10 files changed, 21 insertions, 220 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 29e71bddd6ff..3c06e457b4dc 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1975,16 +1975,11 @@ static int ahci_port_start(struct ata_port *ap)
         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)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index a109ccbda9ca..3587ac3fe3f3 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4493,30 +4493,13 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
         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;
@@ -4767,97 +4750,6 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
         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.
@@ -4874,26 +4766,17 @@ static unsigned int ata_sg_setup_extra(struct ata_queued_cmd *qc,
 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;
@@ -5962,9 +5845,6 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
          */
         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))
@@ -6573,19 +6453,12 @@ void ata_host_resume(struct ata_host *host)
 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;
 }
 
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 1cea18f62abc..6e15c5ddae6d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -832,24 +832,16 @@ static void ata_scsi_dev_config(struct scsi_device *sdev,
         /* 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);
@@ -2500,7 +2492,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
          * 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
@@ -3555,7 +3547,7 @@ EXPORT_SYMBOL_GPL(ata_sas_port_alloc);
  *      @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.
  *
@@ -3564,7 +3556,7 @@ EXPORT_SYMBOL_GPL(ata_sas_port_alloc);
  */
 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);
 
@@ -3572,8 +3564,6 @@ 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:
@@ -3582,7 +3572,6 @@ EXPORT_SYMBOL_GPL(ata_sas_port_start);
 
 void ata_sas_port_stop(struct ata_port *ap)
 {
-        ata_pad_free(ap, ap->dev);
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_stop);
 
diff --git a/drivers/ata/pata_icside.c b/drivers/ata/pata_icside.c
index 5b8586dac63b..f97068be2d79 100644
--- a/drivers/ata/pata_icside.c
+++ b/drivers/ata/pata_icside.c
@@ -304,12 +304,6 @@ static int icside_dma_init(struct pata_icside_info *info)
 }
 
 
-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,
@@ -389,8 +383,6 @@ static struct ata_port_operations pata_icside_port_ops = {
         .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,
 };
diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index efcb66b6ccef..9323dd0c7d8d 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -601,21 +601,9 @@ static int sata_fsl_port_start(struct ata_port *ap)
         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;
         }
@@ -694,7 +682,6 @@ static void sata_fsl_port_stop(struct ata_port *ap)
         dma_free_coherent(dev, SATA_FSL_PORT_PRIV_DMA_SZ,
                           pp->cmdslot, pp->cmdslot_paddr);
 
-        ata_pad_free(ap, dev);
         kfree(pp);
 }
 
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 2ecd44db4142..1c1fbf375d9a 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -1158,17 +1158,13 @@ static int mv_port_start(struct ata_port *ap)
         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;
diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index b4b1f91ea693..df7988df7908 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -1234,7 +1234,6 @@ static int sil24_port_start(struct ata_port *ap)
         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)
@@ -1247,10 +1246,6 @@ static int sil24_port_start(struct ata_port *ap)
                 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;
 
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 2074701f7e76..c72014a3e7d4 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -5140,7 +5140,7 @@ static void ipr_build_ata_ioadl(struct ipr_cmnd *ipr_cmd,
         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;
 
@@ -5206,7 +5206,7 @@ static unsigned int ipr_qc_issue(struct ata_queued_cmd *qc)
         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;
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 0996f866f14c..7cd05b599a12 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -178,8 +178,8 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
         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;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index bc5a8d0c7090..2e098f940cec 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -278,7 +278,6 @@ enum {
 
         /* 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,
@@ -457,24 +456,18 @@ struct ata_queued_cmd {
         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;
 
@@ -619,9 +612,6 @@ struct ata_port {
         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 */
@@ -1363,12 +1353,9 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
         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);
@@ -1423,19 +1410,6 @@ static inline unsigned int __ac_err_mask(u8 status)
         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];