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authorJens Axboe <jens.axboe@oracle.com>2007-10-16 12:29:34 +0200
committerJens Axboe <jens.axboe@oracle.com>2007-10-16 12:29:34 +0200
commit3eed13fd933dbb81db12f7cdec6de9268c4443b5 (patch)
treec16913706acffd4a0b29ec12cd68906b708c9a8a /block
parentMerge branch 'barrier' into for-linus (diff)
parentSPARC64: sg chaining support (diff)
downloadlinux-3eed13fd933dbb81db12f7cdec6de9268c4443b5.tar.xz
linux-3eed13fd933dbb81db12f7cdec6de9268c4443b5.zip
Merge branch 'sglist-arch' into for-linus
Diffstat (limited to 'block')
-rw-r--r--block/ll_rw_blk.c41
1 files changed, 34 insertions, 7 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 4df7d027eb06..527bd8d4db50 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -30,6 +30,7 @@
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
#include <linux/fault-inject.h>
+#include <linux/scatterlist.h>
/*
* for max sense size
@@ -1318,9 +1319,10 @@ static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio,
* must make sure sg can hold rq->nr_phys_segments entries
*/
int blk_rq_map_sg(struct request_queue *q, struct request *rq,
- struct scatterlist *sg)
+ struct scatterlist *sglist)
{
struct bio_vec *bvec, *bvprv;
+ struct scatterlist *next_sg, *sg;
struct req_iterator iter;
int nsegs, cluster;
@@ -1331,11 +1333,12 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
* for each bio in rq
*/
bvprv = NULL;
+ sg = next_sg = &sglist[0];
rq_for_each_segment(bvec, rq, iter) {
int nbytes = bvec->bv_len;
if (bvprv && cluster) {
- if (sg[nsegs - 1].length + nbytes > q->max_segment_size)
+ if (sg->length + nbytes > q->max_segment_size)
goto new_segment;
if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
@@ -1343,14 +1346,15 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
goto new_segment;
- sg[nsegs - 1].length += nbytes;
+ sg->length += nbytes;
} else {
new_segment:
- memset(&sg[nsegs],0,sizeof(struct scatterlist));
- sg[nsegs].page = bvec->bv_page;
- sg[nsegs].length = nbytes;
- sg[nsegs].offset = bvec->bv_offset;
+ sg = next_sg;
+ next_sg = sg_next(sg);
+ sg->page = bvec->bv_page;
+ sg->length = nbytes;
+ sg->offset = bvec->bv_offset;
nsegs++;
}
bvprv = bvec;
@@ -4068,7 +4072,23 @@ static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
return queue_var_show(max_hw_sectors_kb, (page));
}
+static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(q->max_phys_segments, page);
+}
+
+static ssize_t queue_max_segments_store(struct request_queue *q,
+ const char *page, size_t count)
+{
+ unsigned long segments;
+ ssize_t ret = queue_var_store(&segments, page, count);
+ spin_lock_irq(q->queue_lock);
+ q->max_phys_segments = segments;
+ spin_unlock_irq(q->queue_lock);
+
+ return ret;
+}
static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
.show = queue_requests_show,
@@ -4092,6 +4112,12 @@ static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
.show = queue_max_hw_sectors_show,
};
+static struct queue_sysfs_entry queue_max_segments_entry = {
+ .attr = {.name = "max_segments", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_max_segments_show,
+ .store = queue_max_segments_store,
+};
+
static struct queue_sysfs_entry queue_iosched_entry = {
.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
.show = elv_iosched_show,
@@ -4103,6 +4129,7 @@ static struct attribute *default_attrs[] = {
&queue_ra_entry.attr,
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
+ &queue_max_segments_entry.attr,
&queue_iosched_entry.attr,
NULL,
};