On 10/23/2017 5:51 PM, Christoph Hellwig wrote:
This helpers allows to bounce steal the uncompleted bios from a request so
that they can be reissued on another path.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
---
block/blk-core.c | 20 ++++++++++++++++++++
include/linux/blkdev.h | 2 ++
2 files changed, 22 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index b8c80f39f5fe..e804529e65a5 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2767,6 +2767,26 @@ struct request *blk_fetch_request(struct request_queue *q)
}
EXPORT_SYMBOL(blk_fetch_request);
+/*
+ * Steal bios from a request. The request must not have been partially
+ * completed before.
+ */
Maybe we can add to the comment that "list" is the destination for the
stolen bio.
+void blk_steal_bios(struct bio_list *list, struct request *rq)
+{
+ if (rq->bio) {
+ if (list->tail)
+ list->tail->bi_next = rq->bio;
+ else
+ list->head = rq->bio;
+ list->tail = rq->biotail;
if list->tail != NULL don't we lose the "list->tail->bi_next = rq->bio;"
assignment after assigning "list->tail = rq->biotail;" ?
+ }
+
+ rq->bio = NULL;
we can add this NULL assignment inside the big "if", but I'm not sure
regarding the next 2 assignments.
Anyway not a big deal.
+ rq->biotail = NULL;
+ rq->__data_len = 0;
+}
+EXPORT_SYMBOL_GPL(blk_steal_bios);
+
