[git patches] fix libata ATAPI DMA alignment

From: Jeff Garzik
Date: Fri Nov 04 2005 - 23:44:46 EST


Please pull from 'upstream-linus' branch of
master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/libata-dev.git

to obtain a fix for SATA ATAPI DMA alignment (xfers must fall on
4-byte boundary).

drivers/scsi/ahci.c | 31 ++++++----
drivers/scsi/libata-core.c | 129 +++++++++++++++++++++++++++++++++++++++------
drivers/scsi/libata-scsi.c | 14 ++++
drivers/scsi/pdc_adma.c | 8 +-
drivers/scsi/sata_mv.c | 48 +++++++++++-----
drivers/scsi/sata_qstor.c | 8 +-
drivers/scsi/sata_sil24.c | 48 +++++++++++-----
drivers/scsi/sata_sx4.c | 13 ++--
include/linux/libata.h | 52 +++++++++++++++++-
9 files changed, 276 insertions(+), 75 deletions(-)

Jeff Garzik:
libata: fix ATAPI DMA alignment issues
libata: add ata_sg_is_last() helper, use it in several drivers
[libata] ATAPI pad allocation fixes/cleanup

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index e2a5657..4612312 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -307,14 +307,22 @@ static int ahci_port_start(struct ata_po
void __iomem *port_mmio = ahci_port_base(mmio, ap->port_no);
void *mem;
dma_addr_t mem_dma;
+ int rc;

pp = kmalloc(sizeof(*pp), GFP_KERNEL);
if (!pp)
return -ENOMEM;
memset(pp, 0, sizeof(*pp));

+ rc = ata_pad_alloc(ap, dev);
+ if (rc) {
+ kfree(pp);
+ return rc;
+ }
+
mem = dma_alloc_coherent(dev, AHCI_PORT_PRIV_DMA_SZ, &mem_dma, GFP_KERNEL);
if (!mem) {
+ ata_pad_free(ap, dev);
kfree(pp);
return -ENOMEM;
}
@@ -390,6 +398,7 @@ static void ahci_port_stop(struct ata_po
ap->private_data = NULL;
dma_free_coherent(dev, AHCI_PORT_PRIV_DMA_SZ,
pp->cmd_slot, pp->cmd_slot_dma);
+ ata_pad_free(ap, dev);
kfree(pp);
}

@@ -468,23 +477,23 @@ static void ahci_tf_read(struct ata_port
static void ahci_fill_sg(struct ata_queued_cmd *qc)
{
struct ahci_port_priv *pp = qc->ap->private_data;
- unsigned int i;
+ struct scatterlist *sg;
+ struct ahci_sg *ahci_sg;

VPRINTK("ENTER\n");

/*
* Next, the S/G list.
*/
- for (i = 0; i < qc->n_elem; i++) {
- u32 sg_len;
- dma_addr_t addr;
-
- addr = sg_dma_address(&qc->sg[i]);
- sg_len = sg_dma_len(&qc->sg[i]);
-
- pp->cmd_tbl_sg[i].addr = cpu_to_le32(addr & 0xffffffff);
- pp->cmd_tbl_sg[i].addr_hi = cpu_to_le32((addr >> 16) >> 16);
- pp->cmd_tbl_sg[i].flags_size = cpu_to_le32(sg_len - 1);
+ ahci_sg = pp->cmd_tbl_sg;
+ ata_for_each_sg(sg, qc) {
+ dma_addr_t addr = sg_dma_address(sg);
+ u32 sg_len = sg_dma_len(sg);
+
+ ahci_sg->addr = cpu_to_le32(addr & 0xffffffff);
+ ahci_sg->addr_hi = cpu_to_le32((addr >> 16) >> 16);
+ ahci_sg->flags_size = cpu_to_le32(sg_len - 1);
+ ahci_sg++;
}
}

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index ff18fa7..e1346cd 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2390,8 +2390,9 @@ static void ata_dev_init_params(struct a
static void ata_sg_clean(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg = qc->__sg;
int dir = qc->dma_dir;
+ void *pad_buf = NULL;

assert(qc->flags & ATA_QCFLAG_DMAMAP);
assert(sg != NULL);
@@ -2401,14 +2402,35 @@ static void ata_sg_clean(struct ata_queu

DPRINTK("unmapping %u sg elements\n", qc->n_elem);

- if (qc->flags & ATA_QCFLAG_SG)
+ /* 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->flags & ATA_QCFLAG_SG) {
dma_unmap_sg(ap->host_set->dev, sg, qc->n_elem, dir);
- else
+ /* restore last sg */
+ sg[qc->orig_n_elem - 1].length += qc->pad_len;
+ if (pad_buf) {
+ struct scatterlist *psg = &qc->pad_sgent;
+ void *addr = kmap_atomic(psg->page, KM_IRQ0);
+ memcpy(addr + psg->offset, pad_buf, qc->pad_len);
+ kunmap_atomic(psg->page, KM_IRQ0);
+ }
+ } else {
dma_unmap_single(ap->host_set->dev, sg_dma_address(&sg[0]),
sg_dma_len(&sg[0]), dir);
+ /* restore sg */
+ sg->length += qc->pad_len;
+ if (pad_buf)
+ memcpy(qc->buf_virt + sg->length - qc->pad_len,
+ pad_buf, qc->pad_len);
+ }

qc->flags &= ~ATA_QCFLAG_DMAMAP;
- qc->sg = NULL;
+ qc->__sg = NULL;
}

/**
@@ -2424,15 +2446,15 @@ static void ata_sg_clean(struct ata_queu
*/
static void ata_fill_sg(struct ata_queued_cmd *qc)
{
- struct scatterlist *sg = qc->sg;
struct ata_port *ap = qc->ap;
- unsigned int idx, nelem;
+ struct scatterlist *sg;
+ unsigned int idx;

- assert(sg != NULL);
+ assert(qc->__sg != NULL);
assert(qc->n_elem > 0);

idx = 0;
- for (nelem = qc->n_elem; nelem; nelem--,sg++) {
+ ata_for_each_sg(sg, qc) {
u32 addr, offset;
u32 sg_len, len;

@@ -2518,12 +2540,18 @@ void ata_qc_prep(struct ata_queued_cmd *

void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
+ struct scatterlist *sg;
+
qc->flags |= ATA_QCFLAG_SINGLE;

- qc->sg = &qc->sgent;
+ memset(&qc->sgent, 0, sizeof(qc->sgent));
+ qc->__sg = &qc->sgent;
qc->n_elem = 1;
+ qc->orig_n_elem = 1;
qc->buf_virt = buf;
- sg_init_one(qc->sg, buf, buflen);
+
+ sg = qc->__sg;
+ sg_init_one(sg, buf, buflen);
}

/**
@@ -2544,8 +2572,9 @@ void ata_sg_init(struct ata_queued_cmd *
unsigned int n_elem)
{
qc->flags |= ATA_QCFLAG_SG;
- qc->sg = sg;
+ qc->__sg = sg;
qc->n_elem = n_elem;
+ qc->orig_n_elem = n_elem;
}

/**
@@ -2565,9 +2594,32 @@ static int ata_sg_setup_one(struct ata_q
{
struct ata_port *ap = qc->ap;
int dir = qc->dma_dir;
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg = qc->__sg;
dma_addr_t dma_address;

+ /* we must lengthen transfers to end on a 32-bit boundary */
+ qc->pad_len = sg->length & 3;
+ if (qc->pad_len) {
+ void *pad_buf = ap->pad + (qc->tag * ATA_DMA_PAD_SZ);
+ struct scatterlist *psg = &qc->pad_sgent;
+
+ assert(qc->dev->class == ATA_DEV_ATAPI);
+
+ memset(pad_buf, 0, ATA_DMA_PAD_SZ);
+
+ if (qc->tf.flags & ATA_TFLAG_WRITE)
+ memcpy(pad_buf, qc->buf_virt + sg->length - qc->pad_len,
+ qc->pad_len);
+
+ sg_dma_address(psg) = ap->pad_dma + (qc->tag * ATA_DMA_PAD_SZ);
+ sg_dma_len(psg) = ATA_DMA_PAD_SZ;
+ /* trim sg */
+ sg->length -= qc->pad_len;
+
+ DPRINTK("padding done, sg->length=%u pad_len=%u\n",
+ sg->length, qc->pad_len);
+ }
+
dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,
sg->length, dir);
if (dma_mapping_error(dma_address))
@@ -2599,12 +2651,47 @@ static int ata_sg_setup_one(struct ata_q
static int ata_sg_setup(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg = qc->__sg;
+ struct scatterlist *lsg = &sg[qc->n_elem - 1];
int n_elem, dir;

VPRINTK("ENTER, ata%u\n", ap->id);
assert(qc->flags & ATA_QCFLAG_SG);

+ /* we must lengthen transfers to end on a 32-bit boundary */
+ qc->pad_len = lsg->length & 3;
+ if (qc->pad_len) {
+ void *pad_buf = ap->pad + (qc->tag * ATA_DMA_PAD_SZ);
+ struct scatterlist *psg = &qc->pad_sgent;
+ unsigned int offset;
+
+ assert(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;
+ psg->page = nth_page(lsg->page, offset >> PAGE_SHIFT);
+ psg->offset = offset_in_page(offset);
+
+ if (qc->tf.flags & ATA_TFLAG_WRITE) {
+ void *addr = kmap_atomic(psg->page, KM_IRQ0);
+ memcpy(pad_buf, addr + psg->offset, qc->pad_len);
+ kunmap_atomic(psg->page, KM_IRQ0);
+ }
+
+ sg_dma_address(psg) = ap->pad_dma + (qc->tag * ATA_DMA_PAD_SZ);
+ sg_dma_len(psg) = ATA_DMA_PAD_SZ;
+ /* trim last sg */
+ lsg->length -= qc->pad_len;
+
+ DPRINTK("padding done, sg[%d].length=%u pad_len=%u\n",
+ qc->n_elem - 1, lsg->length, qc->pad_len);
+ }
+
dir = qc->dma_dir;
n_elem = dma_map_sg(ap->host_set->dev, sg, qc->n_elem, dir);
if (n_elem < 1)
@@ -2880,7 +2967,7 @@ static void ata_data_xfer(struct ata_por
static void ata_pio_sector(struct ata_queued_cmd *qc)
{
int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg = qc->__sg;
struct ata_port *ap = qc->ap;
struct page *page;
unsigned int offset;
@@ -2930,7 +3017,7 @@ static void ata_pio_sector(struct ata_qu
static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
{
int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg = qc->__sg;
struct ata_port *ap = qc->ap;
struct page *page;
unsigned char *buf;
@@ -2963,7 +3050,7 @@ next_sg:
return;
}

- sg = &qc->sg[qc->cursg];
+ sg = &qc->__sg[qc->cursg];

page = sg->page;
offset = sg->offset + qc->cursg_ofs;
@@ -3320,7 +3407,7 @@ struct ata_queued_cmd *ata_qc_new_init(s

qc = ata_qc_new(ap);
if (qc) {
- qc->sg = NULL;
+ qc->__sg = NULL;
qc->flags = 0;
qc->scsicmd = NULL;
qc->ap = ap;
@@ -4004,11 +4091,18 @@ err_out:
int ata_port_start (struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
+ int rc;

ap->prd = dma_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) {
+ dma_free_coherent(dev, ATA_PRD_TBL_SZ, ap->prd, ap->prd_dma);
+ return rc;
+ }
+
DPRINTK("prd alloc, virt %p, dma %llx\n", ap->prd, (unsigned long long) ap->prd_dma);

return 0;
@@ -4032,6 +4126,7 @@ void ata_port_stop (struct ata_port *ap)
struct device *dev = ap->host_set->dev;

dma_free_coherent(dev, ATA_PRD_TBL_SZ, ap->prd, ap->prd_dma);
+ ata_pad_free(ap, dev);
}

void ata_host_stop (struct ata_host_set *host_set)
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 248baae..eb604b0 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -355,10 +355,10 @@ struct ata_queued_cmd *ata_scsi_qc_new(s
qc->scsidone = done;

if (cmd->use_sg) {
- qc->sg = (struct scatterlist *) cmd->request_buffer;
+ qc->__sg = (struct scatterlist *) cmd->request_buffer;
qc->n_elem = cmd->use_sg;
} else {
- qc->sg = &qc->sgent;
+ qc->__sg = &qc->sgent;
qc->n_elem = 1;
}
} else {
@@ -702,6 +702,16 @@ int ata_scsi_slave_config(struct scsi_de
*/
blk_queue_max_sectors(sdev->request_queue, 2048);
}
+
+ /*
+ * 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) {
+ request_queue_t *q = sdev->request_queue;
+ blk_queue_max_hw_segments(q, q->max_hw_segments - 1);
+ }
}

return 0; /* scsi layer doesn't check return value, sigh */
diff --git a/drivers/scsi/pdc_adma.c b/drivers/scsi/pdc_adma.c
index 665017e..a50588c 100644
--- a/drivers/scsi/pdc_adma.c
+++ b/drivers/scsi/pdc_adma.c
@@ -293,14 +293,14 @@ static void adma_eng_timeout(struct ata_

static int adma_fill_sg(struct ata_queued_cmd *qc)
{
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg;
struct ata_port *ap = qc->ap;
struct adma_port_priv *pp = ap->private_data;
u8 *buf = pp->pkt;
- int nelem, i = (2 + buf[3]) * 8;
+ int i = (2 + buf[3]) * 8;
u8 pFLAGS = pORD | ((qc->tf.flags & ATA_TFLAG_WRITE) ? pDIRO : 0);

- for (nelem = 0; nelem < qc->n_elem; nelem++,sg++) {
+ ata_for_each_sg(sg, qc) {
u32 addr;
u32 len;

@@ -312,7 +312,7 @@ static int adma_fill_sg(struct ata_queue
*(__le32 *)(buf + i) = cpu_to_le32(len);
i += 4;

- if ((nelem + 1) == qc->n_elem)
+ if (ata_sg_is_last(sg, qc))
pFLAGS |= pEND;
buf[i++] = pFLAGS;
buf[i++] = qc->dev->dma_mode & 0xf;
diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index 46dbdee..0f469e3 100644
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -670,6 +670,11 @@ static void mv_host_stop(struct ata_host
ata_host_stop(host_set);
}

+static inline void mv_priv_free(struct mv_port_priv *pp, struct device *dev)
+{
+ dma_free_coherent(dev, MV_PORT_PRIV_DMA_SZ, pp->crpb, pp->crpb_dma);
+}
+
/**
* mv_port_start - Port specific init/start routine.
* @ap: ATA channel to manipulate
@@ -687,21 +692,23 @@ static int mv_port_start(struct ata_port
void __iomem *port_mmio = mv_ap_base(ap);
void *mem;
dma_addr_t mem_dma;
+ int rc = -ENOMEM;

pp = kmalloc(sizeof(*pp), GFP_KERNEL);
- if (!pp) {
- return -ENOMEM;
- }
+ if (!pp)
+ goto err_out;
memset(pp, 0, sizeof(*pp));

mem = dma_alloc_coherent(dev, MV_PORT_PRIV_DMA_SZ, &mem_dma,
GFP_KERNEL);
- if (!mem) {
- kfree(pp);
- return -ENOMEM;
- }
+ if (!mem)
+ goto err_out_pp;
memset(mem, 0, MV_PORT_PRIV_DMA_SZ);

+ rc = ata_pad_alloc(ap, dev);
+ if (rc)
+ goto err_out_priv;
+
/* First item in chunk of DMA memory:
* 32-slot command request table (CRQB), 32 bytes each in size
*/
@@ -746,6 +753,13 @@ static int mv_port_start(struct ata_port
*/
ap->private_data = pp;
return 0;
+
+err_out_priv:
+ mv_priv_free(pp, dev);
+err_out_pp:
+ kfree(pp);
+err_out:
+ return rc;
}

/**
@@ -768,7 +782,8 @@ static void mv_port_stop(struct ata_port
spin_unlock_irqrestore(&ap->host_set->lock, flags);

ap->private_data = NULL;
- dma_free_coherent(dev, MV_PORT_PRIV_DMA_SZ, pp->crpb, pp->crpb_dma);
+ ata_pad_free(ap, dev);
+ mv_priv_free(pp, dev);
kfree(pp);
}

@@ -784,23 +799,24 @@ static void mv_port_stop(struct ata_port
static void mv_fill_sg(struct ata_queued_cmd *qc)
{
struct mv_port_priv *pp = qc->ap->private_data;
- unsigned int i;
+ unsigned int i = 0;
+ struct scatterlist *sg;

- for (i = 0; i < qc->n_elem; i++) {
+ ata_for_each_sg(sg, qc) {
u32 sg_len;
dma_addr_t addr;

- addr = sg_dma_address(&qc->sg[i]);
- sg_len = sg_dma_len(&qc->sg[i]);
+ addr = sg_dma_address(sg);
+ sg_len = sg_dma_len(sg);

pp->sg_tbl[i].addr = cpu_to_le32(addr & 0xffffffff);
pp->sg_tbl[i].addr_hi = cpu_to_le32((addr >> 16) >> 16);
assert(0 == (sg_len & ~MV_DMA_BOUNDARY));
pp->sg_tbl[i].flags_size = cpu_to_le32(sg_len);
- }
- if (0 < qc->n_elem) {
- pp->sg_tbl[qc->n_elem - 1].flags_size |=
- cpu_to_le32(EPRD_FLAG_END_OF_TBL);
+ if (ata_sg_is_last(sg, qc))
+ pp->sg_tbl[i].flags_size |= cpu_to_le32(EPRD_FLAG_END_OF_TBL);
+
+ i++;
}
}

diff --git a/drivers/scsi/sata_qstor.c b/drivers/scsi/sata_qstor.c
index 9938dae..65502c1 100644
--- a/drivers/scsi/sata_qstor.c
+++ b/drivers/scsi/sata_qstor.c
@@ -271,16 +271,17 @@ static void qs_scr_write (struct ata_por

static void qs_fill_sg(struct ata_queued_cmd *qc)
{
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg;
struct ata_port *ap = qc->ap;
struct qs_port_priv *pp = ap->private_data;
unsigned int nelem;
u8 *prd = pp->pkt + QS_CPB_BYTES;

- assert(sg != NULL);
+ assert(qc->__sg != NULL);
assert(qc->n_elem > 0);

- for (nelem = 0; nelem < qc->n_elem; nelem++,sg++) {
+ nelem = 0;
+ ata_for_each_sg(sg, qc) {
u64 addr;
u32 len;

@@ -294,6 +295,7 @@ static void qs_fill_sg(struct ata_queued

VPRINTK("PRD[%u] = (0x%llX, 0x%X)\n", nelem,
(unsigned long long)addr, len);
+ nelem++;
}
}

diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index c665480..e6c8e89 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -411,15 +411,20 @@ static void sil24_phy_reset(struct ata_p
static inline void sil24_fill_sg(struct ata_queued_cmd *qc,
struct sil24_cmd_block *cb)
{
- struct scatterlist *sg = qc->sg;
struct sil24_sge *sge = cb->sge;
- unsigned i;
+ struct scatterlist *sg;
+ unsigned int idx = 0;

- for (i = 0; i < qc->n_elem; i++, sg++, sge++) {
+ ata_for_each_sg(sg, qc) {
sge->addr = cpu_to_le64(sg_dma_address(sg));
sge->cnt = cpu_to_le32(sg_dma_len(sg));
- sge->flags = 0;
- sge->flags = i < qc->n_elem - 1 ? 0 : cpu_to_le32(SGE_TRM);
+ if (ata_sg_is_last(sg, qc))
+ sge->flags = cpu_to_le32(SGE_TRM);
+ else
+ sge->flags = 0;
+
+ sge++;
+ idx++;
}
}

@@ -630,6 +635,13 @@ static irqreturn_t sil24_interrupt(int i
return IRQ_RETVAL(handled);
}

+static inline void sil24_cblk_free(struct sil24_port_priv *pp, struct device *dev)
+{
+ const size_t cb_size = sizeof(*pp->cmd_block);
+
+ dma_free_coherent(dev, cb_size, pp->cmd_block, pp->cmd_block_dma);
+}
+
static int sil24_port_start(struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
@@ -637,36 +649,44 @@ static int sil24_port_start(struct ata_p
struct sil24_cmd_block *cb;
size_t cb_size = sizeof(*cb);
dma_addr_t cb_dma;
+ int rc = -ENOMEM;

- pp = kmalloc(sizeof(*pp), GFP_KERNEL);
+ pp = kzalloc(sizeof(*pp), GFP_KERNEL);
if (!pp)
- return -ENOMEM;
- memset(pp, 0, sizeof(*pp));
+ goto err_out;

pp->tf.command = ATA_DRDY;

cb = dma_alloc_coherent(dev, cb_size, &cb_dma, GFP_KERNEL);
- if (!cb) {
- kfree(pp);
- return -ENOMEM;
- }
+ if (!cb)
+ goto err_out_pp;
memset(cb, 0, cb_size);

+ rc = ata_pad_alloc(ap, dev);
+ if (rc)
+ goto err_out_pad;
+
pp->cmd_block = cb;
pp->cmd_block_dma = cb_dma;

ap->private_data = pp;

return 0;
+
+err_out_pad:
+ sil24_cblk_free(pp, dev);
+err_out_pp:
+ kfree(pp);
+err_out:
+ return rc;
}

static void sil24_port_stop(struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
struct sil24_port_priv *pp = ap->private_data;
- size_t cb_size = sizeof(*pp->cmd_block);

- dma_free_coherent(dev, cb_size, pp->cmd_block, pp->cmd_block_dma);
+ sil24_cblk_free(pp, dev);
kfree(pp);
}

diff --git a/drivers/scsi/sata_sx4.c b/drivers/scsi/sata_sx4.c
index 0ec21e0..f859bbd 100644
--- a/drivers/scsi/sata_sx4.c
+++ b/drivers/scsi/sata_sx4.c
@@ -450,14 +450,14 @@ static inline void pdc20621_host_pkt(str

static void pdc20621_dma_prep(struct ata_queued_cmd *qc)
{
- struct scatterlist *sg = qc->sg;
+ struct scatterlist *sg;
struct ata_port *ap = qc->ap;
struct pdc_port_priv *pp = ap->private_data;
void __iomem *mmio = ap->host_set->mmio_base;
struct pdc_host_priv *hpriv = ap->host_set->private_data;
void __iomem *dimm_mmio = hpriv->dimm_mmio;
unsigned int portno = ap->port_no;
- unsigned int i, last, idx, total_len = 0, sgt_len;
+ unsigned int i, idx, total_len = 0, sgt_len;
u32 *buf = (u32 *) &pp->dimm_buf[PDC_DIMM_HEADER_SZ];

assert(qc->flags & ATA_QCFLAG_DMAMAP);
@@ -470,12 +470,11 @@ static void pdc20621_dma_prep(struct ata
/*
* Build S/G table
*/
- last = qc->n_elem;
idx = 0;
- for (i = 0; i < last; i++) {
- buf[idx++] = cpu_to_le32(sg_dma_address(&sg[i]));
- buf[idx++] = cpu_to_le32(sg_dma_len(&sg[i]));
- total_len += sg_dma_len(&sg[i]);
+ ata_for_each_sg(sg, qc) {
+ buf[idx++] = cpu_to_le32(sg_dma_address(sg));
+ buf[idx++] = cpu_to_le32(sg_dma_len(sg));
+ total_len += sg_dma_len(sg);
}
buf[idx - 1] |= cpu_to_le32(ATA_PRD_EOT);
sgt_len = idx * 4;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 0ba3af7..dcd17e7 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -155,6 +155,10 @@ enum {
ATA_SHIFT_UDMA = 0,
ATA_SHIFT_MWDMA = 8,
ATA_SHIFT_PIO = 11,
+
+ /* 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,

/* Masks for port functions */
ATA_PORT_PRIMARY = (1 << 0),
@@ -249,9 +253,12 @@ struct ata_queued_cmd {
unsigned long flags; /* ATA_QCFLAG_xxx */
unsigned int tag;
unsigned int n_elem;
+ unsigned int orig_n_elem;

int dma_dir;

+ unsigned int pad_len;
+
unsigned int nsect;
unsigned int cursect;

@@ -262,9 +269,11 @@ struct ata_queued_cmd {
unsigned int cursg_ofs;

struct scatterlist sgent;
+ struct scatterlist pad_sgent;
void *buf_virt;

- struct scatterlist *sg;
+ /* DO NOT iterate over __sg manually, use ata_for_each_sg() */
+ struct scatterlist *__sg;

ata_qc_cb_t complete_fn;

@@ -310,6 +319,9 @@ 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 */
@@ -512,6 +524,31 @@ extern int pci_test_config_bits(struct p
#endif /* CONFIG_PCI */


+static inline int
+ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
+{
+ if (sg == &qc->pad_sgent)
+ return 1;
+ if (qc->pad_len)
+ return 0;
+ if (((sg - qc->__sg) + 1) == qc->n_elem)
+ return 1;
+ return 0;
+}
+
+static inline struct scatterlist *
+ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
+{
+ if (sg == &qc->pad_sgent)
+ return NULL;
+ if (++sg - qc->__sg < qc->n_elem)
+ return sg;
+ return qc->pad_len ? &qc->pad_sgent : NULL;
+}
+
+#define ata_for_each_sg(sg, qc) \
+ for (sg = qc->__sg; sg; sg = ata_qc_next_sg(sg, qc))
+
static inline unsigned int ata_tag_valid(unsigned int tag)
{
return (tag < ATA_MAX_QUEUE) ? 1 : 0;
@@ -740,4 +777,17 @@ static inline unsigned int __ac_err_mask
return mask;
}

+static inline int ata_pad_alloc(struct ata_port *ap, struct device *dev)
+{
+ ap->pad_dma = 0;
+ ap->pad = dma_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)
+{
+ dma_free_coherent(dev, ATA_DMA_PAD_BUF_SZ, ap->pad, ap->pad_dma);
+}
+
#endif /* __LINUX_LIBATA_H__ */
-
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