Hi Boaz, Jens,
On Thu, 06 Dec 2007 11:24:44 +0200, Boaz Harrosh <bharrosh@xxxxxxxxxxx> wrote:
> > 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 +923,28 @@ 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.
> > + * blk_end_request() family use next_rq->data_len for
> > + * the completion data size of next_rq.
> > + * So resid can't be set before the data completion of next_rq
> > + * in blk_end_request().
> > + * To resolve that, use the callback feature of blk_end_request().
> > + */
> > + 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 */
>
> No I don't like it. The only client left for blk_end_request_callback()
> is bidi,
ide-cd (cdrom_newpc_intr) is another client.
So I can't drop blk_end_request_callback() even if bidi doesn't use it.
> and for bidi we can do a much simpler thing. listed below
> are some possible solutions.
>
> 1. Take extra parm to blk_end_request like
> int blk_end_request(struct request *rq, int error, int nr_bytes, int bidi_bytes)
>
> if the bidi_bytes is not zero than req->next_req is freed like above.
OK, I agree with the interface basically.
I didn't like to have the 'bidi_bytes', since I considered it was
a driver specific argument and I prefer to avoid driver specific
interface like blk_end_request_callback() as much as possible.
However, it can be considered as block-layer generic, since next_rq is
a member of struct request (and other drivers might have bidi support
although scsi is only one user right now).
So I made a tentative patch below, which adds a variant,
blk_end_bidi_request().
Please take a look.
> And please reconsider that double implementation. (triple above, but I hope
> now I have convinced you to drop one). Jense please ?
I have a plan to remove that duplication using the internal-with-flags
implementation something like the patch (blk_end_io) below.
Jens,
If you agree with passing a 'needlock' flag, which is used to decide
whether to get queue's lock, I can remove the last duplication of
__blk_end_request() too. Do you still disagree?
Thanks,
Kiyoshi Ueda
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()
*
@@ -930,23 +908,25 @@ EXPORT_SYMBOL(scsi_release_buffers);
void scsi_end_bidi_request(struct scsi_cmnd *cmd)
{
struct request *req = cmd->request;
+ unsigned int dlen = req->data_len;
+ unsigned int next_dlen = req->next_rq->data_len;
- 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_bidi_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);
+ if (blk_end_bidi_request(req, 1, dlen, next_dlen))
+ /* 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
@@ -3792,24 +3792,17 @@ static void complete_request(struct requ
if (!list_empty(&rq->queuelist))
blkdev_dequeue_request(rq);
+ if (blk_bidi_rq(rq) && !rq->end_io)
+ __blk_put_request(rq->next_rq->q, rq->next_rq);
+
end_that_request_last(rq, uptodate);
}
-/**
- * blk_end_request - Helper function for drivers to complete the request.
- * @rq: the request being processed
- * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
- * @nr_bytes: number of bytes to complete
- *
- * Description:
- * Ends I/O on a number of bytes attached to @rq.
- * If @rq has leftover, sets it up for the next range of segments.
- *
- * Return:
- * 0 - we are done with this request
- * 1 - still buffers pending for this request
- **/
-int blk_end_request(struct request *rq, int uptodate, int nr_bytes)
+/*
+ * Internal function
+ */
+static int blk_end_io(struct request *rq, int uptodate, int nr_bytes,
+ int bidi_bytes, int (drv_callback)(struct request *))
{
struct request_queue *q = rq->q;
unsigned long flags = 0UL;
@@ -3817,8 +3810,17 @@ 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, bidi_bytes))
+ return 1;
}
+ /* Special feature for tricky drivers */
+ if (drv_callback && drv_callback(rq))
+ return 1;
+
add_disk_randomness(rq->rq_disk);
spin_lock_irqsave(q->queue_lock, flags);
@@ -3827,6 +3829,32 @@ int blk_end_request(struct request *rq,
return 0;
}
+
+int blk_end_bidi_request(struct request *rq, int uptodate, int nr_bytes,
+ int bidi_bytes)
+{
+ return blk_end_io(rq, uptodate, nr_bytes, bidi_bytes, NULL);
+}
+EXPORT_SYMBOL_GPL(blk_end_bidi_request);
+
+/**
+ * blk_end_request - Helper function for drivers to complete the request.
+ * @rq: the request being processed
+ * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
+ * @nr_bytes: number of bytes to complete
+ *
+ * Description:
+ * Ends I/O on a number of bytes attached to @rq.
+ * If @rq has leftover, sets it up for the next range of segments.
+ *
+ * Return:
+ * 0 - we are done with this request
+ * 1 - still buffers pending for this request
+ **/
+int blk_end_request(struct request *rq, int uptodate, int nr_bytes)
+{
+ return blk_end_io(rq, uptodate, nr_bytes, 0, NULL);
+}
EXPORT_SYMBOL_GPL(blk_end_request);
/**
@@ -3878,25 +3906,7 @@ EXPORT_SYMBOL_GPL(__blk_end_request);
int blk_end_request_callback(struct request *rq, int uptodate, int nr_bytes,
int (drv_callback)(struct request *))
{
- struct request_queue *q = rq->q;
- unsigned long flags = 0UL;
-
- if (blk_fs_request(rq) || blk_pc_request(rq)) {
- if (__end_that_request_first(rq, uptodate, nr_bytes))
- return 1;
- }
-
- /* Special feature for tricky drivers */
- if (drv_callback && drv_callback(rq))
- return 1;
-
- add_disk_randomness(rq->rq_disk);
-
- spin_lock_irqsave(q->queue_lock, flags);
- complete_request(rq, uptodate);
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- return 0;
+ return blk_end_io(rq, uptodate, nr_bytes, 0, drv_callback);
}
EXPORT_SYMBOL_GPL(blk_end_request_callback);
--
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