diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/ll_rw_blk.c | 41 |
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, }; |