dyndbg: combine flags & mask into a struct, simplify with it

flags & mask are used together everywhere, and are passed around
together between multiple functions; they belong together in a struct,
call that struct flag_settings.

Use struct flag_settings to rework 3 functions:
 - ddebug_exec_query - declares query and flag-settings,
   		     calls other 2, passing flags
 - ddebug_parse_flags - fills flag_settings and returns
 - ddebug_change - test all callsites against query,
   		   modify passing sites.

benefits:
 - bit-banging always needs flags & mask, best together.
 - simpler function signatures
 - 1 less parameter, less stack overhead

no functional changes

Acked-by: <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200719231058.1586423-16-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index fad6c34..c983049 100644 (file)
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -62,6 +62,11 @@ struct ddebug_iter {
        unsigned int idx;
 };
 
+struct flag_settings {
+       unsigned int flags;
+       unsigned int mask;
+};
+
 static DEFINE_MUTEX(ddebug_lock);
 static LIST_HEAD(ddebug_tables);
 static int verbose;
@@ -141,7 +146,7 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
  * logs the changes.  Takes ddebug_lock.
  */
 static int ddebug_change(const struct ddebug_query *query,
-                       unsigned int flags, unsigned int mask)
+                        struct flag_settings *modifiers)
 {
        int i;
        struct ddebug_table *dt;
@@ -190,14 +195,14 @@ static int ddebug_change(const struct ddebug_query *query,
 
                        nfound++;
 
-                       newflags = (dp->flags & mask) | flags;
+                       newflags = (dp->flags & modifiers->mask) | modifiers->flags;
                        if (newflags == dp->flags)
                                continue;
 #ifdef CONFIG_JUMP_LABEL
                        if (dp->flags & _DPRINTK_FLAGS_PRINT) {
-                               if (!(flags & _DPRINTK_FLAGS_PRINT))
+                               if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT))
                                        static_branch_disable(&dp->key.dd_key_true);
-                       } else if (flags & _DPRINTK_FLAGS_PRINT)
+                       } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT)
                                static_branch_enable(&dp->key.dd_key_true);
 #endif
                        dp->flags = newflags;
@@ -431,11 +436,9 @@ static int ddebug_parse_query(char *words[], int nwords,
  * 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)
+static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 {
-       unsigned flags = 0;
-       int op = '=', i;
+       int op, i;
 
        switch (*str) {
        case '+':
@@ -452,7 +455,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
        for (; *str ; ++str) {
                for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
                        if (*str == opt_array[i].opt_char) {
-                               flags |= opt_array[i].flag;
+                               modifiers->flags |= opt_array[i].flag;
                                break;
                        }
                }
@@ -461,30 +464,30 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
                        return -EINVAL;
                }
        }
-       vpr_info("flags=0x%x\n", flags);
+       vpr_info("flags=0x%x\n", modifiers->flags);
 
-       /* calculate final *flagsp, *maskp according to mask and op */
+       /* calculate final flags, mask based upon op */
        switch (op) {
        case '=':
-               *maskp = 0;
-               *flagsp = flags;
+               /* modifiers->flags already set */
+               modifiers->mask = 0;
                break;
        case '+':
-               *maskp = ~0U;
-               *flagsp = flags;
+               modifiers->mask = ~0U;
                break;
        case '-':
-               *maskp = ~flags;
-               *flagsp = 0;
+               modifiers->mask = ~modifiers->flags;
+               modifiers->flags = 0;
                break;
        }
-       vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+       vpr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);
+
        return 0;
 }
 
 static int ddebug_exec_query(char *query_string, const char *modname)
 {
-       unsigned int flags = 0, mask = 0;
+       struct flag_settings modifiers = {};
        struct ddebug_query query = {};
 #define MAXWORDS 9
        int nwords, nfound;
@@ -496,7 +499,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
                return -EINVAL;
        }
        /* check flags 1st (last arg) so query is pairs of spec,val */
-       if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) {
+       if (ddebug_parse_flags(words[nwords-1], &modifiers)) {
                pr_err("flags parse failed\n");
                return -EINVAL;
        }
@@ -505,7 +508,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
                return -EINVAL;
        }
        /* actually go and implement the change */
-       nfound = ddebug_change(&query, flags, mask);
+       nfound = ddebug_change(&query, &modifiers);
        vpr_info_dq(&query, nfound ? "applied" : "no-match");
 
        return nfound;