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.
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 74374fb..5ac841f 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -161,10 +161,12 @@
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 @@
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 @@
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 @@
BUG_ON(ret);
segs_to_unmap = 0;
}
+
+ rb_erase(&persistent_gnt->node, root);
+ kfree(persistent_gnt);
+ num--;
}
BUG_ON(num != 0);
}
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 96e9b00..11043c1 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -792,6 +792,7 @@
{
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 @@
/* 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_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 @@
*/
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 @@
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 */
diff --git a/include/linux/llist.h b/include/linux/llist.h
index a5199f6..d0ab98f 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -125,6 +125,31 @@
(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
*