libata: implement drain buffers

[linux-2.6-omap-h63xx.git] / drivers / ata / libata-core.c

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3587ac3fe3f394bb2e9113672f1d165876ce6a6a..def3682f416a19d04b45893eb172d7f4ecbbbcf0 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4641,28 +4641,6 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
        return 0;
 }
 
-/**
- *     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);