This patch converts bidi of scsi mid-layer to use blk_end_request().
rq->next_rq represents a pair of bidi requests.
(There are no other use of 'next_rq' of struct request.)
For both requests in the pair, end_that_request_chunk() should be
called before end_that_request_last() is called for one of them.
Since the calls to end_that_request_first()/chunk() and
end_that_request_last() are packaged into blk_end_request(),
the handling of next_rq completion has to be moved into
blk_end_request(), too.
Bidi sets its specific value to rq->data_len before the request is
completed so that upper-layer can read it.
This setting must be between end_that_request_chunk() and
end_that_request_last(), because rq->data_len may be used
in end_that_request_chunk() by blk_trace and so on.
To satisfy the requirement, use blk_end_request_callback() which
is added in PATCH 25 only for the tricky drivers.
If bidi didn't reuse rq->data_len and added new members to request
for the specific value, it could set before end_that_request_chunk()
and use the standard blk_end_request() like below.
void scsi_end_bidi_request(struct scsi_cmnd *cmd)
{
struct request *req = cmd->request;
rq->resid = scsi_out(cmd)->resid;
rq->next_rq->resid = scsi_in(cmd)->resid;
if (blk_end_request(req, 1, req->data_len))
BUG();
scsi_release_buffers(cmd);
scsi_next_command(cmd);
}
Signed-off-by: Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx>
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
---
block/ll_rw_blk.c | 18 +++++++++++++
drivers/scsi/scsi_lib.c | 66 ++++++++++++++++++++++++------------------------
2 files changed, 52 insertions(+), 32 deletions(-)
Index: 2.6.24-rc3-mm2/drivers/scsi/scsi_lib.c
===================================================================
--- 2.6.24-rc3-mm2.orig/drivers/scsi/scsi_lib.c
+++ 2.6.24-rc3-mm2/drivers/scsi/scsi_lib.c
@@ -629,28 +629,6 @@ void scsi_run_host_queues(struct Scsi_Ho
scsi_run_queue(sdev->request_queue);
}
-static void scsi_finalize_request(struct scsi_cmnd *cmd, int uptodate)
-{
- struct request_queue *q = cmd->device->request_queue;
- struct request *req = cmd->request;
- unsigned long flags;
-
- add_disk_randomness(req->rq_disk);
-
- spin_lock_irqsave(q->queue_lock, flags);
- if (blk_rq_tagged(req))
- blk_queue_end_tag(q, req);
-
- end_that_request_last(req, uptodate);
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- /*
- * This will goose the queue request function at the end, so we don't
- * need to worry about launching another command.
- */
- scsi_next_command(cmd);
-}
-
/*
* Function: scsi_end_request()
*
@@ -921,6 +899,20 @@ void scsi_release_buffers(struct scsi_cm
EXPORT_SYMBOL(scsi_release_buffers);
/*
+ * Called from blk_end_request_callback() after all DATA in rq and its next_rq
+ * are completed before rq is completed/freed.
+ */
+static int scsi_end_bidi_request_cb(struct request *rq)
+{
+ struct scsi_cmnd *cmd = rq->special;
+
+ rq->data_len = scsi_out(cmd)->resid;
+ rq->next_rq->data_len = scsi_in(cmd)->resid;
+
+ return 0;
+}
+
+/*
* Bidi commands Must be complete as a whole, both sides at once.
* If part of the bytes were written and lld returned
* scsi_in()->resid and/or scsi_out()->resid this information will be left
@@ -931,22 +923,32 @@ void scsi_end_bidi_request(struct scsi_c
{
struct request *req = cmd->request;
- end_that_request_chunk(req, 1, req->data_len);
- req->data_len = scsi_out(cmd)->resid;
-
- end_that_request_chunk(req->next_rq, 1, req->next_rq->data_len);
- req->next_rq->data_len = scsi_in(cmd)->resid;
-
- scsi_release_buffers(cmd);
-
/*
*FIXME: If ll_rw_blk.c is changed to also put_request(req->next_rq)
- * in end_that_request_last() then this WARN_ON must be removed.
+ * in blk_end_request() then this WARN_ON must be removed.
* for now, upper-driver must have registered an end_io.
*/
WARN_ON(!req->end_io);
- scsi_finalize_request(cmd, 1);
+ /*
+ * blk_end_request() family take care of data completion of next_rq.
+ *
+ * req->data_len and req->next_rq->data_len must be set after
+ * all data are completed, since they may be referenced during
+ * the data completion process.
+ * So use the callback feature of blk_end_request() here.
+ *
+ * NOTE: If bidi doesn't reuse the data_len field for upper-layer's
+ * reference (e.g. adds new members for it to struct request),
+ * we can use the standard blk_end_request() interface here.
+ */
+ if (blk_end_request_callback(req, 1, req->data_len,
+ scsi_end_bidi_request_cb))
+ /* req has not been completed */
+ BUG();
+
+ scsi_release_buffers(cmd);
+ scsi_next_command(cmd);
}
/*
Index: 2.6.24-rc3-mm2/block/ll_rw_blk.c
===================================================================
--- 2.6.24-rc3-mm2.orig/block/ll_rw_blk.c
+++ 2.6.24-rc3-mm2/block/ll_rw_blk.c
@@ -3817,6 +3817,12 @@ int blk_end_request(struct request *rq,
if (blk_fs_request(rq) || blk_pc_request(rq)) {
if (__end_that_request_first(rq, uptodate, nr_bytes))
return 1;
+
+ /* Bidi request must be completed as a whole */
+ if (blk_bidi_rq(rq) &&
+ __end_that_request_first(rq->next_rq, uptodate,
+ blk_rq_bytes(rq->next_rq)))
+ return 1;
}
add_disk_randomness(rq->rq_disk);
@@ -3840,6 +3846,12 @@ int __blk_end_request(struct request *rq
if (blk_fs_request(rq) || blk_pc_request(rq)) {
if (__end_that_request_first(rq, uptodate, nr_bytes))
return 1;
+
+ /* Bidi request must be completed as a whole */
+ if (blk_bidi_rq(rq) &&
+ __end_that_request_first(rq->next_rq, uptodate,
+ blk_rq_bytes(rq->next_rq)))
+ return 1;
}
add_disk_randomness(rq->rq_disk);
@@ -3884,6 +3896,12 @@ int blk_end_request_callback(struct requ
if (blk_fs_request(rq) || blk_pc_request(rq)) {
if (__end_that_request_first(rq, uptodate, nr_bytes))
return 1;
+
+ /* Bidi request must be completed as a whole */
+ if (blk_bidi_rq(rq) &&
+ __end_that_request_first(rq->next_rq, uptodate,
+ blk_rq_bytes(rq->next_rq)))
+ return 1;
}
/* Special feature for tricky drivers */
--
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