This adds a pointer, next_rq, to the request structure for the second
data phase (e.g. for bidi).
We need bidi support for block pc requests, special requests, etc so
instead of introducing REQ_TYPE_BIDI, a bidi requests simply set a
req->next_rq pointer. linked request support can be used for other
stuff REQ_BIDI might be nice for the future.
A bidi request uses two request structures (one in request and one out
request). The in request is linked and the out request is en-queued.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
block/ll_rw_blk.c | 1 +
include/linux/blkdev.h | 4 ++++
2 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 123003a..9b799ee 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -256,6 +256,7 @@ static void rq_init(request_queue_t *q,
rq->end_io = NULL;
rq->end_io_data = NULL;
rq->completion_data = NULL;
+ rq->next_rq = NULL;
}
/**
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a686eab..5234d17 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -314,6 +314,9 @@ struct request {
*/
rq_end_io_fn *end_io;
void *end_io_data;
+
+ /* for bidi */
+ struct request *next_rq;
};
/*
@@ -543,6 +546,7 @@ #define blk_pm_request(rq) \
#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
+#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
--
1.4.3.2
-
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