libata: kill qc->nsect and cursect

libata used two separate sets of variables to record request size and
current offset for ATA and ATAPI.  This is confusing and fragile.
This patch replaces qc->nsect/cursect with qc->nbytes/curbytes and
kills them.  Also, ata_pio_sector() is updated to use bytes for
qc->cursg_ofs instead of sectors.  The field used to be used in bytes
for ATAPI and in sectors for ATA.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

6 files changed, 13 insertions, 25 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 89f3cf57b677..c1444d8f92c6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1249,7 +1249,6 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
                         buflen += sg[i].length;
 
                 ata_sg_init(qc, sg, n_elem);
-                qc->nsect = buflen / ATA_SECT_SIZE;
                 qc->nbytes = buflen;
         }
 
@@ -4006,11 +4005,11 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
         unsigned int offset;
         unsigned char *buf;
 
-        if (qc->cursect == (qc->nsect - 1))
+        if (qc->curbytes == qc->nbytes - ATA_SECT_SIZE)
                 ap->hsm_task_state = HSM_ST_LAST;
 
         page = sg[qc->cursg].page;
-        offset = sg[qc->cursg].offset + qc->cursg_ofs * ATA_SECT_SIZE;
+        offset = sg[qc->cursg].offset + qc->cursg_ofs;
 
         /* get the current page and offset */
         page = nth_page(page, (offset >> PAGE_SHIFT));
@@ -4035,10 +4034,10 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
                 ap->ops->data_xfer(qc->dev, buf + offset, ATA_SECT_SIZE, do_write);
         }
 
-        qc->cursect++;
-        qc->cursg_ofs++;
+        qc->curbytes += ATA_SECT_SIZE;
+        qc->cursg_ofs += ATA_SECT_SIZE;
 
-        if ((qc->cursg_ofs * ATA_SECT_SIZE) == (&sg[qc->cursg])->length) {
+        if (qc->cursg_ofs == (&sg[qc->cursg])->length) {
                 qc->cursg++;
                 qc->cursg_ofs = 0;
         }
@@ -4063,7 +4062,8 @@ static void ata_pio_sectors(struct ata_queued_cmd *qc)
 
                 WARN_ON(qc->dev->multi_count == 0);
 
-                nsect = min(qc->nsect - qc->cursect, qc->dev->multi_count);
+                nsect = min((qc->nbytes - qc->curbytes) / ATA_SECT_SIZE,
+                            qc->dev->multi_count);
                 while (nsect--)
                         ata_pio_sector(qc);
         } else
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 748435807d68..52c85af7fe99 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1443,15 +1443,10 @@ static void ata_eh_report(struct ata_port *ap)
                 };
                 struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
                 struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
-                unsigned int nbytes;
 
                 if (!(qc->flags & ATA_QCFLAG_FAILED) || !qc->err_mask)
                         continue;
 
-                nbytes = qc->nbytes;
-                if (!nbytes)
-                        nbytes = qc->nsect << 9;
-
                 ata_dev_printk(qc->dev, KERN_ERR,
                         "cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
                         "tag %d cdb 0x%x data %u %s\n         "
@@ -1461,7 +1456,7 @@ static void ata_eh_report(struct ata_port *ap)
                         cmd->lbal, cmd->lbam, cmd->lbah,
                         cmd->hob_feature, cmd->hob_nsect,
                         cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
-                        cmd->device, qc->tag, qc->cdb[0], nbytes,
+                        cmd->device, qc->tag, qc->cdb[0], qc->nbytes,
                         dma_str[qc->dma_dir],
                         res->command, res->feature, res->nsect,
                         res->lbal, res->lbam, res->lbah,
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 6a99c0824751..9b5088ab2742 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1359,7 +1359,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
                 goto nothing_to_do;
 
         qc->flags |= ATA_QCFLAG_IO;
-        qc->nsect = n_block;
+        qc->nbytes = n_block * ATA_SECT_SIZE;
 
         rc = ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags,
                              qc->tag);
@@ -2660,7 +2660,7 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
          * TODO: find out if we need to do more here to
          *       cover scatter/gather case.
          */
-        qc->nsect = scmd->request_bufflen / ATA_SECT_SIZE;
+        qc->nbytes = scmd->request_bufflen;
 
         /* request result TF */
         qc->flags |= ATA_QCFLAG_RESULT_TF;
diff --git a/drivers/ata/pata_pdc202xx_old.c b/drivers/ata/pata_pdc202xx_old.c
index ad691b9e7743..ba982ba68ad5 100644
--- a/drivers/ata/pata_pdc202xx_old.c
+++ b/drivers/ata/pata_pdc202xx_old.c
@@ -189,10 +189,7 @@ static void pdc2026x_bmdma_start(struct ata_queued_cmd *qc)
         /* Cases the state machine will not complete correctly without help */
         if ((tf->flags & ATA_TFLAG_LBA48) ||  tf->protocol == ATA_PROT_ATAPI_DMA)
         {
-                if (tf->flags & ATA_TFLAG_LBA48)
-                        len = qc->nsect * 512;
-                else
-                        len = qc->nbytes;
+                len = qc->nbytes;
 
                 if (tf->flags & ATA_TFLAG_WRITE)
                         len |= 0x06000000;
diff --git a/drivers/ata/sata_qstor.c b/drivers/ata/sata_qstor.c
index 710909df4eaf..0292a79f9747 100644
--- a/drivers/ata/sata_qstor.c
+++ b/drivers/ata/sata_qstor.c
@@ -325,7 +325,7 @@ static void qs_qc_prep(struct ata_queued_cmd *qc)
         /* host control block (HCB) */
         buf[ 0] = QS_HCB_HDR;
         buf[ 1] = hflags;
-        *(__le32 *)(&buf[ 4]) = cpu_to_le32(qc->nsect * ATA_SECT_SIZE);
+        *(__le32 *)(&buf[ 4]) = cpu_to_le32(qc->nbytes);
         *(__le32 *)(&buf[ 8]) = cpu_to_le32(nelem);
         addr = ((u64)pp->pkt_dma) + QS_CPB_BYTES;
         *(__le64 *)(&buf[16]) = cpu_to_le64(addr);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a8ecaaad55ff..a2458dfefb17 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -427,9 +427,6 @@ struct ata_queued_cmd {
 
         unsigned int            pad_len;
 
-        unsigned int            nsect;
-        unsigned int            cursect;
-
         unsigned int            nbytes;
         unsigned int            curbytes;
 
@@ -1145,8 +1142,7 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
         qc->dma_dir = DMA_NONE;
         qc->__sg = NULL;
         qc->flags = 0;
-        qc->cursect = qc->cursg = qc->cursg_ofs = 0;
-        qc->nsect = 0;
+        qc->cursg = qc->cursg_ofs = 0;
         qc->nbytes = qc->curbytes = 0;
         qc->n_elem = 0;
         qc->err_mask = 0;