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Commit b6c46cfa authored by Jens Axboe's avatar Jens Axboe
Browse files

Merge branch 'stable/for-jens-3.8' of... 

Merge branch 'stable/for-jens-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus

Konrad writes:

Please git pull the following branch:

 git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/for-jens-3.8

which has a bug-fix to the xen-blkfront and xen-blkback driver
when using the persistent mode. An issue was discovered where LVM
disks could not be read correctly and this fixes it. There
is also a change in llist.h which has been blessed by akpm.
parents 12c2bdb2 d62f6918

drivers/block/xen-blkback/blkback.c

+11 −7
Original line number Diff line number Diff line
@@ -161,10 +161,12 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 
static void make_response(struct xen_blkif *blkif, u64 id,

			  unsigned short op, int st);



#define foreach_grant(pos, rbtree, node) \

	for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node); \

#define foreach_grant_safe(pos, n, rbtree, node) \

	for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \

	     (n) = rb_next(&(pos)->node); \

	     &(pos)->node != NULL; \

	     (pos) = container_of(rb_next(&(pos)->node), typeof(*(pos)), node))

	     (pos) = container_of(n, typeof(*(pos)), node), \

	     (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL)





static void add_persistent_gnt(struct rb_root *root,
@@ -217,10 +219,11 @@ static void free_persistent_gnts(struct rb_root *root, unsigned int num) 
	struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];

	struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];

	struct persistent_gnt *persistent_gnt;

	struct rb_node *n;

	int ret = 0;

	int segs_to_unmap = 0;



	foreach_grant(persistent_gnt, root, node) {

	foreach_grant_safe(persistent_gnt, n, root, node) {

		BUG_ON(persistent_gnt->handle ==

			BLKBACK_INVALID_HANDLE);

		gnttab_set_unmap_op(&unmap[segs_to_unmap],
@@ -230,9 +233,6 @@ static void free_persistent_gnts(struct rb_root *root, unsigned int num) 
			persistent_gnt->handle);



		pages[segs_to_unmap] = persistent_gnt->page;

		rb_erase(&persistent_gnt->node, root);

		kfree(persistent_gnt);

		num--;



		if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||

			!rb_next(&persistent_gnt->node)) {
@@ -241,6 +241,10 @@ static void free_persistent_gnts(struct rb_root *root, unsigned int num) 
			BUG_ON(ret);

			segs_to_unmap = 0;

		}



		rb_erase(&persistent_gnt->node, root);

		kfree(persistent_gnt);

		num--;

	}

	BUG_ON(num != 0);

}

drivers/block/xen-blkfront.c

+6 −4
Original line number Diff line number Diff line
@@ -792,6 +792,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) 
{

	struct llist_node *all_gnts;

	struct grant *persistent_gnt;

	struct llist_node *n;



	/* Prevent new requests being issued until we fix things up. */

	spin_lock_irq(&info->io_lock);
@@ -804,7 +805,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) 
	/* Remove all persistent grants */

	if (info->persistent_gnts_c) {

		all_gnts = llist_del_all(&info->persistent_gnts);

		llist_for_each_entry(persistent_gnt, all_gnts, node) {

		llist_for_each_entry_safe(persistent_gnt, n, all_gnts, node) {

			gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);

			__free_page(pfn_to_page(persistent_gnt->pfn));

			kfree(persistent_gnt);
@@ -835,7 +836,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) 
static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,

			     struct blkif_response *bret)

{

	int i;

	int i = 0;

	struct bio_vec *bvec;

	struct req_iterator iter;

	unsigned long flags;
@@ -852,7 +853,8 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, 
		 */

		rq_for_each_segment(bvec, s->request, iter) {

			BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE);

			i = offset >> PAGE_SHIFT;

			if (bvec->bv_offset < offset)

				i++;

			BUG_ON(i >= s->req.u.rw.nr_segments);

			shared_data = kmap_atomic(

				pfn_to_page(s->grants_used[i]->pfn));
@@ -861,7 +863,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, 
				bvec->bv_len);

			bvec_kunmap_irq(bvec_data, &flags);

			kunmap_atomic(shared_data);

			offset += bvec->bv_len;

			offset = bvec->bv_offset + bvec->bv_len;

		}

	}

	/* Add the persistent grant into the list of free grants */

include/linux/llist.h

+25 −0
Original line number Diff line number Diff line
@@ -124,6 +124,31 @@ static inline void init_llist_head(struct llist_head *list) 
	     &(pos)->member != NULL;					\

	     (pos) = llist_entry((pos)->member.next, typeof(*(pos)), member))



/**

 * llist_for_each_entry_safe - iterate safely against remove over some entries

 * of lock-less list of given type.

 * @pos:	the type * to use as a loop cursor.

 * @n:		another type * to use as a temporary storage.

 * @node:	the fist entry of deleted list entries.

 * @member:	the name of the llist_node with the struct.

 *

 * In general, some entries of the lock-less list can be traversed

 * safely only after being removed from list, so start with an entry

 * instead of list head. This variant allows removal of entries

 * as we iterate.

 *

 * If being used on entries deleted from lock-less list directly, the

 * traverse order is from the newest to the oldest added entry.  If

 * you want to traverse from the oldest to the newest, you must

 * reverse the order by yourself before traversing.

 */

#define llist_for_each_entry_safe(pos, n, node, member)		\

	for ((pos) = llist_entry((node), typeof(*(pos)), member),	\

	     (n) = (pos)->member.next;					\

	     &(pos)->member != NULL;					\

	     (pos) = llist_entry(n, typeof(*(pos)), member),		\

	     (n) = (&(pos)->member != NULL) ? (pos)->member.next : NULL)



/**

 * llist_empty - tests whether a lock-less list is empty

 * @head:	the list to test