug object with a special case for the header line.
*/
static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
{
struct ddebug_iter *iter = m->private;
struct _ddebug *dp;
if (verbose)
printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n",
__func__, m, p, (unsigned long long)*pos);
if (p == SEQ_START_TOKEN)
dp = ddebug_iter_first(iter);
else
dp = ddebug_iter_next(iter);
++*pos;
return dp;
}
/*
* Seq_ops show method. Called several times within a read()
* call from userspace, with ddebug_lock held. Formats the
* current _ddebug as a single human-readable line, with a
* special case for the header line.
*/
static int ddebug_proc_show(struct seq_file *m, void *p)
{
struct ddebug_iter *iter = m->private;
struct _ddebug *dp = p;
char flagsbuf[8];
if (verbose)
printk(KERN_INFO "%s: called m=%p p=%p\n",
__func__, m, p);
if (p == SEQ_START_TOKEN) {
seq_puts(m,
"# filename:lineno [module]function flags format\n");
return 0;
}
seq_printf(m, "%s:%u [%s]%s %s \"",
dp->filename, dp->lineno,
iter->table->mod_name, dp->function,
ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
seq_escape(m, dp->format, "\t\r\n\"");
seq_puts(m, "\"\n");
return 0;
}
/*
* Seq_ops stop method. Called at the end of each read()
* call from userspace. Drops ddebug_lock.
*/
static void ddebug_proc_stop(struct seq_file *m, void *p)
{
if (verbose)
printk(KERN_INFO "%s: called m=%p p=%p\n",
__func__, m, p);
mutex_unlock(&ddebug_lock);
}
static const struct seq_operations ddebug_proc_seqops = {
.start = ddebug_proc_start,
.next = ddebug_proc_next,
.show = ddebug_proc_show,
.stop = ddebug_proc_stop
};
/*
* File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
* setup dance, and also creates an iterator to walk the _ddebugs.
* Note that we create a seq_file always, even for O_WRONLY files
* where it's not needed, as doing so simplifies the ->release method.
*/
static int ddebug_proc_open(struct inode *inode, struct file *file)
{
struct ddebug_iter *iter;
int err;
if (verbose)
printk(KERN_INFO "%s: called\n", __func__);
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (iter == NULL)
return -ENOMEM;
err = seq_open(file, &ddebug_proc_seqops);
if (err) {
kfree(iter);
return err;
}
((struct seq_file *) file->private_data)->private = iter;
return 0;
}
static const struct file_operations ddebug_proc_fops = {
.owner = THIS_MODULE,
.open = ddebug_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
.write = ddebug_proc_write
};
/*
* Allocate a new ddebug_table for the given module
* and add it to the global list.
*/
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *name)
{
struct ddebug_table *dt;
char *new_name;
dt = kzalloc(sizeof(*dt), GFP_KERNEL);
if (dt == NULL)
return -ENOMEM;
new_name = kstrdup(name, GFP_KERNEL);
if (new_name == NULL) {
kfree(dt);
return -ENOMEM;
}
dt->mod_name = new_name;
dt->num_ddebugs = n;
dt->num_enabled = 0;
dt->ddebugs = tab;
mutex_lock(&ddebug_lock);
list_add_tail(&dt->link, &ddebug_tables);
mutex_unlock(&ddebug_lock);
if (verbose)
printk(KERN_INFO "%u debug prints in module %s\n",
n, dt->mod_name);
return 0;
}
EXPORT_SYMBOL_GPL(ddebug_add_module);
static void ddebug_table_free(struct ddebug_table *dt)
{
list_del_init(&dt->link);
kfree(dt->mod_name);
kfree(dt);
}
/*
* Called in response to a module being unloaded. Removes
* any ddebug_table's which point at the module.
*/
int ddebug_remove_module(char *mod_name)
{
struct ddebug_table *dt, *nextdt;
int ret = -ENOENT;
if (verbose)
printk(KERN_INFO "%s: removing module \"%s\"\n",
__func__, mod_name);
mutex_lock(&ddebug_lock);
list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
if (!strcmp(dt->mod_name, mod_name)) {
ddebug_table_free(dt);
ret = 0;
}
}
mutex_unlock(&ddebug_lock);
return ret;
}
EXPORT_SYMBOL_GPL(ddebug_remove_module);
static void ddebug_remove_all_tables(void)
{
mutex_lock(&ddebug_lock);
while (!list_empty(&ddebug_tables)) {
struct ddebug_table *dt = list_entry(ddebug_tables.next,
struct ddebug_table,
link);
ddebug_table_free(dt);
}
mutex_unlock(&ddebug_lock);
}
static int __init dynamic_debug_init(void)
{
struct dentry *dir, *file;
struct _ddebug *iter, *iter_start;
const char *modname = NULL;
int ret = 0;
int n = 0;
dir = debugfs_create_dir("dynamic_debug", NULL);
if (!dir)
return -ENOMEM;
file = debugfs_create_file("control", 0644, dir, NULL,
&ddebug_proc_fops);
if (!file) {
debugfs_remove(dir);
return -ENOMEM;
}
if (__start___verbose != __stop___verbose) {
iter = __start___verbose;
modname = iter->modname;
iter_start = iter;
for (; iter < __stop___verbose; iter++) {
if (strcmp(modname, iter->modname)) {
ret = ddebug_add_module(iter_start, n, modname);
if (ret)
goto out_free;
n = 0;
modname = iter->modname;
iter_start = iter;
}
n++;
}
ret = ddebug_add_module(iter_start, n, modname);
}
out_free:
if (ret) {
ddebug_remove_all_tables();
debugfs_remove(dir);
debugfs_remove(file);
}
return 0;
}
module_init(dynamic_debug_init);