ftrace: Consolidate ftrace_location() and ftrace_text_reserved()

Both ftrace_location() and ftrace_text_reserved() do basically the same thing.
They search to see if an address is in the ftace table (contains an address
that may change from nop to call ftrace_caller). The difference is
that ftrace_location() searches a single address, but ftrace_text_reserved()
searches a range.

This also makes the ftrace_text_reserved() faster as it now uses a bsearch()
instead of linearly searching all the addresses within a page.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fc93562a66541ec114c400813b3e6fb9f166d664..dd091c84b57fed5a70ddcc9dd05a942516342b52 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1383,35 +1383,28 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
 
 static int ftrace_cmp_recs(const void *a, const void *b)
 {
-       const struct dyn_ftrace *reca = a;
-       const struct dyn_ftrace *recb = b;
+       const struct dyn_ftrace *key = a;
+       const struct dyn_ftrace *rec = b;
 
-       if (reca->ip > recb->ip)
-               return 1;
-       if (reca->ip < recb->ip)
+       if (key->flags < rec->ip)
                return -1;
+       if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
+               return 1;
        return 0;
 }
 
-/**
- * ftrace_location - return true if the ip giving is a traced location
- * @ip: the instruction pointer to check
- *
- * Returns 1 if @ip given is a pointer to a ftrace location.
- * That is, the instruction that is either a NOP or call to
- * the function tracer. It checks the ftrace internal tables to
- * determine if the address belongs or not.
- */
-int ftrace_location(unsigned long ip)
+static int ftrace_location_range(unsigned long start, unsigned long end)
 {
        struct ftrace_page *pg;
        struct dyn_ftrace *rec;
        struct dyn_ftrace key;
 
-       key.ip = ip;
+       key.ip = start;
+       key.flags = end;        /* overload flags, as it is unsigned long */
 
        for (pg = ftrace_pages_start; pg; pg = pg->next) {
-               if (ip < pg->records[0].ip || ip > pg->records[pg->index - 1].ip)
+               if (end < pg->records[0].ip ||
+                   start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
                        continue;
                rec = bsearch(&key, pg->records, pg->index,
                              sizeof(struct dyn_ftrace),
@@ -1423,6 +1416,36 @@ int ftrace_location(unsigned long ip)
        return 0;
 }
 
+/**
+ * ftrace_location - return true if the ip giving is a traced location
+ * @ip: the instruction pointer to check
+ *
+ * Returns 1 if @ip given is a pointer to a ftrace location.
+ * That is, the instruction that is either a NOP or call to
+ * the function tracer. It checks the ftrace internal tables to
+ * determine if the address belongs or not.
+ */
+int ftrace_location(unsigned long ip)
+{
+       return ftrace_location_range(ip, ip);
+}
+
+/**
+ * ftrace_text_reserved - return true if range contains an ftrace location
+ * @start: start of range to search
+ * @end: end of range to search (inclusive). @end points to the last byte to check.
+ *
+ * Returns 1 if @start and @end contains a ftrace location.
+ * That is, the instruction that is either a NOP or call to
+ * the function tracer. It checks the ftrace internal tables to
+ * determine if the address belongs or not.
+ */
+int ftrace_text_reserved(void *start, void *end)
+{
+       return ftrace_location_range((unsigned long)start,
+                                    (unsigned long)end);
+}
+
 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
                                     int filter_hash,
                                     bool inc)
@@ -1571,29 +1594,6 @@ void ftrace_bug(int failed, unsigned long ip)
        }
 }
 
-
-/* Return 1 if the address range is reserved for ftrace */
-int ftrace_text_reserved(void *s, void *e)
-{
-       struct dyn_ftrace *rec;
-       struct ftrace_page *pg;
-       unsigned long start = (unsigned long)s;
-       unsigned long end = (unsigned long)e;
-       int i;
-
-       for (pg = ftrace_pages_start; pg; pg = pg->next) {
-               if (end < pg->records[0].ip ||
-                   start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
-                       continue;
-               for (i = 0; i < pg->index; i++) {
-                       rec = &pg->records[i];
-                       if (rec->ip <= end && rec->ip + MCOUNT_INSN_SIZE > start)
-                               return 1;
-               }
-       }
-       return 0;
-}
-
 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
 {
        unsigned long flag = 0UL;