2 files changed, 57 insertions, 58 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3587ac3fe3f3..def3682f416a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4642,28 +4642,6 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
 }
 
 /**
- *      atapi_qc_may_overflow - Check whether data transfer may overflow
- *      @qc: ATA command in question
- *
- *      ATAPI commands which transfer variable length data to host
- *      might overflow due to application error or hardare bug.  This
- *      function checks whether overflow should be drained and ignored
- *      for @qc.
- *
- *      LOCKING:
- *      None.
- *
- *      RETURNS:
- *      1 if @qc may overflow; otherwise, 0.
- */
-static int atapi_qc_may_overflow(struct ata_queued_cmd *qc)
-{
-        return ata_is_atapi(qc->tf.protocol) && ata_is_data(qc->tf.protocol) &&
-                atapi_cmd_type(qc->cdb[0]) == ATAPI_MISC &&
-                !(qc->tf.flags & ATA_TFLAG_WRITE);
-}
-
-/**
  *      ata_std_qc_defer - Check whether a qc needs to be deferred
  *      @qc: ATA command in question
  *
@@ -5026,36 +5004,10 @@ static int __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
 next_sg:
         sg = qc->cursg;
         if (unlikely(!sg)) {
-                /*
-                 * The end of qc->sg is reached and the device expects
-                 * more data to transfer. In order not to overrun qc->sg
-                 * and fulfill length specified in the byte count register,
-                 *    - for read case, discard trailing data from the device
-                 *    - for write case, padding zero data to the device
-                 */
-                u16 pad_buf[1] = { 0 };
-
-                if (qc->curbytes + bytes > qc->nbytes + ATAPI_MAX_DRAIN) {
-                        ata_ehi_push_desc(ehi, "too much trailing data "
-                                          "buf=%u cur=%u bytes=%u",
-                                          qc->nbytes, qc->curbytes, bytes);
-                        return -1;
-                }
-
-                /* allow overflow only for misc ATAPI commands */
-                if (!atapi_qc_may_overflow(qc)) {
-                        ata_ehi_push_desc(ehi, "unexpected trailing data "
-                                          "%u bytes", bytes);
-                        return -1;
-                }
-
-                consumed = 0;
-                while (consumed < bytes)
-                        consumed += ap->ops->data_xfer(dev,
-                                        (unsigned char *)pad_buf, 2, rw);
-
-                qc->curbytes += bytes;
-                return 0;
+                ata_ehi_push_desc(ehi, "unexpected or too much trailing data "
+                                  "buf=%u cur=%u bytes=%u",
+                                  qc->nbytes, qc->curbytes, bytes);
+                return -1;
         }
 
         page = sg_page(sg);
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 6e15c5ddae6d..dd41b1a1b304 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -826,17 +826,56 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev)
         sdev->max_device_blocked = 1;
 }
 
-static void ata_scsi_dev_config(struct scsi_device *sdev,
-                                struct ata_device *dev)
+/**
+ *      atapi_drain_needed - Check whether data transfer may overflow
+ *      @request: request to be checked
+ *
+ *      ATAPI commands which transfer variable length data to host
+ *      might overflow due to application error or hardare bug.  This
+ *      function checks whether overflow should be drained and ignored
+ *      for @request.
+ *
+ *      LOCKING:
+ *      None.
+ *
+ *      RETURNS:
+ *      1 if ; otherwise, 0.
+ */
+static int atapi_drain_needed(struct request *rq)
+{
+        if (likely(!blk_pc_request(rq)))
+                return 0;
+
+        if (!rq->data_len || (rq->cmd_flags & REQ_RW))
+                return 0;
+
+        return atapi_cmd_type(rq->cmd[0]) == ATAPI_MISC;
+}
+
+static int ata_scsi_dev_config(struct scsi_device *sdev,
+                               struct ata_device *dev)
 {
         /* configure max sectors */
         blk_queue_max_sectors(sdev->request_queue, dev->max_sectors);
 
-        if (dev->class == ATA_DEV_ATAPI)
+        if (dev->class == ATA_DEV_ATAPI) {
+                struct request_queue *q = sdev->request_queue;
+                void *buf;
+
                 /* set the min alignment */
                 blk_queue_update_dma_alignment(sdev->request_queue,
                                                ATA_DMA_PAD_SZ - 1);
-        else {
+
+                /* configure draining */
+                buf = kmalloc(ATAPI_MAX_DRAIN, q->bounce_gfp | GFP_KERNEL);
+                if (!buf) {
+                        ata_dev_printk(dev, KERN_ERR,
+                                       "drain buffer allocation failed\n");
+                        return -ENOMEM;
+                }
+
+                blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
+        } else {
                 /* ATA devices must be sector aligned */
                 blk_queue_update_dma_alignment(sdev->request_queue,
                                                ATA_SECT_SIZE - 1);
@@ -853,6 +892,8 @@ static void ata_scsi_dev_config(struct scsi_device *sdev,
                 depth = min(ATA_MAX_QUEUE - 1, depth);
                 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
         }
+
+        return 0;
 }
 
 /**
@@ -871,13 +912,14 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 {
         struct ata_port *ap = ata_shost_to_port(sdev->host);
         struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);
+        int rc = 0;
 
         ata_scsi_sdev_config(sdev);
 
         if (dev)
-                ata_scsi_dev_config(sdev, dev);
+                rc = ata_scsi_dev_config(sdev, dev);
 
-        return 0;
+        return rc;
 }
 
 /**
@@ -897,6 +939,7 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 void ata_scsi_slave_destroy(struct scsi_device *sdev)
 {
         struct ata_port *ap = ata_shost_to_port(sdev->host);
+        struct request_queue *q = sdev->request_queue;
         unsigned long flags;
         struct ata_device *dev;
 
@@ -912,6 +955,10 @@ void ata_scsi_slave_destroy(struct scsi_device *sdev)
                 ata_port_schedule_eh(ap);
         }
         spin_unlock_irqrestore(ap->lock, flags);
+
+        kfree(q->dma_drain_buffer);
+        q->dma_drain_buffer = NULL;
+        q->dma_drain_size = 0;
 }
 
 /**