Commit c79d88b7 authored by Jens Axboe's avatar Jens Axboe
Browse files

[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: default avatarJens Axboe <jens.axboe@oracle.com>
parent 5804509e

drivers/scsi/ide-scsi.c

+4 −4
Original line number Diff line number Diff line
@@ -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;