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Commit 721449bf authored by Robert Hancock's avatar Robert Hancock Committed by Jeff Garzik
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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: default avatarRobert Hancock <hancockr@shaw.ca>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent ac3d6b86

drivers/ata/sata_nv.c

+7 −15
Original line number Diff line number Diff line
@@ -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)) {

				/** 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 {

				u32 check_commands = notifier | notifier_error;

				int pos, error = 0;

					u32 active = ap->sactive;



					while ((pos = ffs(active)) && !error) {

				/** Check CPBs for completed commands */

				while ((pos = ffs(check_commands)) && !error) {

					pos--;

					error = nv_adma_check_cpb(ap, pos,

						notifier_error & (1 << pos) );

						active &= ~(1 << pos );

					}

					check_commands &= ~(1 << pos );

				}

			}

		}