Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  libata: implement drain buffers
  libata: eliminate the home grown dma padding in favour of
  block: clear drain buffer if draining for write command
  block: implement request_queue->dma_drain_needed
  block: add request->raw_data_len
  block: update bio according to DMA alignment padding
  libata: update ATAPI overflow draining
  elevator: make elevator_get() attempt to load the appropriate module
  cfq-iosched: add hlist for browsing parallel to the radix tree
  block: make blk_rq_map_user() clear ->bio if it unmaps it
  fs/block_dev.c: remove #if 0'ed code
  make struct def_blk_aops static
  make blk_settings_init() static
  make blk_ioc_init() static
  make blk-core.c:request_cachep static again

10 files changed, 95 insertions, 279 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 f46eb6f6dc9f..def3682f416a 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;
@@ -4659,43 +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)
-{
-	if (qc->tf.protocol != ATAPI_PROT_PIO &&
-	    qc->tf.protocol != ATAPI_PROT_DMA)
-		return 0;
-
-	if (qc->tf.flags & ATA_TFLAG_WRITE)
-		return 0;
-
-	switch (qc->cdb[0]) {
-	case READ_10:
-	case READ_12:
-	case WRITE_10:
-	case WRITE_12:
-	case GPCMD_READ_CD:
-	case GPCMD_READ_CD_MSF:
-		return 0;
-	}
-
-	return 1;
-}
-
-/**
  *	ata_std_qc_defer - Check whether a qc needs to be deferred
  *	@qc: ATA command in question
  *
@@ -4782,97 +4728,6 @@ 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.
@@ -4889,26 +4744,17 @@ 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;
@@ -5146,46 +4992,22 @@ static void atapi_send_cdb(struct ata_port *ap, struct ata_queued_cmd *qc)
  */
 static int __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
 {
-	int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
+	int rw = (qc->tf.flags & ATA_TFLAG_WRITE) ? WRITE : READ;
 	struct ata_port *ap = qc->ap;
-	struct ata_eh_info *ehi = &qc->dev->link->eh_info;
+	struct ata_device *dev = qc->dev;
+	struct ata_eh_info *ehi = &dev->link->eh_info;
 	struct scatterlist *sg;
 	struct page *page;
 	unsigned char *buf;
-	unsigned int offset, count;
+	unsigned int offset, count, consumed;
 
 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 };
-		unsigned int i;
-
-		if (bytes > qc->curbytes - 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;
-		}
-
-		 /* overflow is exptected for misc ATAPI commands */
-		if (bytes && !atapi_qc_may_overflow(qc))
-			ata_dev_printk(qc->dev, KERN_WARNING, "ATAPI %u bytes "
-				       "trailing data (cdb=%02x nbytes=%u)\n",
-				       bytes, qc->cdb[0], qc->nbytes);
-
-		for (i = 0; i < (bytes + 1) / 2; i++)
-			ap->ops->data_xfer(qc->dev, (unsigned char *)pad_buf, 2, do_write);
-
-		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);
@@ -5211,18 +5033,16 @@ next_sg:
 		buf = kmap_atomic(page, KM_IRQ0);
 
 		/* do the actual data transfer */
-		ap->ops->data_xfer(qc->dev,  buf + offset, count, do_write);
+		consumed = ap->ops->data_xfer(dev,  buf + offset, count, rw);
 
 		kunmap_atomic(buf, KM_IRQ0);
 		local_irq_restore(flags);
 	} else {
 		buf = page_address(page);
-		ap->ops->data_xfer(qc->dev,  buf + offset, count, do_write);
+		consumed = ap->ops->data_xfer(dev,  buf + offset, count, rw);
 	}
 
-	bytes -= count;
-	if ((count & 1) && bytes)
-		bytes--;
+	bytes -= min(bytes, consumed);
 	qc->curbytes += count;
 	qc->cursg_ofs += count;
 
@@ -5231,9 +5051,11 @@ next_sg:
 		qc->cursg_ofs = 0;
 	}
 
+	/* consumed can be larger than count only for the last transfer */
+	WARN_ON(qc->cursg && count != consumed);
+
 	if (bytes)
 		goto next_sg;
-
 	return 0;
 }
 
@@ -5251,6 +5073,7 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 	struct ata_device *dev = qc->dev;
+	struct ata_eh_info *ehi = &dev->link->eh_info;
 	unsigned int ireason, bc_lo, bc_hi, bytes;
 	int i_write, do_write = (qc->tf.flags & ATA_TFLAG_WRITE) ? 1 : 0;
 
@@ -5268,26 +5091,28 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)
 
 	/* shall be cleared to zero, indicating xfer of data */
 	if (unlikely(ireason & (1 << 0)))
-		goto err_out;
+		goto atapi_check;
 
 	/* make sure transfer direction matches expected */
 	i_write = ((ireason & (1 << 1)) == 0) ? 1 : 0;
 	if (unlikely(do_write != i_write))
-		goto err_out;
+		goto atapi_check;
 
 	if (unlikely(!bytes))
-		goto err_out;
+		goto atapi_check;
 
 	VPRINTK("ata%u: xfering %d bytes\n", ap->print_id, bytes);
 
-	if (__atapi_pio_bytes(qc, bytes))
+	if (unlikely(__atapi_pio_bytes(qc, bytes)))
 		goto err_out;
 	ata_altstatus(ap); /* flush */
 
 	return;
 
-err_out:
-	ata_dev_printk(dev, KERN_INFO, "ATAPI check failed\n");
+ atapi_check:
+	ata_ehi_push_desc(ehi, "ATAPI check failed (ireason=0x%x bytes=%u)",
+			  ireason, bytes);
+ err_out:
 	qc->err_mask |= AC_ERR_HSM;
 	ap->hsm_task_state = HSM_ST_ERR;
 }
@@ -5972,9 +5797,6 @@ 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))
@@ -6583,19 +6405,12 @@ 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..dd41b1a1b304 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -826,30 +826,61 @@ 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);
 
-	/* 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);
+		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);
-
-	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);
@@ -861,6 +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;
 }
 
 /**
@@ -879,13 +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;
 }
 
 /**
@@ -905,6 +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;
 
@@ -920,6 +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;
 }
 
 /**
@@ -2500,7 +2539,7 @@ 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 +3594,7 @@ 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 +3603,7 @@ 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 +3611,6 @@ 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 +3619,6 @@ 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/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 135c1d054701..ba21d97d1855 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1014,10 +1014,6 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
 	}
 
 	req->buffer = NULL;
-	if (blk_pc_request(req))
-		sdb->length = req->data_len;
-	else
-		sdb->length = req->nr_sectors << 9;
 
 	/* 
 	 * Next, walk the list, and fill in the addresses and sizes of
@@ -1026,6 +1022,10 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
 	count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
 	BUG_ON(count > sdb->table.nents);
 	sdb->table.nents = count;
+	if (blk_pc_request(req))
+		sdb->length = req->data_len;
+	else
+		sdb->length = req->nr_sectors << 9;
 	return BLKPREP_OK;
 }