diff -ur -X exclude /opt/kernel/linux-2.5.1-pre6/drivers/block/elevator.c linux/drivers/block/elevator.c
--- /opt/kernel/linux-2.5.1-pre6/drivers/block/elevator.c	Fri Dec  7 02:09:30 2001
+++ linux/drivers/block/elevator.c	Fri Dec  7 09:27:29 2001
@@ -61,6 +61,12 @@
 	BUG_ON(next_rq->flags & REQ_STARTED);
 
 	/*
+	 * not a sector based request
+	 */
+	if (!(next_rq->flags & REQ_CMD))
+		return 0;
+
+	/*
 	 * if the device is different (not a normal case) just check if
 	 * bio is after rq
 	 */
@@ -95,6 +101,9 @@
  */
 inline int elv_rq_merge_ok(struct request *rq, struct bio *bio)
 {
+	if (!(rq->flags & REQ_CMD))
+		return 0;
+
 	/*
 	 * different data direction or already started, don't merge
 	 */
@@ -133,6 +142,8 @@
 			break;
 		if (__rq->flags & (REQ_BARRIER | REQ_STARTED))
 			break;
+		if (!(__rq->flags & REQ_CMD))
+			continue;
 
 		if (!*req && bio_rq_in_between(bio, __rq, &q->queue_head))
 			*req = __rq;
@@ -225,6 +236,9 @@
 
 		if (__rq->flags & (REQ_BARRIER | REQ_STARTED))
 			break;
+
+		if (!(__rq->flags & REQ_CMD))
+			continue;
 
 		if (!elv_rq_merge_ok(__rq, bio))
 			continue;
diff -ur -X exclude /opt/kernel/linux-2.5.1-pre6/drivers/block/ll_rw_blk.c linux/drivers/block/ll_rw_blk.c
--- /opt/kernel/linux-2.5.1-pre6/drivers/block/ll_rw_blk.c	Fri Dec  7 02:09:30 2001
+++ linux/drivers/block/ll_rw_blk.c	Fri Dec  7 09:30:16 2001
@@ -291,13 +291,13 @@
 	if (!(rq->flags & REQ_CMD))
 		return 0;
 
+	memset(rq->cmd, 0, sizeof(rq->cmd));
+
 	if (rq_data_dir(rq) == READ)
 		rq->cmd[0] = READ_10;
 	else 
 		rq->cmd[0] = WRITE_10;
 
-	rq->cmd[1] = 0;
-
 	/*
 	 * fill in lba
 	 */
@@ -305,7 +305,6 @@
 	rq->cmd[3] = (block >> 16) & 0xff;
 	rq->cmd[4] = (block >>  8) & 0xff;
 	rq->cmd[5] = block & 0xff;
-	rq->cmd[6] = 0;
 
 	/*
 	 * and transfer length
@@ -347,7 +346,7 @@
 	unsigned long long lastend;
 	struct bio_vec *bvec;
 	struct bio *bio;
-	int nsegs, i, cluster, j;
+	int nsegs, i, cluster;
 
 	nsegs = 0;
 	bio = rq->bio;
@@ -357,9 +356,7 @@
 	/*
 	 * for each bio in rq
 	 */
-	j = 0;
 	rq_for_each_bio(bio, rq) {
-		j++;
 		/*
 		 * for each segment in bio
 		 */
@@ -386,7 +383,6 @@
 new_segment:
 				if (nsegs > q->max_segments) {
 					printk("map: %d >= %d\n", nsegs, q->max_segments);
-					printk("map %d, %d, bio_sectors %d, vcnt %d\n", i, j, bio_sectors(bio), bio->bi_vcnt);
 					BUG();
 				}
 
@@ -411,7 +407,7 @@
 static inline int ll_new_segment(request_queue_t *q, struct request *req,
 				 struct bio *bio)
 {
-	if (req->nr_segments + bio->bi_vcnt < q->max_segments) {
+	if (req->nr_segments + bio->bi_vcnt <= q->max_segments) {
 		req->nr_segments += bio->bi_vcnt;
 		return 1;
 	}
@@ -480,9 +476,17 @@
  */
 static inline void __generic_unplug_device(request_queue_t *q)
 {
-	if (test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
-		if (!elv_queue_empty(q))
-			q->request_fn(q);
+	/*
+	 * not plugged
+	 */
+	if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+		return;
+
+	/*
+	 * was plugged, fire request_fn if queue has stuff to do
+	 */
+	if (!elv_queue_empty(q))
+		q->request_fn(q);
 }
 
 /**
diff -ur -X exclude /opt/kernel/linux-2.5.1-pre6/fs/bio.c linux/fs/bio.c
--- /opt/kernel/linux-2.5.1-pre6/fs/bio.c	Fri Dec  7 02:09:31 2001
+++ linux/fs/bio.c	Fri Dec  7 09:59:52 2001
@@ -377,7 +377,7 @@
 		/*
 		 * iterate iovec list and alloc pages + copy data
 		 */
-		bio_for_each_segment(bv, bio, i) {
+		__bio_for_each_segment(bv, bio, i, 0) {
 			struct bio_vec *bbv = &b->bi_io_vec[i];
 			char *vfrom, *vto;
 
@@ -392,8 +392,7 @@
 				vfrom = kmap(bv->bv_page);
 				vto = kmap(bbv->bv_page);
 			} else {
-				__save_flags(flags);
-				__cli();
+				local_irq_save(flags);
 				vfrom = kmap_atomic(bv->bv_page, KM_BIO_IRQ);
 				vto = kmap_atomic(bbv->bv_page, KM_BIO_IRQ);
 			}
@@ -405,7 +404,7 @@
 			} else {
 				kunmap_atomic(vto, KM_BIO_IRQ);
 				kunmap_atomic(vfrom, KM_BIO_IRQ);
-				__restore_flags(flags);
+				local_irq_restore(flags);
 			}
 
 fill_in:
@@ -424,10 +423,8 @@
 	return b;
 
 oom:
-	while (i >= 0) {
+	while (--i >= 0)
 		__free_page(b->bi_io_vec[i].bv_page);
-		i--;
-	}
 
 	bio_pool_put(b);
 	return NULL;
@@ -613,6 +610,11 @@
 	if (err)
 		kio->errno = err;
 
+	/*
+	 * final atomic_dec of io_count to match our initial setting of 1.
+	 * I/O may or may not have completed at this point, final completion
+	 * handler is only run on last decrement.
+	 */
 	end_kio_request(kio, !err);
 }
 
diff -ur -X exclude /opt/kernel/linux-2.5.1-pre6/include/linux/bio.h linux/include/linux/bio.h
--- /opt/kernel/linux-2.5.1-pre6/include/linux/bio.h	Fri Dec  7 02:09:31 2001
+++ linux/include/linux/bio.h	Fri Dec  7 10:14:18 2001
@@ -100,7 +100,6 @@
 #define bio_iovec_idx(bio, idx)	(&((bio)->bi_io_vec[(idx)]))
 #define bio_iovec(bio)		bio_iovec_idx((bio), (bio)->bi_idx)
 #define bio_page(bio)		bio_iovec((bio))->bv_page
-#define __bio_offset(bio, idx)	bio_iovec_idx((bio), (idx))->bv_offset
 #define bio_offset(bio)		bio_iovec((bio))->bv_offset
 #define bio_sectors(bio)	((bio)->bi_size >> 9)
 #define bio_data(bio)		(page_address(bio_page((bio))) + bio_offset((bio)))
@@ -136,10 +135,17 @@
 
 #define bio_io_error(bio) bio_endio((bio), 0, bio_sectors((bio)))
 
-#define bio_for_each_segment(bvl, bio, i)				\
-	for (bvl = bio_iovec((bio)), i = (bio)->bi_idx;			\
+/*
+ * drivers should not use the __ version unless they _really_ want to
+ * run through the entire bio and not just pending pieces
+ */
+#define __bio_for_each_segment(bvl, bio, i, start_idx)			\
+	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);	\
 	     i < (bio)->bi_vcnt;					\
 	     bvl++, i++)
+
+#define bio_for_each_segment(bvl, bio, i)				\
+	__bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 
 /*
  * get a reference to a bio, so it won't disappear. the intended use is
diff -ur -X exclude /opt/kernel/linux-2.5.1-pre6/mm/highmem.c linux/mm/highmem.c
--- /opt/kernel/linux-2.5.1-pre6/mm/highmem.c	Fri Dec  7 09:16:24 2001
+++ linux/mm/highmem.c	Fri Dec  7 10:28:44 2001
@@ -214,7 +214,7 @@
 	struct bio_vec *tovec, *fromvec;
 	int i;
 
-	bio_for_each_segment(tovec, to, i) {
+	__bio_for_each_segment(tovec, to, i, 0) {
 		fromvec = &from->bi_io_vec[i];
 
 		/*
@@ -225,12 +225,11 @@
 
 		vfrom = page_address(fromvec->bv_page) + fromvec->bv_offset;
 
-		__save_flags(flags);
-		__cli();
+		local_irq_save(flags);
 		vto = kmap_atomic(tovec->bv_page, KM_BOUNCE_READ);
-		memcpy(vto + tovec->bv_offset, vfrom, to->bi_size);
+		memcpy(vto + tovec->bv_offset, vfrom, tovec->bv_len);
 		kunmap_atomic(vto, KM_BOUNCE_READ);
-		__restore_flags(flags);
+		local_irq_restore(flags);
 	}
 }
 
@@ -263,28 +262,39 @@
 static inline int bounce_end_io (struct bio *bio, int nr_sectors)
 {
 	struct bio *bio_orig = bio->bi_private;
-	struct page *page = bio_page(bio);
+	struct bio_vec *bvec, *org_vec;
 	unsigned long flags;
-	int ret;
+	int ret, i;
 
-	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
-		set_bit(BIO_UPTODATE, &bio_orig->bi_flags);
+	if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+		goto out_eio;
 
-	ret = bio_orig->bi_end_io(bio_orig, nr_sectors);
+	set_bit(BIO_UPTODATE, &bio_orig->bi_flags);
 
+	/*
+	 * free up bounce indirect pages used
+	 */
 	spin_lock_irqsave(&emergency_lock, flags);
-	if (nr_emergency_pages >= POOL_SIZE) {
-		spin_unlock_irqrestore(&emergency_lock, flags);
-		__free_page(page);
-	} else {
-		/*
-		 * We are abusing page->list to manage
-		 * the highmem emergency pool:
-		 */
-		list_add(&page->list, &emergency_pages);
-		nr_emergency_pages++;
-		spin_unlock_irqrestore(&emergency_lock, flags);
+	__bio_for_each_segment(bvec, bio, i, 0) {
+		org_vec = &bio_orig->bi_io_vec[i];
+		if (bvec->bv_page == org_vec->bv_page)
+			continue;
+	
+		if (nr_emergency_pages >= POOL_SIZE)
+			__free_page(bvec->bv_page);
+		else {
+			/*
+			 * We are abusing page->list to manage
+			 * the highmem emergency pool:
+			 */
+			list_add(&bvec->bv_page->list, &emergency_pages);
+			nr_emergency_pages++;
+		}
 	}
+	spin_unlock_irqrestore(&emergency_lock, flags);
+
+out_eio:
+	ret = bio_orig->bi_end_io(bio_orig, nr_sectors);
 
 	bio_put(bio);
 	return ret;