EDAC: Fixup scrubrate manipulation

Make the ->{get|set}_sdram_scrub_rate return the actual scrub rate
bandwidth it succeeded setting and remove superfluous arg pointer used
for that. A negative value returned still means that an error occurred
while setting the scrubrate. Document this for future reference.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

1 files changed, 28 insertions, 29 deletions

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index dce61f7ba38b..39d97cfdf58c 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -436,56 +436,55 @@ static ssize_t mci_reset_counters_store(struct mem_ctl_info *mci,
         return count;
 }
 
-/* memory scrubbing */
+/* Memory scrubbing interface:
+ *
+ * A MC driver can limit the scrubbing bandwidth based on the CPU type.
+ * Therefore, ->set_sdram_scrub_rate should be made to return the actual
+ * bandwidth that is accepted or 0 when scrubbing is to be disabled.
+ *
+ * Negative value still means that an error has occurred while setting
+ * the scrub rate.
+ */
 static ssize_t mci_sdram_scrub_rate_store(struct mem_ctl_info *mci,
                                           const char *data, size_t count)
 {
         unsigned long bandwidth = 0;
-        int err;
+        int new_bw = 0;
 
-        if (!mci->set_sdram_scrub_rate) {
-                edac_printk(KERN_WARNING, EDAC_MC,
-                            "Memory scrub rate setting not implemented!\n");
+        if (!mci->set_sdram_scrub_rate)
                 return -EINVAL;
-        }
 
         if (strict_strtoul(data, 10, &bandwidth) < 0)
                 return -EINVAL;
 
-        err = mci->set_sdram_scrub_rate(mci, (u32)bandwidth);
-        if (err) {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Failed setting scrub rate to %lu\n", bandwidth);
-                return -EINVAL;
-        }
-        else {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Scrub rate set to: %lu\n", bandwidth);
+        new_bw = mci->set_sdram_scrub_rate(mci, bandwidth);
+        if (new_bw >= 0) {
+                edac_printk(KERN_DEBUG, EDAC_MC, "Scrub rate set to %d\n", new_bw);
                 return count;
         }
+
+        edac_printk(KERN_DEBUG, EDAC_MC, "Error setting scrub rate to: %lu\n", bandwidth);
+        return -EINVAL;
 }
 
+/*
+ * ->get_sdram_scrub_rate() return value semantics same as above.
+ */
 static ssize_t mci_sdram_scrub_rate_show(struct mem_ctl_info *mci, char *data)
 {
-        u32 bandwidth = 0;
-        int err;
+        int bandwidth = 0;
 
-        if (!mci->get_sdram_scrub_rate) {
-                edac_printk(KERN_WARNING, EDAC_MC,
-                            "Memory scrub rate reading not implemented\n");
+        if (!mci->get_sdram_scrub_rate)
                 return -EINVAL;
-        }
 
-        err = mci->get_sdram_scrub_rate(mci, &bandwidth);
-        if (err) {
+        bandwidth = mci->get_sdram_scrub_rate(mci);
+        if (bandwidth < 0) {
                 edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n");
-                return err;
-        }
-        else {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Read scrub rate: %d\n", bandwidth);
-                return sprintf(data, "%d\n", bandwidth);
+                return bandwidth;
         }
+
+        edac_printk(KERN_DEBUG, EDAC_MC, "Read scrub rate: %d\n", bandwidth);
+        return sprintf(data, "%d\n", bandwidth);
 }
 
 /* default attribute files for the MCI object */