2 files changed, 82 insertions, 9 deletions

diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt
index 3f429ed8b3b8..e9f9e767f82a 100644
--- a/Documentation/kbuild/kconfig.txt
+++ b/Documentation/kbuild/kconfig.txt
@@ -174,6 +174,19 @@ Searching in menuconfig:
 
                 /^hotplug
 
+        When searching, symbols are sorted thus:
+          - exact match first: an exact match is when the search matches
+            the complete symbol name;
+          - alphabetical order: when two symbols do not match exactly,
+            they are sorted in alphabetical order (in the user's current
+            locale).
+        For example: ^ATH.K matches:
+            ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
+            [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
+        of which only ATH5K and ATH9K match exactly and so are sorted
+        first (and in alphabetical order), then come all other symbols,
+        sorted in alphabetical order.
+
 ______________________________________________________________________
 User interface options for 'menuconfig'
 
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index ab8f4c835933..387d55483882 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -954,38 +954,98 @@ const char *sym_escape_string_value(const char *in)
         return res;
 }
 
+struct sym_match {
+        struct symbol   *sym;
+        off_t           so, eo;
+};
+
+/* Compare matched symbols as thus:
+ * - first, symbols that match exactly
+ * - then, alphabetical sort
+ */
+static int sym_rel_comp( const void *sym1, const void *sym2 )
+{
+        struct sym_match *s1 = *(struct sym_match **)sym1;
+        struct sym_match *s2 = *(struct sym_match **)sym2;
+        int l1, l2;
+
+        /* Exact match:
+         * - if matched length on symbol s1 is the length of that symbol,
+         *   then this symbol should come first;
+         * - if matched length on symbol s2 is the length of that symbol,
+         *   then this symbol should come first.
+         * Note: since the search can be a regexp, both symbols may match
+         * exactly; if this is the case, we can't decide which comes first,
+         * and we fallback to sorting alphabetically.
+         */
+        l1 = s1->eo - s1->so;
+        l2 = s2->eo - s2->so;
+        if (l1 == strlen(s1->sym->name) && l2 != strlen(s2->sym->name))
+                return -1;
+        if (l1 != strlen(s1->sym->name) && l2 == strlen(s2->sym->name))
+                return 1;
+
+        /* As a fallback, sort symbols alphabetically */
+        return strcmp(s1->sym->name, s2->sym->name);
+}
+
 struct symbol **sym_re_search(const char *pattern)
 {
         struct symbol *sym, **sym_arr = NULL;
+        struct sym_match **sym_match_arr = NULL;
         int i, cnt, size;
         regex_t re;
+        regmatch_t match[1];
 
         cnt = size = 0;
         /* Skip if empty */
         if (strlen(pattern) == 0)
                 return NULL;
-        if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB|REG_ICASE))
+        if (regcomp(&re, pattern, REG_EXTENDED|REG_ICASE))
                 return NULL;
 
         for_all_symbols(i, sym) {
+                struct sym_match *tmp_sym_match;
                 if (sym->flags & SYMBOL_CONST || !sym->name)
                         continue;
-                if (regexec(&re, sym->name, 0, NULL, 0))
+                if (regexec(&re, sym->name, 1, match, 0))
                         continue;
                 if (cnt + 1 >= size) {
-                        void *tmp = sym_arr;
+                        void *tmp;
                         size += 16;
-                        sym_arr = realloc(sym_arr, size * sizeof(struct symbol *));
-                        if (!sym_arr) {
-                                free(tmp);
-                                return NULL;
+                        tmp = realloc(sym_match_arr, size * sizeof(struct sym_match *));
+                        if (!tmp) {
+                                goto sym_re_search_free;
                         }
+                        sym_match_arr = tmp;
                 }
                 sym_calc_value(sym);
-                sym_arr[cnt++] = sym;
+                tmp_sym_match = (struct sym_match*)malloc(sizeof(struct sym_match));
+                if (!tmp_sym_match)
+                        goto sym_re_search_free;
+                tmp_sym_match->sym = sym;
+                /* As regexec return 0, we know we have a match, so
+                 * we can use match[0].rm_[se]o without further checks
+                 */
+                tmp_sym_match->so = match[0].rm_so;
+                tmp_sym_match->eo = match[0].rm_eo;
+                sym_match_arr[cnt++] = tmp_sym_match;
         }
-        if (sym_arr)
+        if (sym_match_arr) {
+                qsort(sym_match_arr, cnt, sizeof(struct sym_match*), sym_rel_comp);
+                sym_arr = malloc((cnt+1) * sizeof(struct symbol));
+                if (!sym_arr)
+                        goto sym_re_search_free;
+                for (i = 0; i < cnt; i++)
+                        sym_arr[i] = sym_match_arr[i]->sym;
                 sym_arr[cnt] = NULL;
+        }
+sym_re_search_free:
+        if (sym_match_arr) {
+                for (i = 0; i < cnt; i++)
+                        free(sym_match_arr[i]);
+                free(sym_match_arr);
+        }
         regfree(&re);
 
         return sym_arr;