This allow users to invert the selection of any keyword.
For example:

  echo "module !virtio* +p" > /proc/dynamic_debug/control

When I test with virtme-ng, this cmd prevents flooding the logs with
virtio activity.  Its not perfect, because it cannot also avoid
flooding from pr_debugs in serial_core or other potential sources.

A more robust command is:

  echo "module !virtio* +p % module serial -p" > /proc/dynamic_debug/control

Signed-off-by: Jim Cromie <[email protected]>
---
 lib/dynamic_debug.c | 76 +++++++++++++++++++++++++++++++--------------
 1 file changed, 53 insertions(+), 23 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 80fa8d2143e8..a283d12fd64d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -59,6 +59,10 @@ struct ddebug_query {
        const char *format;
        const char *class_string;
        unsigned int first_lineno, last_lineno;
+       unsigned int filename_neg:1;
+       unsigned int module_neg:1;
+       unsigned int function_neg:1;
+       unsigned int format_neg:1;
 };
 
 struct ddebug_iter {
@@ -163,11 +167,12 @@ static void vpr_info_dq(const struct ddebug_query *query, 
const char *msg)
                        fmtlen--;
        }
 
-       v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" 
lineno=%u-%u class=%s\n",
+       v3pr_info("%s: func%s=\"%s\" file%s=\"%s\" module%s=\"%s\" 
format%s=\"%.*s\" lineno=%u-%u class=%s\n",
                  msg,
-                 query->function ?: "",
-                 query->filename ?: "",
-                 query->module ?: "",
+                 query->function_neg ? "!" : "", query->function ?: "",
+                 query->filename_neg ? "!" : "", query->filename ?: "",
+                 query->module_neg ? "!" : "", query->module ?: "",
+                 query->format_neg ? "!" : "",
                  fmtlen, query->format ?: "",
                  query->first_lineno, query->last_lineno, query->class_string);
 }
@@ -268,32 +273,34 @@ static bool ddebug_match_desc(const struct ddebug_query 
*query,
                              int selected_class)
 {
        struct _ddebug_class_map *site_map;
+       bool match;
 
        /* match against the source filename */
-       if (query->filename &&
-           !match_wildcard(query->filename, dp->filename) &&
-           !match_wildcard(query->filename,
-                           kbasename(dp->filename)) &&
-           !match_wildcard(query->filename,
-                           trim_prefix(dp->filename)))
-               return false;
+       if (query->filename) {
+               match = match_wildcard(query->filename, dp->filename) ||
+                       match_wildcard(query->filename, 
kbasename(dp->filename)) ||
+                       match_wildcard(query->filename, 
trim_prefix(dp->filename));
+               if (match == query->filename_neg)
+                       return false;
+       }
 
        /* match against the function */
-       if (query->function &&
-           !match_wildcard(query->function, dp->function))
-               return false;
+       if (query->function) {
+               match = match_wildcard(query->function, dp->function);
+               if (match == query->function_neg)
+                       return false;
+       }
 
        /* match against the format */
        if (query->format) {
                if (*query->format == '^') {
-                       char *p;
                        /* anchored search. match must be at beginning */
-                       p = strstr(dp->format, query->format + 1);
-                       if (p != dp->format)
-                               return false;
-               } else if (!strstr(dp->format, query->format)) {
-                       return false;
+                       match = (strstr(dp->format, query->format + 1) == 
dp->format);
+               } else {
+                       match = !!strstr(dp->format, query->format);
                }
+               if (match == query->format_neg)
+                       return false;
        }
 
        /* match against the line number range */
@@ -345,9 +352,11 @@ static int ddebug_change(const struct ddebug_query *query, 
struct flag_settings
                struct _ddebug_class_map *mods_map;
 
                /* match against the module name */
-               if (query->module &&
-                   !match_wildcard(query->module, di->mod_name))
-                       continue;
+               if (query->module) {
+                       bool match = match_wildcard(query->module, 
di->mod_name);
+                       if (match == query->module_neg)
+                               continue;
+               }
 
                selected_class = _DPRINTK_CLASS_DFLT;
                if (query->class_string) {
@@ -514,6 +523,16 @@ static int parse_linerange(struct ddebug_query *query, 
const char *first)
        return 0;
 }
 
+static char *check_neg(char *src, unsigned int *neg)
+{
+       if (*src == '!') {
+               *neg = 1;
+               return src + 1;
+       }
+       *neg = 0;
+       return src;
+}
+
 static int check_set(const char **dest, char *src, char *name)
 {
        int rc = 0;
@@ -558,10 +577,15 @@ static int ddebug_parse_query(char *words[], int nwords,
        for (i = 0; i < nwords; i += 2) {
                char *keyword = words[i];
                char *arg = words[i+1];
+               unsigned int neg;
 
                if (!strcmp(keyword, "func")) {
+                       arg = check_neg(arg, &neg);
+                       query->function_neg = neg;
                        rc = check_set(&query->function, arg, "func");
                } else if (!strcmp(keyword, "file")) {
+                       arg = check_neg(arg, &neg);
+                       query->filename_neg = neg;
                        if (check_set(&query->filename, arg, "file"))
                                return -EINVAL;
 
@@ -572,6 +596,8 @@ static int ddebug_parse_query(char *words[], int nwords,
                        *fline++ = '\0';
                        if (isalpha(*fline) || *fline == '*' || *fline == '?') {
                                /* take as function name */
+                               fline = check_neg(fline, &neg);
+                               query->function_neg = neg;
                                if (check_set(&query->function, fline, "func"))
                                        return -EINVAL;
                        } else {
@@ -579,11 +605,15 @@ static int ddebug_parse_query(char *words[], int nwords,
                                        return -EINVAL;
                        }
                } else if (!strcmp(keyword, "module")) {
+                       arg = check_neg(arg, &neg);
+                       query->module_neg = neg;
                        rc = check_set(&query->module, arg, "module");
                } else if (!strcmp(keyword, "format")) {
                        string_unescape_inplace(arg, UNESCAPE_SPACE |
                                                            UNESCAPE_OCTAL |
                                                            UNESCAPE_SPECIAL);
+                       arg = check_neg(arg, &neg);
+                       query->format_neg = neg;
                        rc = check_set(&query->format, arg, "format");
                } else if (!strcmp(keyword, "line")) {
                        if (parse_linerange(query, arg))
-- 
2.53.0

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