sata_nv: Use notifier for completion checks

The hardware provides us a notifier register that indicates what command
tags have completed. Use this to determine which CPBs to check, rather
than blindly checking all active CPBs. This should provide a minor
performance win, since if the controller has touched some of these
incomplete CPBs, accessing them will likely result in a cache miss.

Signed-off-by: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 7 insertions, 15 deletions

diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
index 57dace43b337..745d85686f5e 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -854,22 +854,14 @@ static irqreturn_t nv_adma_interrupt(int irq, void *dev_instance)
 
                         if (status & (NV_ADMA_STAT_DONE |
                                       NV_ADMA_STAT_CPBERR)) {
+                                u32 check_commands = notifier | notifier_error;
+                                int pos, error = 0;
                                 /** Check CPBs for completed commands */
-
-                                if (ata_tag_valid(ap->active_tag)) {
-                                        /* Non-NCQ command */
-                                        nv_adma_check_cpb(ap, ap->active_tag,
-                                                notifier_error & (1 << ap->active_tag));
-                                } else {
-                                        int pos, error = 0;
-                                        u32 active = ap->sactive;
-
-                                        while ((pos = ffs(active)) && !error) {
-                                                pos--;
-                                                error = nv_adma_check_cpb(ap, pos,
-                                                        notifier_error & (1 << pos) );
-                                                active &= ~(1 << pos );
-                                        }
+                                while ((pos = ffs(check_commands)) && !error) {
+                                        pos--;
+                                        error = nv_adma_check_cpb(ap, pos,
+                                                notifier_error & (1 << pos) );
+                                        check_commands &= ~(1 << pos );
                                 }
                         }
                 }