struct ahci_port_priv *pp;
        void *mem;
        dma_addr_t mem_dma;
-       int rc;
 
        pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
        if (!pp)
                return -ENOMEM;
 
-       rc = ata_pad_alloc(ap, dev);
-       if (rc)
-               return rc;
-
        mem = dmam_alloc_coherent(dev, AHCI_PORT_PRIV_DMA_SZ, &mem_dma,
                                  GFP_KERNEL);
        if (!mem)
 
        struct ata_port *ap = qc->ap;
        struct scatterlist *sg = qc->sg;
        int dir = qc->dma_dir;
-       void *pad_buf = NULL;
 
        WARN_ON(sg == NULL);
 
-       VPRINTK("unmapping %u sg elements\n", qc->mapped_n_elem);
+       VPRINTK("unmapping %u sg elements\n", qc->n_elem);
 
-       /* if we padded the buffer out to 32-bit bound, and data
-        * xfer direction is from-device, we must copy from the
-        * pad buffer back into the supplied buffer
-        */
-       if (qc->pad_len && !(qc->tf.flags & ATA_TFLAG_WRITE))
-               pad_buf = ap->pad + (qc->tag * ATA_DMA_PAD_SZ);
-
-       if (qc->mapped_n_elem)
-               dma_unmap_sg(ap->dev, sg, qc->mapped_n_elem, dir);
-       /* restore last sg */
-       if (qc->last_sg)
-               *qc->last_sg = qc->saved_last_sg;
-       if (pad_buf) {
-               struct scatterlist *psg = &qc->extra_sg[1];
-               void *addr = kmap_atomic(sg_page(psg), KM_IRQ0);
-               memcpy(addr + psg->offset, pad_buf, qc->pad_len);
-               kunmap_atomic(addr, KM_IRQ0);
-       }
+       if (qc->n_elem)
+               dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);
 
        qc->flags &= ~ATA_QCFLAG_DMAMAP;
        qc->sg = NULL;
        qc->cursg = qc->sg;
 }
 
-static unsigned int ata_sg_setup_extra(struct ata_queued_cmd *qc,
-                                      unsigned int *n_elem_extra,
-                                      unsigned int *nbytes_extra)
-{
-       struct ata_port *ap = qc->ap;
-       unsigned int n_elem = qc->n_elem;
-       struct scatterlist *lsg, *copy_lsg = NULL, *tsg = NULL, *esg = NULL;
-
-       *n_elem_extra = 0;
-       *nbytes_extra = 0;
-
-       /* needs padding? */
-       qc->pad_len = qc->nbytes & 3;
-
-       if (likely(!qc->pad_len))
-               return n_elem;
-
-       /* locate last sg and save it */
-       lsg = sg_last(qc->sg, n_elem);
-       qc->last_sg = lsg;
-       qc->saved_last_sg = *lsg;
-
-       sg_init_table(qc->extra_sg, ARRAY_SIZE(qc->extra_sg));
-
-       if (qc->pad_len) {
-               struct scatterlist *psg = &qc->extra_sg[1];
-               void *pad_buf = ap->pad + (qc->tag * ATA_DMA_PAD_SZ);
-               unsigned int offset;
-
-               WARN_ON(qc->dev->class != ATA_DEV_ATAPI);
-
-               memset(pad_buf, 0, ATA_DMA_PAD_SZ);
-
-               /* psg->page/offset are used to copy to-be-written
-                * data in this function or read data in ata_sg_clean.
-                */
-               offset = lsg->offset + lsg->length - qc->pad_len;
-               sg_set_page(psg, nth_page(sg_page(lsg), offset >> PAGE_SHIFT),
-                           qc->pad_len, offset_in_page(offset));
-
-               if (qc->tf.flags & ATA_TFLAG_WRITE) {
-                       void *addr = kmap_atomic(sg_page(psg), KM_IRQ0);
-                       memcpy(pad_buf, addr + psg->offset, qc->pad_len);
-                       kunmap_atomic(addr, KM_IRQ0);
-               }
-
-               sg_dma_address(psg) = ap->pad_dma + (qc->tag * ATA_DMA_PAD_SZ);
-               sg_dma_len(psg) = ATA_DMA_PAD_SZ;
-
-               /* Trim the last sg entry and chain the original and
-                * padding sg lists.
-                *
-                * Because chaining consumes one sg entry, one extra
-                * sg entry is allocated and the last sg entry is
-                * copied to it if the length isn't zero after padded
-                * amount is removed.
-                *
-                * If the last sg entry is completely replaced by
-                * padding sg entry, the first sg entry is skipped
-                * while chaining.
-                */
-               lsg->length -= qc->pad_len;
-               if (lsg->length) {
-                       copy_lsg = &qc->extra_sg[0];
-                       tsg = &qc->extra_sg[0];
-               } else {
-                       n_elem--;
-                       tsg = &qc->extra_sg[1];
-               }
-
-               esg = &qc->extra_sg[1];
-
-               (*n_elem_extra)++;
-               (*nbytes_extra) += 4 - qc->pad_len;
-       }
-
-       if (copy_lsg)
-               sg_set_page(copy_lsg, sg_page(lsg), lsg->length, lsg->offset);
-
-       sg_chain(lsg, 1, tsg);
-       sg_mark_end(esg);
-
-       /* sglist can't start with chaining sg entry, fast forward */
-       if (qc->sg == lsg) {
-               qc->sg = tsg;
-               qc->cursg = tsg;
-       }
-
-       return n_elem;
-}
-
 /**
  *     ata_sg_setup - DMA-map the scatter-gather table associated with a command.
  *     @qc: Command with scatter-gather table to be mapped.
 static int ata_sg_setup(struct ata_queued_cmd *qc)
 {
        struct ata_port *ap = qc->ap;
-       unsigned int n_elem, n_elem_extra, nbytes_extra;
+       unsigned int n_elem;
 
        VPRINTK("ENTER, ata%u\n", ap->print_id);
 
-       n_elem = ata_sg_setup_extra(qc, &n_elem_extra, &nbytes_extra);
+       n_elem = dma_map_sg(ap->dev, qc->sg, qc->n_elem, qc->dma_dir);
+       if (n_elem < 1)
+               return -1;
 
-       if (n_elem) {
-               n_elem = dma_map_sg(ap->dev, qc->sg, n_elem, qc->dma_dir);
-               if (n_elem < 1) {
-                       /* restore last sg */
-                       if (qc->last_sg)
-                               *qc->last_sg = qc->saved_last_sg;
-                       return -1;
-               }
-               DPRINTK("%d sg elements mapped\n", n_elem);
-       }
+       DPRINTK("%d sg elements mapped\n", n_elem);
 
-       qc->n_elem = qc->mapped_n_elem = n_elem;
-       qc->n_elem += n_elem_extra;
-       qc->nbytes += nbytes_extra;
+       qc->n_elem = n_elem;
        qc->flags |= ATA_QCFLAG_DMAMAP;
 
        return 0;
         */
        BUG_ON(ata_is_data(prot) && (!qc->sg || !qc->n_elem || !qc->nbytes));
 
-       /* ata_sg_setup() may update nbytes */
-       qc->raw_nbytes = qc->nbytes;
-
        if (ata_is_dma(prot) || (ata_is_pio(prot) &&
                                 (ap->flags & ATA_FLAG_PIO_DMA)))
                if (ata_sg_setup(qc))
 int ata_port_start(struct ata_port *ap)
 {
        struct device *dev = ap->dev;
-       int rc;
 
        ap->prd = dmam_alloc_coherent(dev, ATA_PRD_TBL_SZ, &ap->prd_dma,
                                      GFP_KERNEL);
        if (!ap->prd)
                return -ENOMEM;
 
-       rc = ata_pad_alloc(ap, dev);
-       if (rc)
-               return rc;
-
-       DPRINTK("prd alloc, virt %p, dma %llx\n", ap->prd,
-               (unsigned long long)ap->prd_dma);
        return 0;
 }
 
 
        /* configure max sectors */
        blk_queue_max_sectors(sdev->request_queue, dev->max_sectors);
 
-       /* SATA DMA transfers must be multiples of 4 byte, so
-        * we need to pad ATAPI transfers using an extra sg.
-        * Decrement max hw segments accordingly.
-        */
-       if (dev->class == ATA_DEV_ATAPI) {
-               struct request_queue *q = sdev->request_queue;
-               blk_queue_max_hw_segments(q, q->max_hw_segments - 1);
-
+       if (dev->class == ATA_DEV_ATAPI)
                /* set the min alignment */
                blk_queue_update_dma_alignment(sdev->request_queue,
                                               ATA_DMA_PAD_SZ - 1);
-       } else
+       else {
                /* ATA devices must be sector aligned */
                blk_queue_update_dma_alignment(sdev->request_queue,
                                               ATA_SECT_SIZE - 1);
-
-       if (dev->class == ATA_DEV_ATA)
                sdev->manage_start_stop = 1;
+       }
 
        if (dev->flags & ATA_DFLAG_AN)
                set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);
         * want to set it properly, and for DMA where it is
         * effectively meaningless.
         */
-       nbytes = min(qc->nbytes, (unsigned int)63 * 1024);
+       nbytes = min(scmd->request->raw_data_len, (unsigned int)63 * 1024);
 
        /* Most ATAPI devices which honor transfer chunk size don't
         * behave according to the spec when odd chunk size which
  *     @ap: Port to initialize
  *
  *     Called just after data structures for each port are
- *     initialized.  Allocates DMA pad.
+ *     initialized.
  *
  *     May be used as the port_start() entry in ata_port_operations.
  *
  */
 int ata_sas_port_start(struct ata_port *ap)
 {
-       return ata_pad_alloc(ap, ap->dev);
+       return 0;
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_start);
 
  *     ata_port_stop - Undo ata_sas_port_start()
  *     @ap: Port to shut down
  *
- *     Frees the DMA pad.
- *
  *     May be used as the port_stop() entry in ata_port_operations.
  *
  *     LOCKING:
 
 void ata_sas_port_stop(struct ata_port *ap)
 {
-       ata_pad_free(ap, ap->dev);
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_stop);
 
 
 }
 
 
-static int pata_icside_port_start(struct ata_port *ap)
-{
-       /* No PRD to alloc */
-       return ata_pad_alloc(ap, ap->dev);
-}
-
 static struct scsi_host_template pata_icside_sht = {
        .module                 = THIS_MODULE,
        .name                   = DRV_NAME,
        .irq_clear              = ata_dummy_noret,
        .irq_on                 = ata_irq_on,
 
-       .port_start             = pata_icside_port_start,
-
        .bmdma_stop             = pata_icside_bmdma_stop,
        .bmdma_status           = pata_icside_bmdma_status,
 };
 
        if (!pp)
                return -ENOMEM;
 
-       /*
-        * allocate per command dma alignment pad buffer, which is used
-        * internally by libATA to ensure that all transfers ending on
-        * unaligned boundaries are padded, to align on Dword boundaries
-        */
-       retval = ata_pad_alloc(ap, dev);
-       if (retval) {
-               kfree(pp);
-               return retval;
-       }
-
        mem = dma_alloc_coherent(dev, SATA_FSL_PORT_PRIV_DMA_SZ, &mem_dma,
                                 GFP_KERNEL);
        if (!mem) {
-               ata_pad_free(ap, dev);
                kfree(pp);
                return -ENOMEM;
        }
        dma_free_coherent(dev, SATA_FSL_PORT_PRIV_DMA_SZ,
                          pp->cmdslot, pp->cmdslot_paddr);
 
-       ata_pad_free(ap, dev);
        kfree(pp);
 }
 
 
        struct mv_port_priv *pp;
        void __iomem *port_mmio = mv_ap_base(ap);
        unsigned long flags;
-       int tag, rc;
+       int tag;
 
        pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
        if (!pp)
                return -ENOMEM;
        ap->private_data = pp;
 
-       rc = ata_pad_alloc(ap, dev);
-       if (rc)
-               return rc;
-
        pp->crqb = dma_pool_alloc(hpriv->crqb_pool, GFP_KERNEL, &pp->crqb_dma);
        if (!pp->crqb)
                return -ENOMEM;
 
        union sil24_cmd_block *cb;
        size_t cb_size = sizeof(*cb) * SIL24_MAX_CMDS;
        dma_addr_t cb_dma;
-       int rc;
 
        pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
        if (!pp)
                return -ENOMEM;
        memset(cb, 0, cb_size);
 
-       rc = ata_pad_alloc(ap, dev);
-       if (rc)
-               return rc;
-
        pp->cmd_block = cb;
        pp->cmd_block_dma = cb_dma;
 
 
        struct ipr_ioarcb *ioarcb = &ipr_cmd->ioarcb;
        struct ipr_ioadl_desc *ioadl = ipr_cmd->ioadl;
        struct ipr_ioadl_desc *last_ioadl = NULL;
-       int len = qc->nbytes + qc->pad_len;
+       int len = qc->nbytes;
        struct scatterlist *sg;
        unsigned int si;
 
        ioarcb->cmd_pkt.request_type = IPR_RQTYPE_ATA_PASSTHRU;
        ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_NO_LINK_DESC;
        ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_NO_ULEN_CHK;
-       ipr_cmd->dma_use_sg = qc->pad_len ? qc->n_elem + 1 : qc->n_elem;
+       ipr_cmd->dma_use_sg = qc->n_elem;
 
        ipr_build_ata_ioadl(ipr_cmd, qc);
        regs->flags |= IPR_ATA_FLAG_STATUS_ON_GOOD_COMPLETION;
 
        task->uldd_task = qc;
        if (ata_is_atapi(qc->tf.protocol)) {
                memcpy(task->ata_task.atapi_packet, qc->cdb, qc->dev->cdb_len);
-               task->total_xfer_len = qc->nbytes + qc->pad_len;
-               task->num_scatter = qc->pad_len ? qc->n_elem + 1 : qc->n_elem;
+               task->total_xfer_len = qc->nbytes;
+               task->num_scatter = qc->n_elem;
        } else {
                for_each_sg(qc->sg, sg, qc->n_elem, si)
                        xfer += sg->length;
 
 
        /* size of buffer to pad xfers ending on unaligned boundaries */
        ATA_DMA_PAD_SZ          = 4,
-       ATA_DMA_PAD_BUF_SZ      = ATA_DMA_PAD_SZ * ATA_MAX_QUEUE,
 
        /* ering size */
        ATA_ERING_SIZE          = 32,
        unsigned long           flags;          /* ATA_QCFLAG_xxx */
        unsigned int            tag;
        unsigned int            n_elem;
-       unsigned int            mapped_n_elem;
 
        int                     dma_dir;
 
-       unsigned int            pad_len;
        unsigned int            sect_size;
 
        unsigned int            nbytes;
-       unsigned int            raw_nbytes;
        unsigned int            curbytes;
 
        struct scatterlist      *cursg;
        unsigned int            cursg_ofs;
 
-       struct scatterlist      *last_sg;
-       struct scatterlist      saved_last_sg;
        struct scatterlist      sgent;
-       struct scatterlist      extra_sg[2];
 
        struct scatterlist      *sg;
 
        struct ata_prd          *prd;    /* our SG list */
        dma_addr_t              prd_dma; /* and its DMA mapping */
 
-       void                    *pad;   /* array of DMA pad buffers */
-       dma_addr_t              pad_dma;
-
        struct ata_ioports      ioaddr; /* ATA cmd/ctl/dma register blocks */
 
        u8                      ctl;    /* cache of ATA control register */
        qc->flags = 0;
        qc->cursg = NULL;
        qc->cursg_ofs = 0;
-       qc->nbytes = qc->raw_nbytes = qc->curbytes = 0;
+       qc->nbytes = qc->curbytes = 0;
        qc->n_elem = 0;
-       qc->mapped_n_elem = 0;
        qc->err_mask = 0;
-       qc->pad_len = 0;
-       qc->last_sg = NULL;
        qc->sect_size = ATA_SECT_SIZE;
 
        ata_tf_init(qc->dev, &qc->tf);
        return mask;
 }
 
-static inline int ata_pad_alloc(struct ata_port *ap, struct device *dev)
-{
-       ap->pad_dma = 0;
-       ap->pad = dmam_alloc_coherent(dev, ATA_DMA_PAD_BUF_SZ,
-                                     &ap->pad_dma, GFP_KERNEL);
-       return (ap->pad == NULL) ? -ENOMEM : 0;
-}
-
-static inline void ata_pad_free(struct ata_port *ap, struct device *dev)
-{
-       dmam_free_coherent(dev, ATA_DMA_PAD_BUF_SZ, ap->pad, ap->pad_dma);
-}
-
 static inline struct ata_port *ata_shost_to_port(struct Scsi_Host *host)
 {
        return *(struct ata_port **)&host->hostdata[0];