Commit 8cf4e6a0 authored Feb 03, 2018 by Jean Delvare

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
  d7b1956f ("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: d7b1956f ("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>

parent d8a5b805

drivers/firmware/dmi_scan.c

+11 −8

Original line number	Diff line number	Diff line
		@@ -784,20 +784,21 @@ 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))
		if (dmi->matches[i].exact_match) {
		if (!strcmp(dmi_ident[s],
		dmi->matches[i].substr))
		continue;
		else if (dmi->matches[i].exact_match &&
		!strcmp(dmi_ident[s], dmi->matches[i].substr))
		} else {
		if (strstr(dmi_ident[s],
		dmi->matches[i].substr))
		continue;
		}
		}

		/* No match */
		return false;
		@@ -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++;