DMI: allow omitting ident strings in DMI tables

The purpose of dmi->ident is twofold - it may be used by DMI callback
functions when composing log messages; it is also used to determine
end of DMI table in dmi_check_system() and dmi_first_match(). However,
in case when callbacks are not interested in using ident at all it just
wastes memory. Let's make entries with empty first match slot serve as
end-of-table markers instead.

Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 938100f..3a2ccb0 100644 (file)
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -429,7 +429,7 @@ static bool dmi_matches(const struct dmi_system_id *dmi)
        for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
                int s = dmi->matches[i].slot;
                if (s == DMI_NONE)
-                       continue;
+                       break;
                if (dmi_ident[s]
                    && strstr(dmi_ident[s], dmi->matches[i].substr))
                        continue;
@@ -439,6 +439,15 @@ static bool dmi_matches(const struct dmi_system_id *dmi)
        return true;
 }
 
+/**
+ *     dmi_is_end_of_table - check for end-of-table marker
+ *     @dmi: pointer to the dmi_system_id structure to check
+ */
+static bool dmi_is_end_of_table(const struct dmi_system_id *dmi)
+{
+       return dmi->matches[0].slot == DMI_NONE;
+}
+
 /**
  *     dmi_check_system - check system DMI data
  *     @list: array of dmi_system_id structures to match against
@@ -457,7 +466,7 @@ int dmi_check_system(const struct dmi_system_id *list)
        int count = 0;
        const struct dmi_system_id *d;
 
-       for (d = list; d->ident; d++)
+       for (d = list; !dmi_is_end_of_table(d); d++)
                if (dmi_matches(d)) {
                        count++;
                        if (d->callback && d->callback(d))
@@ -484,7 +493,7 @@ const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
 {
        const struct dmi_system_id *d;
 
-       for (d = list; d->ident; d++)
+       for (d = list; !dmi_is_end_of_table(d); d++)
                if (dmi_matches(d))
                        return d;