firmware: dmi: Optimize dmi_matches

Function dmi_matches can me made a bit faster:

* The documented purpose of dmi_initialized is to catch too early
  calls to dmi_check_system(). I'm not fully convinced it justifies
  slowing down the initialization of all systems out there, but at
  least the check should not have been moved from dmi_check_system()
  to dmi_matches(). dmi_matches() is being called for every entry of
  the table passed to dmi_check_system(), causing the same redundant
  check to be performed again and again. So move it back to
  dmi_check_system(), reverting this specific portion of commit
  d7b1956fed33 ("DMI: Introduce dmi_first_match to make the interface
  more flexible").

* Don't check for the exact_match flag again when we already know its
  value.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: d7b1956fed33 ("DMI: Introduce dmi_first_match to make the interface more flexible")
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Jeff Garzik <jgarzik@redhat.com>

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 7830419..84356d8 100644 (file)
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -784,19 +784,20 @@ static bool dmi_matches(const struct dmi_system_id *dmi)
 {
        int i;
 
-       WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");
-
        for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
                int s = dmi->matches[i].slot;
                if (s == DMI_NONE)
                        break;
                if (dmi_ident[s]) {
-                       if (!dmi->matches[i].exact_match &&
-                           strstr(dmi_ident[s], dmi->matches[i].substr))
-                               continue;
-                       else if (dmi->matches[i].exact_match &&
-                                !strcmp(dmi_ident[s], dmi->matches[i].substr))
-                               continue;
+                       if (dmi->matches[i].exact_match) {
+                               if (!strcmp(dmi_ident[s],
+                                           dmi->matches[i].substr))
+                                       continue;
+                       } else {
+                               if (strstr(dmi_ident[s],
+                                          dmi->matches[i].substr))
+                                       continue;
+                       }
                }
 
                /* No match */
@@ -832,6 +833,8 @@ int dmi_check_system(const struct dmi_system_id *list)
        int count = 0;
        const struct dmi_system_id *d;
 
+       WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");
+
        for (d = list; !dmi_is_end_of_table(d); d++)
                if (dmi_matches(d)) {
                        count++;