[Xen-devel] [PATCH] xen-blkfront: drop the use of llist_for_each_entry_safe

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Replace llist_for_each_entry_safe with a while loop and
llist_del_first.

llist_for_each_entry_safe can trigger a bug in GCC 4.1, so it's best
to remove it and use a while loop and llist_del_first (which is
already in llist.h).

Since xen-blkfront is the only user of the llist_for_each_entry_safe
macro remove it from llist.h.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxx
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 drivers/block/xen-blkfront.c |    5 ++---
 include/linux/llist.h        |   25 -------------------------
 2 files changed, 2 insertions(+), 28 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 11043c1..c325062 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -790,7 +790,6 @@ static void blkif_restart_queue(struct work_struct *work)
 
 static void blkif_free(struct blkfront_info *info, int suspend)
 {
-       struct llist_node *all_gnts;
        struct grant *persistent_gnt;
        struct llist_node *n;
 
@@ -804,8 +803,8 @@ 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_safe(persistent_gnt, n, all_gnts, node) {
+               while ((n = llist_del_first(&info->persistent_gnts)) != NULL) {
+                       persistent_gnt = llist_entry(n, struct grant, node);
                        gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
                        __free_page(pfn_to_page(persistent_gnt->pfn));
                        kfree(persistent_gnt);
diff --git a/include/linux/llist.h b/include/linux/llist.h
index d0ab98f..a5199f6 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -125,31 +125,6 @@ static inline void init_llist_head(struct llist_head *list)
             (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
  *
-- 
1.7.7.5 (Apple Git-26)


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