Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  xen/blkfront: use blk_rq_map_sg to generate ring entries
  block: reduce stack footprint of blk_recount_segments()
  cciss: shorten 30s timeout on controller reset
  block: add documentation for register_blkdev()
  block: fix bogus gcc warning for uninitialized var usage

2 files changed, 22 insertions, 18 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index d2cb67b6117..b5a06111463 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -3611,11 +3611,15 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 		schedule_timeout_uninterruptible(30*HZ);
 
 		/* Now try to get the controller to respond to a no-op */
-		for (i=0; i<12; i++) {
+		for (i=0; i<30; i++) {
 			if (cciss_noop(pdev) == 0)
 				break;
-			else
-				printk("cciss: no-op failed%s\n", (i < 11 ? "; re-trying" : ""));
+
+			schedule_timeout_uninterruptible(HZ);
+		}
+		if (i == 30) {
+			printk(KERN_ERR "cciss: controller seems dead\n");
+			return -EBUSY;
 		}
 	}
 
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 918ef725de4..b6c8ce25435 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -40,6 +40,7 @@
 #include <linux/hdreg.h>
 #include <linux/cdrom.h>
 #include <linux/module.h>
+#include <linux/scatterlist.h>
 
 #include <xen/xenbus.h>
 #include <xen/grant_table.h>
@@ -82,6 +83,7 @@ struct blkfront_info
 	enum blkif_state connected;
 	int ring_ref;
 	struct blkif_front_ring ring;
+	struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 	unsigned int evtchn, irq;
 	struct request_queue *rq;
 	struct work_struct work;
@@ -204,12 +206,11 @@ static int blkif_queue_request(struct request *req)
 	struct blkfront_info *info = req->rq_disk->private_data;
 	unsigned long buffer_mfn;
 	struct blkif_request *ring_req;
-	struct req_iterator iter;
-	struct bio_vec *bvec;
 	unsigned long id;
 	unsigned int fsect, lsect;
-	int ref;
+	int i, ref;
 	grant_ref_t gref_head;
+	struct scatterlist *sg;
 
 	if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
 		return 1;
@@ -238,12 +239,13 @@ static int blkif_queue_request(struct request *req)
 	if (blk_barrier_rq(req))
 		ring_req->operation = BLKIF_OP_WRITE_BARRIER;
 
-	ring_req->nr_segments = 0;
-	rq_for_each_segment(bvec, req, iter) {
-		BUG_ON(ring_req->nr_segments == BLKIF_MAX_SEGMENTS_PER_REQUEST);
-		buffer_mfn = pfn_to_mfn(page_to_pfn(bvec->bv_page));
-		fsect = bvec->bv_offset >> 9;
-		lsect = fsect + (bvec->bv_len >> 9) - 1;
+	ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
+	BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+
+	for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
+		buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
+		fsect = sg->offset >> 9;
+		lsect = fsect + (sg->length >> 9) - 1;
 		/* install a grant reference. */
 		ref = gnttab_claim_grant_reference(&gref_head);
 		BUG_ON(ref == -ENOSPC);
@@ -254,16 +256,12 @@ static int blkif_queue_request(struct request *req)
 				buffer_mfn,
 				rq_data_dir(req) );
 
-		info->shadow[id].frame[ring_req->nr_segments] =
-				mfn_to_pfn(buffer_mfn);
-
-		ring_req->seg[ring_req->nr_segments] =
+		info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
+		ring_req->seg[i] =
 				(struct blkif_request_segment) {
 					.gref       = ref,
 					.first_sect = fsect,
 					.last_sect  = lsect };
-
-		ring_req->nr_segments++;
 	}
 
 	info->ring.req_prod_pvt++;
@@ -622,6 +620,8 @@ static int setup_blkring(struct xenbus_device *dev,
 	SHARED_RING_INIT(sring);
 	FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
 
+	sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+
 	err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
 	if (err < 0) {
 		free_page((unsigned long)sring);