[SCSI] ide-scsi: remove usage of sg_last()

We want to remove sg_last(), it's a very expensive interface. So
keep track of number of sg entries in the sg list, instead of comparing
with the last entry.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index bd74f6c44b6b80bf3675b7f4cd1d2ad4e4193bce..fa7ba64483fb4c3976518f909365f1156bef9262 100644 (file)
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -70,7 +70,7 @@ typedef struct idescsi_pc_s {
        u8 *buffer;                             /* Data buffer */
        u8 *current_position;                   /* Pointer into the above buffer */
        struct scatterlist *sg;                 /* Scatter gather table */
-       struct scatterlist *last_sg;            /* Last sg element */
+       unsigned int sg_cnt;                    /* Number of entries in sg */
        int b_count;                            /* Bytes transferred from current entry */
        struct scsi_cmnd *scsi_cmd;             /* SCSI command */
        void (*done)(struct scsi_cmnd *);       /* Scsi completion routine */
@@ -192,7 +192,7 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
                }
                bcount -= count; pc->b_count += count;
                if (pc->b_count == pc->sg->length) {
-                       if (pc->sg == pc->last_sg)
+                       if (!--pc->sg_cnt)
                                break;
                        pc->sg = sg_next(pc->sg);
                        pc->b_count = 0;
@@ -229,7 +229,7 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
                }
                bcount -= count; pc->b_count += count;
                if (pc->b_count == pc->sg->length) {
-                       if (pc->sg == pc->last_sg)
+                       if (!--pc->sg_cnt)
                                break;
                        pc->sg = sg_next(pc->sg);
                        pc->b_count = 0;
@@ -807,7 +807,7 @@ static int idescsi_queue (struct scsi_cmnd *cmd,
        memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
        pc->buffer = NULL;
        pc->sg = scsi_sglist(cmd);
-       pc->last_sg = sg_last(pc->sg, scsi_sg_count(cmd));
+       pc->sg_cnt = scsi_sg_count(cmd);
        pc->b_count = 0;
        pc->request_transfer = pc->buffer_size = scsi_bufflen(cmd);
        pc->scsi_cmd = cmd;