libata: kill non-sg DMA interface

With atapi_request_sense() converted to use sg, there's no user of
non-sg interface.  Kill non-sg interface.

* ATA_QCFLAG_SINGLE and ATA_QCFLAG_SG are removed.  ATA_QCFLAG_DMAMAP
  is used instead.  (this way no LLD change is necessary)

* qc->buf_virt is removed.

* ata_sg_init_one() and ata_sg_setup_one() are removed.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 16 insertions, 139 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 39cedd949ed4..76360f0ca20d 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4478,9 +4478,6 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
         WARN_ON(!(qc->flags & ATA_QCFLAG_DMAMAP));
         WARN_ON(sg == NULL);
 
-        if (qc->flags & ATA_QCFLAG_SINGLE)
-                WARN_ON(qc->n_elem > 1);
-
         VPRINTK("unmapping %u sg elements\n", qc->n_elem);
 
         /* if we padded the buffer out to 32-bit bound, and data
@@ -4490,27 +4487,15 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
         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) {
-                if (qc->n_elem)
-                        dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);
-                /* restore last sg */
-                sg_last(sg, qc->orig_n_elem)->length += qc->pad_len;
-                if (pad_buf) {
-                        struct scatterlist *psg = &qc->pad_sgent;
-                        void *addr = kmap_atomic(sg_page(psg), KM_IRQ0);
-                        memcpy(addr + psg->offset, pad_buf, qc->pad_len);
-                        kunmap_atomic(addr, KM_IRQ0);
-                }
-        } else {
-                if (qc->n_elem)
-                        dma_unmap_single(ap->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);
+        if (qc->n_elem)
+                dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);
+        /* restore last sg */
+        sg_last(sg, qc->orig_n_elem)->length += qc->pad_len;
+        if (pad_buf) {
+                struct scatterlist *psg = &qc->pad_sgent;
+                void *addr = kmap_atomic(sg_page(psg), KM_IRQ0);
+                memcpy(addr + psg->offset, pad_buf, qc->pad_len);
+                kunmap_atomic(addr, KM_IRQ0);
         }
 
         qc->flags &= ~ATA_QCFLAG_DMAMAP;
@@ -4765,33 +4750,6 @@ void ata_dumb_qc_prep(struct ata_queued_cmd *qc)
 void ata_noop_qc_prep(struct ata_queued_cmd *qc) { }
 
 /**
- *      ata_sg_init_one - Associate command with memory buffer
- *      @qc: Command to be associated
- *      @buf: Memory buffer
- *      @buflen: Length of memory buffer, in bytes.
- *
- *      Initialize the data-related elements of queued_cmd @qc
- *      to point to a single memory buffer, @buf of byte length @buflen.
- *
- *      LOCKING:
- *      spin_lock_irqsave(host lock)
- */
-
-void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
-{
-        qc->flags |= ATA_QCFLAG_SINGLE;
-
-        qc->__sg = &qc->sgent;
-        qc->n_elem = 1;
-        qc->orig_n_elem = 1;
-        qc->buf_virt = buf;
-        qc->nbytes = buflen;
-        qc->cursg = qc->__sg;
-
-        sg_init_one(&qc->sgent, buf, buflen);
-}
-
-/**
  *      ata_sg_init - Associate command with scatter-gather table.
  *      @qc: Command to be associated
  *      @sg: Scatter-gather table.
@@ -4808,7 +4766,7 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
 void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
                  unsigned int n_elem)
 {
-        qc->flags |= ATA_QCFLAG_SG;
+        qc->flags |= ATA_QCFLAG_DMAMAP;
         qc->__sg = sg;
         qc->n_elem = n_elem;
         qc->orig_n_elem = n_elem;
@@ -4816,75 +4774,6 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
 }
 
 /**
- *      ata_sg_setup_one - DMA-map the memory buffer associated with a command.
- *      @qc: Command with memory buffer to be mapped.
- *
- *      DMA-map the memory buffer associated with queued_cmd @qc.
- *
- *      LOCKING:
- *      spin_lock_irqsave(host lock)
- *
- *      RETURNS:
- *      Zero on success, negative on error.
- */
-
-static int ata_sg_setup_one(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
-        int dir = qc->dma_dir;
-        struct scatterlist *sg = qc->__sg;
-        dma_addr_t dma_address;
-        int trim_sg = 0;
-
-        /* 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;
-
-                WARN_ON(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;
-                if (sg->length == 0)
-                        trim_sg = 1;
-
-                DPRINTK("padding done, sg->length=%u pad_len=%u\n",
-                        sg->length, qc->pad_len);
-        }
-
-        if (trim_sg) {
-                qc->n_elem--;
-                goto skip_map;
-        }
-
-        dma_address = dma_map_single(ap->dev, qc->buf_virt,
-                                     sg->length, dir);
-        if (dma_mapping_error(dma_address)) {
-                /* restore sg */
-                sg->length += qc->pad_len;
-                return -1;
-        }
-
-        sg_dma_address(sg) = dma_address;
-        sg_dma_len(sg) = sg->length;
-
-skip_map:
-        DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),
-                qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
-
-        return 0;
-}
-
-/**
  *      ata_sg_setup - DMA-map the scatter-gather table associated with a command.
  *      @qc: Command with scatter-gather table to be mapped.
  *
@@ -4906,7 +4795,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
         int n_elem, pre_n_elem, dir, trim_sg = 0;
 
         VPRINTK("ENTER, ata%u\n", ap->print_id);
-        WARN_ON(!(qc->flags & ATA_QCFLAG_SG));
+        WARN_ON(!(qc->flags & ATA_QCFLAG_DMAMAP));
 
         /* we must lengthen transfers to end on a 32-bit boundary */
         qc->pad_len = lsg->length & 3;
@@ -6025,16 +5914,10 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
 
         if (ata_is_dma(prot) || (ata_is_pio(prot) &&
                                  (ap->flags & ATA_FLAG_PIO_DMA))) {
-                if (qc->flags & ATA_QCFLAG_SG) {
-                        if (ata_sg_setup(qc))
-                                goto sg_err;
-                } else if (qc->flags & ATA_QCFLAG_SINGLE) {
-                        if (ata_sg_setup_one(qc))
-                                goto sg_err;
-                }
-        } else {
-                qc->flags &= ~ATA_QCFLAG_DMAMAP;
-        }
+                if (ata_sg_setup(qc))
+                        goto sg_err;
+        } else
+                qc->flags &= ATA_QCFLAG_DMAMAP;
 
         /* if device is sleeping, schedule softreset and abort the link */
         if (unlikely(qc->dev->flags & ATA_DFLAG_SLEEPING)) {
@@ -7612,7 +7495,6 @@ EXPORT_SYMBOL_GPL(ata_host_register);
 EXPORT_SYMBOL_GPL(ata_host_activate);
 EXPORT_SYMBOL_GPL(ata_host_detach);
 EXPORT_SYMBOL_GPL(ata_sg_init);
-EXPORT_SYMBOL_GPL(ata_sg_init_one);
 EXPORT_SYMBOL_GPL(ata_hsm_move);
 EXPORT_SYMBOL_GPL(ata_qc_complete);
 EXPORT_SYMBOL_GPL(ata_qc_complete_multiple);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 7fa96cb4f6db..acd90ad78417 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -219,9 +219,7 @@ enum {
 
         /* struct ata_queued_cmd flags */
         ATA_QCFLAG_ACTIVE       = (1 << 0), /* cmd not yet ack'd to scsi lyer */
-        ATA_QCFLAG_SG           = (1 << 1), /* have s/g table? */
-        ATA_QCFLAG_SINGLE       = (1 << 2), /* no s/g, just a single buffer */
-        ATA_QCFLAG_DMAMAP       = ATA_QCFLAG_SG | ATA_QCFLAG_SINGLE,
+        ATA_QCFLAG_DMAMAP       = (1 << 1), /* SG table is DMA mapped */
         ATA_QCFLAG_IO           = (1 << 3), /* standard IO command */
         ATA_QCFLAG_RESULT_TF    = (1 << 4), /* result TF requested */
         ATA_QCFLAG_CLEAR_EXCL   = (1 << 5), /* clear excl_link on completion */
@@ -475,7 +473,6 @@ struct ata_queued_cmd {
 
         struct scatterlist      sgent;
         struct scatterlist      pad_sgent;
-        void                    *buf_virt;
 
         /* DO NOT iterate over __sg manually, use ata_for_each_sg() */
         struct scatterlist      *__sg;
@@ -891,8 +888,6 @@ extern void ata_dumb_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_noop_qc_prep(struct ata_queued_cmd *qc);
 extern unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc);
-extern void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf,
-                unsigned int buflen);
 extern void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
                  unsigned int n_elem);
 extern unsigned int ata_dev_classify(const struct ata_taskfile *tf);