libata: implement ATA_DFLAG_DUBIOUS_XFER

ATA_DFLAG_DUBIOUS_XFER is set whenever data transfer speed or method
changes and gets cleared when data transfer command succeeds in the
newly configured transfer mode.

This will be used to improve speed down logic.

Signed-off-by: Tejun Heo <htejun@gmail.com<
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 86c10cc751e94b2f93b1fa0b9c308f07b179de36..124b6f111cc361958acc1bd7408434637078dc79 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5797,6 +5797,22 @@ static void fill_result_tf(struct ata_queued_cmd *qc)
        ap->ops->tf_read(ap, &qc->result_tf);
 }
 
+static void ata_verify_xfer(struct ata_queued_cmd *qc)
+{
+       struct ata_device *dev = qc->dev;
+
+       if (ata_tag_internal(qc->tag))
+               return;
+
+       if (ata_is_nodata(qc->tf.protocol))
+               return;
+
+       if ((dev->mwdma_mask || dev->udma_mask) && ata_is_pio(qc->tf.protocol))
+               return;
+
+       dev->flags &= ~ATA_DFLAG_DUBIOUS_XFER;
+}
+
 /**
  *     ata_qc_complete - Complete an active ATA command
  *     @qc: Command to complete
@@ -5868,6 +5884,9 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
                        break;
                }
 
+               if (unlikely(dev->flags & ATA_DFLAG_DUBIOUS_XFER))
+                       ata_verify_xfer(qc);
+
                __ata_qc_complete(qc);
        } else {
                if (qc->flags & ATA_QCFLAG_EH_SCHEDULED)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 7d766ada7a5d97cba094f414d9ab815ef485307e..359a5ace84730aeed4193560938c759e35ddb66e 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -456,9 +456,20 @@ void ata_scsi_error(struct Scsi_Host *host)
                spin_lock_irqsave(ap->lock, flags);
 
                __ata_port_for_each_link(link, ap) {
+                       struct ata_eh_context *ehc = &link->eh_context;
+                       struct ata_device *dev;
+
                        memset(&link->eh_context, 0, sizeof(link->eh_context));
                        link->eh_context.i = link->eh_info;
                        memset(&link->eh_info, 0, sizeof(link->eh_info));
+
+                       ata_link_for_each_dev(dev, link) {
+                               int devno = dev->devno;
+
+                               ehc->saved_xfer_mode[devno] = dev->xfer_mode;
+                               if (ata_ncq_enabled(dev))
+                                       ehc->saved_ncq_enabled |= 1 << devno;
+                       }
                }
 
                ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
@@ -2376,11 +2387,27 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 {
        struct ata_port *ap = link->ap;
+       struct ata_device *dev;
+       int rc;
 
        /* has private set_mode? */
        if (ap->ops->set_mode)
-               return ap->ops->set_mode(link, r_failed_dev);
-       return ata_do_set_mode(link, r_failed_dev);
+               rc = ap->ops->set_mode(link, r_failed_dev);
+       else
+               rc = ata_do_set_mode(link, r_failed_dev);
+
+       /* if transfer mode has changed, set DUBIOUS_XFER on device */
+       ata_link_for_each_dev(dev, link) {
+               struct ata_eh_context *ehc = &link->eh_context;
+               u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
+               u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
+
+               if (dev->xfer_mode != saved_xfer_mode ||
+                   ata_ncq_enabled(dev) != saved_ncq)
+                       dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
+       }
+
+       return rc;
 }
 
 static int ata_link_nr_enabled(struct ata_link *link)
@@ -2441,6 +2468,8 @@ static int ata_eh_schedule_probe(struct ata_device *dev)
        ata_dev_init(dev);
        ehc->did_probe_mask |= (1 << dev->devno);
        ehc->i.action |= ATA_EH_SOFTRESET;
+       ehc->saved_xfer_mode[dev->devno] = 0;
+       ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
        return 1;
 }

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 74f1255e252494178cb3ba1b8335fa0e6c800552..131fb6625e142cbfc352240ac15e3887553875e6 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -143,6 +143,7 @@ enum {
        ATA_DFLAG_NCQ_OFF       = (1 << 13), /* device limited to non-NCQ mode */
        ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
        ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
+       ATA_DFLAG_DUBIOUS_XFER  = (1 << 16), /* data transfer not verified */
        ATA_DFLAG_INIT_MASK     = (1 << 24) - 1,
 
        ATA_DFLAG_DETACH        = (1 << 24),
@@ -560,6 +561,8 @@ struct ata_eh_context {
        int                     tries[ATA_MAX_DEVICES];
        unsigned int            classes[ATA_MAX_DEVICES];
        unsigned int            did_probe_mask;
+       unsigned int            saved_ncq_enabled;
+       u8                      saved_xfer_mode[ATA_MAX_DEVICES];
 };
 
 struct ata_acpi_drive