[PATCH] libata: add per-dev pio/mwdma/udma_mask

Add per-dev pio/mwdma/udma_mask.  All transfer mode limits used to be
applied to ap->*_mask which unnecessarily restricted other devices
sharing the port.  This change will also benefit later EH speed down
and hotplug.

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

2 files changed, 30 insertions, 18 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 1514cb5e35f7..a87748ba579c 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -65,8 +65,7 @@ static unsigned int ata_dev_init_params(struct ata_port *ap,
                                         struct ata_device *dev);
 static void ata_set_mode(struct ata_port *ap);
 static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev);
-static unsigned int ata_dev_xfermask(struct ata_port *ap,
-                                     struct ata_device *dev);
+static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev);
 
 static unsigned int ata_unique_id = 1;
 static struct workqueue_struct *ata_wq;
@@ -1801,16 +1800,19 @@ static void ata_set_mode(struct ata_port *ap)
         /* step 1: calculate xfer_mask */
         for (i = 0; i < ATA_MAX_DEVICES; i++) {
                 struct ata_device *dev = &ap->device[i];
-                unsigned int xfer_mask;
+                unsigned int pio_mask, dma_mask;
 
                 if (!ata_dev_present(dev))
                         continue;
 
-                xfer_mask = ata_dev_xfermask(ap, dev);
+                ata_dev_xfermask(ap, dev);
 
-                dev->pio_mode = ata_xfer_mask2mode(xfer_mask & ATA_MASK_PIO);
-                dev->dma_mode = ata_xfer_mask2mode(xfer_mask & (ATA_MASK_MWDMA |
-                                                                ATA_MASK_UDMA));
+                /* TODO: let LLDD filter dev->*_mask here */
+
+                pio_mask = ata_pack_xfermask(dev->pio_mask, 0, 0);
+                dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
+                dev->pio_mode = ata_xfer_mask2mode(pio_mask);
+                dev->dma_mode = ata_xfer_mask2mode(dma_mask);
         }
 
         /* step 2: always set host PIO timings */
@@ -2653,18 +2655,15 @@ static int ata_dma_blacklisted(const struct ata_device *dev)
  *      @ap: Port on which the device to compute xfermask for resides
  *      @dev: Device to compute xfermask for
  *
- *      Compute supported xfermask of @dev.  This function is
- *      responsible for applying all known limits including host
- *      controller limits, device blacklist, etc...
+ *      Compute supported xfermask of @dev and store it in
+ *      dev->*_mask.  This function is responsible for applying all
+ *      known limits including host controller limits, device
+ *      blacklist, etc...
  *
  *      LOCKING:
  *      None.
- *
- *      RETURNS:
- *      Computed xfermask.
  */
-static unsigned int ata_dev_xfermask(struct ata_port *ap,
-                                     struct ata_device *dev)
+static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev)
 {
         unsigned long xfer_mask;
         int i;
@@ -2677,6 +2676,8 @@ static unsigned int ata_dev_xfermask(struct ata_port *ap,
                 struct ata_device *d = &ap->device[i];
                 if (!ata_dev_present(d))
                         continue;
+                xfer_mask &= ata_pack_xfermask(d->pio_mask, d->mwdma_mask,
+                                               d->udma_mask);
                 xfer_mask &= ata_id_xfermask(d->id);
                 if (ata_dma_blacklisted(d))
                         xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
@@ -2686,7 +2687,8 @@ static unsigned int ata_dev_xfermask(struct ata_port *ap,
                 printk(KERN_WARNING "ata%u: dev %u is on DMA blacklist, "
                        "disabling DMA\n", ap->id, dev->devno);
 
-        return xfer_mask;
+        ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
+                            &dev->udma_mask);
 }
 
 /**
@@ -4436,8 +4438,13 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
         INIT_WORK(&ap->port_task, NULL, NULL);
         INIT_LIST_HEAD(&ap->eh_done_q);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                ap->device[i].devno = i;
+        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+                struct ata_device *dev = &ap->device[i];
+                dev->devno = i;
+                dev->pio_mask = UINT_MAX;
+                dev->mwdma_mask = UINT_MAX;
+                dev->udma_mask = UINT_MAX;
+        }
 
 #ifdef ATA_IRQ_TRAP
         ap->stats.unhandled_irq = 1;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 7a54244d30aa..fbe8ba212598 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -358,6 +358,11 @@ struct ata_device {
         unsigned int            max_sectors;    /* per-device max sectors */
         unsigned int            cdb_len;
 
+        /* per-dev xfer mask */
+        unsigned int            pio_mask;
+        unsigned int            mwdma_mask;
+        unsigned int            udma_mask;
+
         /* for CHS addressing */
         u16                     cylinders;      /* Number of cylinders */
         u16                     heads;          /* Number of heads */