libata-scsi: Remove !use_sg code paths

     This is a minimal patch needed to remove use of !use_sg
     but it is not a complete clean up of the !use_sg paths.
     Libata-core still has the qc->flags & ATA_QCFLAG_SG
     and !qc->n_elem code paths. Perhaps an ata maintainer
     would have a go at it.

     - TODO: further cleanup of qc->flags & ATA_QCFLAG_SG
       and !qc->n_elem code paths in libata-core
     - TODO: Use scsi_dma_{map,unmap} where applicable.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 9 insertions, 22 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index f0f586b56c20..598ef1018e19 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -450,13 +450,8 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
                 qc->scsicmd = cmd;
                 qc->scsidone = done;
 
-                if (cmd->use_sg) {
-                        qc->__sg = (struct scatterlist *) cmd->request_buffer;
-                        qc->n_elem = cmd->use_sg;
-                } else if (cmd->request_bufflen) {
-                        qc->__sg = &qc->sgent;
-                        qc->n_elem = 1;
-                }
+                qc->__sg = (struct scatterlist *) cmd->request_buffer;
+                qc->n_elem = cmd->use_sg;
         } else {
                 cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
                 done(cmd);
@@ -1504,11 +1499,7 @@ static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
                         goto err_did;
                 }
 
-                if (cmd->use_sg)
-                        ata_sg_init(qc, cmd->request_buffer, cmd->use_sg);
-                else
-                        ata_sg_init_one(qc, cmd->request_buffer,
-                                        cmd->request_bufflen);
+                ata_sg_init(qc, cmd->request_buffer, cmd->use_sg);
 
                 qc->dma_dir = cmd->sc_data_direction;
         }
@@ -1562,15 +1553,14 @@ static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out)
         u8 *buf;
         unsigned int buflen;
 
-        if (cmd->use_sg) {
-                struct scatterlist *sg;
+        struct scatterlist *sg = (struct scatterlist *) cmd->request_buffer;
 
-                sg = (struct scatterlist *) cmd->request_buffer;
+        if (sg) {
                 buf = kmap_atomic(sg->page, KM_IRQ0) + sg->offset;
                 buflen = sg->length;
         } else {
-                buf = cmd->request_buffer;
-                buflen = cmd->request_bufflen;
+                buf = NULL;
+                buflen = 0;
         }
 
         *buf_out = buf;
@@ -1590,12 +1580,9 @@ static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out)
 
 static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, u8 *buf)
 {
-        if (cmd->use_sg) {
-                struct scatterlist *sg;
-
-                sg = (struct scatterlist *) cmd->request_buffer;
+        struct scatterlist *sg = (struct scatterlist *) cmd->request_buffer;
+        if (sg)
                 kunmap_atomic(buf - sg->offset, KM_IRQ0);
-        }
 }
 
 /**