mass_attacher: only log non-attachable kprobes if they pass globs

Instead of logging every BTF FUNC record that doesn't match globs *or*
doesn't have a corresponding attachable kprobes, filter out all the
records that don't satisfy globs first, so that we can log high signal
message about functions that are not attachable, but were requested by
user through globs.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

src/mass_attacher.c

@@ -397,14 +397,20 @@ int mass_attacher__prepare(struct mass_attacher *att)
 		if (!btf_is_func(t))
 			continue;
 
-		/* check if we already processed a function with such name */
+		/* skip BTF function if it doesn't match globs */
 		func_name = btf__str_by_offset(att->vmlinux_btf, t->name_off);
+		if (!glob_set__match(&att->globs, func_name, NULL, NULL))
+			continue;
+
+		/* check if we have a matching attachable kprobe */
 		kp = find_kprobe(att, func_name, NULL);
 		if (!kp) {
-			if (att->debug_extra)
-				printf("Function '%s' is not attachable kprobe, skipping.\n", func_name);
+			if (att->verbose)
+				printf("Function '%s' is not an attachable kprobe, skipping.\n", func_name);
 			continue;
 		}
+
+		/* we might have already processed it, skip if so */
 		if (kp->used)
 			continue;
 
@@ -456,15 +462,23 @@ int mass_attacher__prepare(struct mass_attacher *att)
 			if (!btf_is_func(t))
 				continue;
 
-			/* check if we already processed a function with such name */
+			/* skip BTF function if it doesn't match globs */
 			func_name = btf__str_by_offset(btf, t->name_off);
+			if (!glob_set__match(&att->globs, func_name, mod, NULL))
+				continue;
+
+			/* check if we have a matching attachable kprobe */
 			kp = find_kprobe(att, func_name, mod);
 			if (!kp) {
-				if (att->debug_extra)
-					printf("Function '%s [%s]' is not attachable kprobe, skipping.\n", func_name, mod);
+				if (att->verbose)
+					printf("Function '%s [%s]' is not an attachable kprobe, skipping.\n", func_name, mod);
 				continue;
 			}
 
+			/* we might have already processed it, skip if so */
+			if (kp->used)
+				continue;
+
 			err = prepare_func(att, kp, btf, j);
 			if (err)
 				return err;