3 files changed, 17 insertions, 4 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5a4d39b4686b..5aa372a7380c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -216,9 +216,9 @@ static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
 }
 
 #define for_each_bvec(bvl, bio_vec, iter, start)                        \
-        for ((iter) = start;                                            \
-             (bvl) = bvec_iter_bvec((bio_vec), (iter)),                 \
-                (iter).bi_size;                                         \
+        for (iter = (start);                                            \
+             (iter).bi_size &&                                          \
+                ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
              bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
 
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index bbc3a6c88fce..aa0eaa2d0bd8 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -189,6 +189,7 @@ enum rq_flag_bits {
         __REQ_KERNEL,           /* direct IO to kernel pages */
         __REQ_PM,               /* runtime pm request */
         __REQ_END,              /* last of chain of requests */
+        __REQ_HASHED,           /* on IO scheduler merge hash */
         __REQ_NR_BITS,          /* stops here */
 };
 
@@ -241,5 +242,6 @@ enum rq_flag_bits {
 #define REQ_KERNEL              (1ULL << __REQ_KERNEL)
 #define REQ_PM                  (1ULL << __REQ_PM)
 #define REQ_END                 (1ULL << __REQ_END)
+#define REQ_HASHED              (1ULL << __REQ_HASHED)
 
 #endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1e1fa3f93d5f..99617cf7dd1a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -118,7 +118,18 @@ struct request {
         struct bio *bio;
         struct bio *biotail;
 
-        struct hlist_node hash; /* merge hash */
+        /*
+         * The hash is used inside the scheduler, and killed once the
+         * request reaches the dispatch list. The ipi_list is only used
+         * to queue the request for softirq completion, which is long
+         * after the request has been unhashed (and even removed from
+         * the dispatch list).
+         */
+        union {
+                struct hlist_node hash; /* merge hash */
+                struct list_head ipi_list;
+        };
+
         /*
          * The rb_node is only used inside the io scheduler, requests
          * are pruned when moved to the dispatch queue. So let the