static void init_request_from_bio(struct request *req, struct bio *bio);
static int __make_request(struct request_queue *q, struct bio *bio);
static struct io_context *current_io_context(gfp_t gfp_flags, int node);
+static void blk_recalc_rq_segments(struct request *rq);
/*
* For the allocated request tables
*/
return;
- if (unlikely(!__test_and_clear_bit(tag, bqt->tag_map))) {
- printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
- __FUNCTION__, tag);
- return;
- }
-
list_del_init(&rq->queuelist);
rq->cmd_flags &= ~REQ_QUEUED;
rq->tag = -1;
__FUNCTION__, tag);
bqt->tag_index[tag] = NULL;
+
+ /*
+ * We use test_and_clear_bit's memory ordering properties here.
+ * The tag_map bit acts as a lock for tag_index[bit], so we need
+ * a barrer before clearing the bit (precisely: release semantics).
+ * Could use clear_bit_unlock when it is merged.
+ */
+ if (unlikely(!test_and_clear_bit(tag, bqt->tag_map))) {
+ printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
+ __FUNCTION__, tag);
+ return;
+ }
+
bqt->busy--;
}
return 1;
} while (test_and_set_bit(tag, bqt->tag_map));
+ /*
+ * We rely on test_and_set_bit providing lock memory ordering semantics
+ * (could use test_and_set_bit_lock when it is merged).
+ */
rq->cmd_flags |= REQ_QUEUED;
rq->tag = tag;
void blk_recount_segments(struct request_queue *q, struct bio *bio)
{
+ struct request rq;
+ struct bio *nxt = bio->bi_next;
+ rq.q = q;
+ rq.bio = rq.biotail = bio;
+ bio->bi_next = NULL;
+ blk_recalc_rq_segments(&rq);
+ bio->bi_next = nxt;
+ bio->bi_phys_segments = rq.nr_phys_segments;
+ bio->bi_hw_segments = rq.nr_hw_segments;
+ bio->bi_flags |= (1 << BIO_SEG_VALID);
+}
+EXPORT_SYMBOL(blk_recount_segments);
+
+static void blk_recalc_rq_segments(struct request *rq)
+{
+ int nr_phys_segs;
+ int nr_hw_segs;
+ unsigned int phys_size;
+ unsigned int hw_size;
struct bio_vec *bv, *bvprv = NULL;
- int i, nr_phys_segs, nr_hw_segs, seg_size, hw_seg_size, cluster;
+ int seg_size;
+ int hw_seg_size;
+ int cluster;
+ struct req_iterator iter;
int high, highprv = 1;
+ struct request_queue *q = rq->q;
- if (unlikely(!bio->bi_io_vec))
+ if (!rq->bio)
return;
cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
- hw_seg_size = seg_size = nr_phys_segs = nr_hw_segs = 0;
- bio_for_each_segment(bv, bio, i) {
+ hw_seg_size = seg_size = 0;
+ phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
+ rq_for_each_segment(bv, rq, iter) {
/*
* the trick here is making sure that a high page is never
* considered part of another segment, since that might
}
new_segment:
if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) &&
- !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) {
+ !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
hw_seg_size += bv->bv_len;
- } else {
+ else {
new_hw_segment:
- if (hw_seg_size > bio->bi_hw_front_size)
- bio->bi_hw_front_size = hw_seg_size;
+ if (nr_hw_segs == 1 &&
+ hw_seg_size > rq->bio->bi_hw_front_size)
+ rq->bio->bi_hw_front_size = hw_seg_size;
hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len;
nr_hw_segs++;
}
seg_size = bv->bv_len;
highprv = high;
}
- if (hw_seg_size > bio->bi_hw_back_size)
- bio->bi_hw_back_size = hw_seg_size;
- if (nr_hw_segs == 1 && hw_seg_size > bio->bi_hw_front_size)
- bio->bi_hw_front_size = hw_seg_size;
- bio->bi_phys_segments = nr_phys_segs;
- bio->bi_hw_segments = nr_hw_segs;
- bio->bi_flags |= (1 << BIO_SEG_VALID);
+
+ if (nr_hw_segs == 1 &&
+ hw_seg_size > rq->bio->bi_hw_front_size)
+ rq->bio->bi_hw_front_size = hw_seg_size;
+ if (hw_seg_size > rq->biotail->bi_hw_back_size)
+ rq->biotail->bi_hw_back_size = hw_seg_size;
+ rq->nr_phys_segments = nr_phys_segs;
+ rq->nr_hw_segments = nr_hw_segs;
}
-EXPORT_SYMBOL(blk_recount_segments);
static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
struct bio *nxt)
struct scatterlist *sg)
{
struct bio_vec *bvec, *bvprv;
- struct bio *bio;
- int nsegs, i, cluster;
+ struct req_iterator iter;
+ int nsegs, cluster;
nsegs = 0;
cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
* for each bio in rq
*/
bvprv = NULL;
- rq_for_each_bio(bio, rq) {
- /*
- * for each segment in bio
- */
- bio_for_each_segment(bvec, bio, i) {
+ rq_for_each_segment(bvec, rq, iter) {
int nbytes = bvec->bv_len;
if (bvprv && cluster) {
nsegs++;
}
bvprv = bvec;
- } /* segments in bio */
- } /* bios in rq */
+ } /* segments in rq */
return nsegs;
}
EXPORT_SYMBOL(submit_bio);
-static void blk_recalc_rq_segments(struct request *rq)
-{
- struct bio *bio, *prevbio = NULL;
- int nr_phys_segs, nr_hw_segs;
- unsigned int phys_size, hw_size;
- struct request_queue *q = rq->q;
-
- if (!rq->bio)
- return;
-
- phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
- rq_for_each_bio(bio, rq) {
- /* Force bio hw/phys segs to be recalculated. */
- bio->bi_flags &= ~(1 << BIO_SEG_VALID);
-
- nr_phys_segs += bio_phys_segments(q, bio);
- nr_hw_segs += bio_hw_segments(q, bio);
- if (prevbio) {
- int pseg = phys_size + prevbio->bi_size + bio->bi_size;
- int hseg = hw_size + prevbio->bi_size + bio->bi_size;
-
- if (blk_phys_contig_segment(q, prevbio, bio) &&
- pseg <= q->max_segment_size) {
- nr_phys_segs--;
- phys_size += prevbio->bi_size + bio->bi_size;
- } else
- phys_size = 0;
-
- if (blk_hw_contig_segment(q, prevbio, bio) &&
- hseg <= q->max_segment_size) {
- nr_hw_segs--;
- hw_size += prevbio->bi_size + bio->bi_size;
- } else
- hw_size = 0;
- }
- prevbio = bio;
- }
-
- rq->nr_phys_segments = nr_phys_segs;
- rq->nr_hw_segments = nr_hw_segs;
-}
-
static void blk_recalc_rq_sectors(struct request *rq, int nsect)
{
if (blk_fs_request(rq)) {
projects / linux-2.6-block.git / blobdiff