xen-blkfront: use a different scatterlist for each request

[karo-tx-linux.git] / drivers / block / xen-blkfront.c

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 82d63d5b1750d1ac8c54f7c366edceae36367a9a..bac8cf31319b6b269840bd03583679c0cb4aec78 100644 (file)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -76,6 +76,7 @@ struct blk_shadow {
        struct request *request;
        struct grant **grants_used;
        struct grant **indirect_grants;
+       struct scatterlist *sg;
 };
 
 struct split_bio {
@@ -113,7 +114,6 @@ struct blkfront_info
        enum blkif_state connected;
        int ring_ref;
        struct blkif_front_ring ring;
-       struct scatterlist *sg;
        unsigned int evtchn, irq;
        struct request_queue *rq;
        struct work_struct work;
@@ -438,7 +438,7 @@ static int blkif_queue_request(struct request *req)
                       req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
                BUG_ON(info->max_indirect_segments &&
                       req->nr_phys_segments > info->max_indirect_segments);
-               nseg = blk_rq_map_sg(req->q, req, info->sg);
+               nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
                ring_req->u.rw.id = id;
                if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
                        /*
@@ -469,7 +469,7 @@ static int blkif_queue_request(struct request *req)
                        }
                        ring_req->u.rw.nr_segments = nseg;
                }
-               for_each_sg(info->sg, sg, nseg, i) {
+               for_each_sg(info->shadow[id].sg, sg, nseg, i) {
                        fsect = sg->offset >> 9;
                        lsect = fsect + (sg->length >> 9) - 1;
 
@@ -914,8 +914,6 @@ static void blkif_free(struct blkfront_info *info, int suspend)
        }
        BUG_ON(info->persistent_gnts_c != 0);
 
-       kfree(info->sg);
-       info->sg = NULL;
        for (i = 0; i < BLK_RING_SIZE; i++) {
                /*
                 * Clear persistent grants present in requests already
@@ -953,6 +951,8 @@ free_shadow:
                info->shadow[i].grants_used = NULL;
                kfree(info->shadow[i].indirect_grants);
                info->shadow[i].indirect_grants = NULL;
+               kfree(info->shadow[i].sg);
+               info->shadow[i].sg = NULL;
        }
 
        /* No more gnttab callback work. */
@@ -979,12 +979,9 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
                             struct blkif_response *bret)
 {
        int i = 0;
-       struct bio_vec *bvec;
-       struct req_iterator iter;
-       unsigned long flags;
+       struct scatterlist *sg;
        char *bvec_data;
        void *shared_data;
-       unsigned int offset = 0;
        int nseg;
 
        nseg = s->req.operation == BLKIF_OP_INDIRECT ?
@@ -997,19 +994,16 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
                 * than PAGE_SIZE, we have to keep track of the current offset,
                 * to be sure we are copying the data from the right shared page.
                 */
-               rq_for_each_segment(bvec, s->request, iter) {
-                       BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE);
-                       if (bvec->bv_offset < offset)
-                               i++;
-                       BUG_ON(i >= nseg);
+               for_each_sg(s->sg, sg, nseg, i) {
+                       BUG_ON(sg->offset + sg->length > PAGE_SIZE);
                        shared_data = kmap_atomic(
                                pfn_to_page(s->grants_used[i]->pfn));
-                       bvec_data = bvec_kmap_irq(bvec, &flags);
-                       memcpy(bvec_data, shared_data + bvec->bv_offset,
-                               bvec->bv_len);
-                       bvec_kunmap_irq(bvec_data, &flags);
+                       bvec_data = kmap_atomic(sg_page(sg));
+                       memcpy(bvec_data   + sg->offset,
+                              shared_data + sg->offset,
+                              sg->length);
+                       kunmap_atomic(bvec_data);
                        kunmap_atomic(shared_data);
-                       offset = bvec->bv_offset + bvec->bv_len;
                }
        }
        /* Add the persistent grant into the list of free grants */
@@ -1656,10 +1650,6 @@ static int blkfront_setup_indirect(struct blkfront_info *info)
                                                  xen_blkif_max_segments);
                segs = info->max_indirect_segments;
        }
-       info->sg = kzalloc(sizeof(info->sg[0]) * segs, GFP_KERNEL);
-       if (info->sg == NULL)
-               goto out_of_memory;
-       sg_init_table(info->sg, segs);
 
        err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE);
        if (err)
@@ -1669,26 +1659,29 @@ static int blkfront_setup_indirect(struct blkfront_info *info)
                info->shadow[i].grants_used = kzalloc(
                        sizeof(info->shadow[i].grants_used[0]) * segs,
                        GFP_NOIO);
+               info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO);
                if (info->max_indirect_segments)
                        info->shadow[i].indirect_grants = kzalloc(
                                sizeof(info->shadow[i].indirect_grants[0]) *
                                INDIRECT_GREFS(segs),
                                GFP_NOIO);
                if ((info->shadow[i].grants_used == NULL) ||
+                       (info->shadow[i].sg == NULL) ||
                     (info->max_indirect_segments &&
                     (info->shadow[i].indirect_grants == NULL)))
                        goto out_of_memory;
+               sg_init_table(info->shadow[i].sg, segs);
        }
 
 
        return 0;
 
 out_of_memory:
-       kfree(info->sg);
-       info->sg = NULL;
        for (i = 0; i < BLK_RING_SIZE; i++) {
                kfree(info->shadow[i].grants_used);
                info->shadow[i].grants_used = NULL;
+               kfree(info->shadow[i].sg);
+               info->shadow[i].sg = NULL;
                kfree(info->shadow[i].indirect_grants);
                info->shadow[i].indirect_grants = NULL;
        }