[PATCH 13/16] dyndbg: extend ddebug_parse_flags to accept optional leading filter-flags

[Jim Cromie]

change ddebug_parse_flags to accept optional filterflags before OP.
this now sets the parameter added in ~1

Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
 .../admin-guide/dynamic-debug-howto.rst       | 18 +++++++----
 lib/dynamic_debug.c                           | 30 ++++++++++---------
 2 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst 
b/Documentation/admin-guide/dynamic-debug-howto.rst
index 880d33d1782f..250ab30e2080 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -212,13 +212,19 @@ line
        line -1605          // the 1605 lines from line 1 to line 1605
        line 1600-          // all lines from line 1600 to the end of the file
 
-The flags specification comprises a change operation followed
-by one or more flag characters.  The change operation is one
-of the characters::
+Flags Specification::
 
-  -    remove the given flags
-  +    add the given flags
-  =    set the flags to the given flags
+  flagspec     ::= filterflags? OP modflags
+  filterflags  ::= flagset
+  modflags     ::= flagset
+  flagset      ::= ([pfmltu_] | [PFMLTU_])+    # also cant have pP etc
+  OP           ::= [-+=]
+
+OP: modify callsites per following flagset::
+
+  -    remove the following flags
+  +    add the following flags
+  =    set the flags to the following flags
 
 The flags are::
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 32eb7d9545c7..90061833ef3f 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -440,34 +440,36 @@ static int ddebug_read_flags(const char *str, struct 
flagsettings *f)
 }
 
 /*
- * 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.
+ * Parse `str' as a flags-spec, ie: [pfmlt_]*[-+=][pfmlt_]+
+ * Fills flagsettings provided.  Returns 0 on success or <0 on error.
  */
-
 static int ddebug_parse_flags(const char *str,
                              struct flagsettings *mods,
                              struct flagsettings *filter)
 {
        int op;
+       char *opp = strpbrk(str, "-+=");
 
-       switch (*str) {
-       case '+':
-       case '-':
-       case '=':
-               op = *str++;
-               break;
-       default:
-               pr_err("bad flag-op %c, at start of %s\n", *str, str);
+       if (!opp) {
+               pr_err("no OP given in %s\n", str);
                return -EINVAL;
        }
+       op = *opp;
        vpr_info("op='%c'\n", op);
 
+       if (opp != str) {
+               /* filterflags precedes OP, grab it */
+               *opp++ = '\0';
+               if (ddebug_read_flags(str, filter))
+                       return -EINVAL;
+               str = opp;
+       } else
+               str++;
+
        if (ddebug_read_flags(str, mods))
                return -EINVAL;
 
-       /* calculate final flags, mask based upon op */
+       /* calculate final mods: flags, mask based upon op */
        switch (op) {
        case '=':
                mods->mask = 0;
-- 
2.26.2