fprobe: Resolve symbols with ftrace_lookup_symbols

Using ftrace_lookup_symbols to speed up symbols lookup
in register_fprobe_syms API.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 89d9f99..aac63ca 100644 (file)
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -85,39 +85,31 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,
 }
 NOKPROBE_SYMBOL(fprobe_exit_handler);
 
+static int symbols_cmp(const void *a, const void *b)
+{
+       const char **str_a = (const char **) a;
+       const char **str_b = (const char **) b;
+
+       return strcmp(*str_a, *str_b);
+}
+
 /* Convert ftrace location address from symbols */
 static unsigned long *get_ftrace_locations(const char **syms, int num)
 {
-       unsigned long addr, size;
        unsigned long *addrs;
-       int i;
 
        /* Convert symbols to symbol address */
        addrs = kcalloc(num, sizeof(*addrs), GFP_KERNEL);
        if (!addrs)
                return ERR_PTR(-ENOMEM);
 
-       for (i = 0; i < num; i++) {
-               addr = kallsyms_lookup_name(syms[i]);
-               if (!addr)      /* Maybe wrong symbol */
-                       goto error;
-
-               /* Convert symbol address to ftrace location. */
-               if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
-                       goto error;
+       /* ftrace_lookup_symbols expects sorted symbols */
+       sort(syms, num, sizeof(*syms), symbols_cmp, NULL);
 
-               addr = ftrace_location_range(addr, addr + size - 1);
-               if (!addr) /* No dynamic ftrace there. */
-                       goto error;
+       if (!ftrace_lookup_symbols(syms, num, addrs))
+               return addrs;
 
-               addrs[i] = addr;
-       }
-
-       return addrs;
-
-error:
        kfree(addrs);
-
        return ERR_PTR(-ENOENT);
 }