Commit c6132da1 authored by Jens Axboe's avatar Jens Axboe
Browse files

scsi: convert to using sg helpers 



This converts the SCSI mid layer to using the sg helpers for looking up
sg elements, instead of doing it manually.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent f565913e

drivers/scsi/scsi_lib.c

+13 −9
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/pci.h>

#include <linux/delay.h>

#include <linux/hardirq.h>

#include <linux/scatterlist.h>



#include <scsi/scsi.h>

#include <scsi/scsi_cmnd.h>
@@ -289,14 +290,16 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, 
	struct request_queue *q = rq->q;

	int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;

	unsigned int data_len = bufflen, len, bytes, off;

	struct scatterlist *sg;

	struct page *page;

	struct bio *bio = NULL;

	int i, err, nr_vecs = 0;



	for (i = 0; i < nsegs; i++) {

		page = sgl[i].page;

		off = sgl[i].offset;

		len = sgl[i].length;

	for_each_sg(sgl, sg, nsegs, i) {

		page = sg->page;

		off = sg->offset;

		len = sg->length;

 		data_len += len;



		while (len > 0 && data_len > 0) {

			/*
@@ -2193,18 +2196,19 @@ EXPORT_SYMBOL_GPL(scsi_target_unblock); 
 *

 * Returns virtual address of the start of the mapped page

 */

void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,

void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,

			  size_t *offset, size_t *len)

{

	int i;

	size_t sg_len = 0, len_complete = 0;

	struct scatterlist *sg;

	struct page *page;



	WARN_ON(!irqs_disabled());



	for (i = 0; i < sg_count; i++) {

	for_each_sg(sgl, sg, sg_count, i) {

		len_complete = sg_len; /* Complete sg-entries */

		sg_len += sg[i].length;

		sg_len += sg->length;

		if (sg_len > *offset)

			break;

	}
@@ -2218,10 +2222,10 @@ void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count, 
	}



	/* Offset starting from the beginning of first page in this sg-entry */

	*offset = *offset - len_complete + sg[i].offset;

	*offset = *offset - len_complete + sg->offset;



	/* Assumption: contiguous pages can be accessed as "page + i" */

	page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));

	page = nth_page(sg->page, (*offset >> PAGE_SHIFT));

	*offset &= ~PAGE_MASK;



	/* Bytes in this sg-entry from *offset to the end of the page */

include/scsi/scsi_cmnd.h

+2 −1
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/list.h>

#include <linux/types.h>

#include <linux/timer.h>

#include <linux/scatterlist.h>



struct request;

struct scatterlist;
@@ -148,6 +149,6 @@ static inline int scsi_get_resid(struct scsi_cmnd *cmd) 
}



#define scsi_for_each_sg(cmd, sg, nseg, __i)			\

	for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)

	for_each_sg(scsi_sglist(cmd), sg, nseg, __i)



#endif /* _SCSI_SCSI_CMND_H */