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Message-Id: <20070911.150545.125541111.k-ueda@ct.jp.nec.com>
Date: Tue, 11 Sep 2007 15:05:45 -0400 (EDT)
From: Kiyoshi Ueda <k-ueda@...jp.nec.com>
To: jens.axboe@...cle.com, linux-kernel@...r.kernel.org,
linux-scsi@...r.kernel.org, linux-ide@...r.kernel.org,
mike.miller@...com, grant.likely@...retlab.ca
Cc: dm-devel@...hat.com, j-nomura@...jp.nec.com, k-ueda@...jp.nec.com
Subject: [PATCH 26/27] blk_end_request: changing ide-cd (take 2)
This patch converts ide-cd (cdrom_newpc_intr()) to use blk_end_request().
Due to the oddness of the driver, the patch adds a variant of
the interface, blk_end_request_callback().
cdrom_newpc_intr() of ide-cd is the only function in the kernel tree
which needs to call end_that_request_first() and
end_that_request_last() separately.
blk_end_request_callback() allows it to pass callback function to do
something between end_that_request_first() and end_that_request_last().
ide-cd (cdrom_newpc_intr) needs to the followings:
1. call post_transform_command() to modify request contents
2. wait completing request until DRQ_STAT is cleared
after end_that_request_first() and before end_that_request_last().
As for the second one, ide-cd will wait for the interrupt from device.
So blk_end_request() has to return without completing request even if
no leftover in the request.
Signed-off-by: Kiyoshi Ueda <k-ueda@...jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@...jp.nec.com>
---
block/ll_rw_blk.c | 54 +++++++++++++++++++++++++++++++++
drivers/ide/ide-cd.c | 78 ++++++++++++++++++++++++++++++++++++++----------
include/linux/blkdev.h | 3 +
3 files changed, 118 insertions(+), 17 deletions(-)
diff -rupN 25-ide-normal-caller-change/block/ll_rw_blk.c 26-ide-odd-caller-change/block/ll_rw_blk.c
--- 25-ide-normal-caller-change/block/ll_rw_blk.c 2007-09-10 17:57:59.000000000 -0400
+++ 26-ide-odd-caller-change/block/ll_rw_blk.c 2007-09-10 18:21:27.000000000 -0400
@@ -3845,6 +3845,60 @@ int __blk_end_request(struct request *rq
}
EXPORT_SYMBOL_GPL(__blk_end_request);
+/**
+ * blk_end_request_callback - Special helper function for the ide-cd driver
+ * @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
+ * @drv_callback: function called between completion of bios in the request
+ * and completion of the request.
+ * If the callback returns non 0, this helper returns without
+ * completion of the request.
+ *
+ * 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.
+ *
+ * This special helper function for the ide-cd driver is used
+ * to complete the request only in cdrom_newpc_intr().
+ * This interface will be removed when cdrom_newpc_intr() is rewritten.
+ * Don't use this interface in other places.
+ *
+ * Return:
+ * 0 - we are done with this request
+ * 1 - this request is not freed yet.
+ * this request still has pending buffers or
+ * the ide-cd driver doesn't want to finish this request yet.
+ **/
+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 drivers/ide/ide-cd.c:cdrom_newpc_intr() */
+ if (drv_callback && drv_callback(rq))
+ return 1;
+
+ /*
+ * No need to check the argument here because it is done
+ * in add_disk_randomness().
+ */
+ 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;
+}
+EXPORT_SYMBOL_GPL(blk_end_request_callback);
+
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio)
{
diff -rupN 25-ide-normal-caller-change/drivers/ide/ide-cd.c 26-ide-odd-caller-change/drivers/ide/ide-cd.c
--- 25-ide-normal-caller-change/drivers/ide/ide-cd.c 2007-09-10 18:17:38.000000000 -0400
+++ 26-ide-odd-caller-change/drivers/ide/ide-cd.c 2007-09-10 18:21:27.000000000 -0400
@@ -1675,6 +1675,37 @@ static void post_transform_command(struc
}
}
+/*
+ * Called from blk_end_request_callback() after the data of the request
+ * is completed and before the request is completed.
+ */
+static int cdrom_newpc_intr_dma_cb(struct request *rq)
+{
+ ide_drive_t *drive = rq->q->queuedata;
+ spinlock_t *ide_lock = rq->q->queue_lock;
+ unsigned long flags = 0UL;
+
+ rq->data_len = 0;
+ post_transform_command(rq);
+
+ spin_lock_irqsave(ide_lock, flags);
+ HWGROUP(drive)->rq = NULL;
+ spin_unlock_irqrestore(ide_lock, flags);
+
+ return 0;
+}
+
+/*
+ * Called from blk_end_request_callback() after the data of the request
+ * is completed and before the request is completed.
+ * By returning value '1', blk_end_request_callback() returns immediately
+ * without completing the request.
+ */
+static int cdrom_newpc_intr_dummy_cb(struct request *rq)
+{
+ return 1;
+}
+
typedef void (xfer_func_t)(ide_drive_t *, void *, u32);
/*
@@ -1713,9 +1744,16 @@ static ide_startstop_t cdrom_newpc_intr(
return ide_error(drive, "dma error", stat);
}
- end_that_request_chunk(rq, 1, rq->data_len);
- rq->data_len = 0;
- goto end_request;
+ /*
+ * post_transform_command() needs to be called after
+ * the data of the request is completed, since it may
+ * modify the data area of the request.
+ * So use the callback special feature of blk_end_request().
+ */
+ if (blk_end_request_callback(rq, 1, rq->data_len,
+ cdrom_newpc_intr_dma_cb))
+ BUG();
+ return ide_stopped;
}
/*
@@ -1733,8 +1771,18 @@ static ide_startstop_t cdrom_newpc_intr(
/*
* If DRQ is clear, the command has completed.
*/
- if ((stat & DRQ_STAT) == 0)
- goto end_request;
+ if ((stat & DRQ_STAT) == 0) {
+ if (!rq->data_len)
+ post_transform_command(rq);
+
+ spin_lock_irqsave(&ide_lock, flags);
+ if (__blk_end_request(rq, 1, 0))
+ BUG();
+ HWGROUP(drive)->rq = NULL;
+ spin_unlock_irqrestore(&ide_lock, flags);
+
+ return ide_stopped;
+ }
/*
* check which way to transfer data
@@ -1787,7 +1835,14 @@ static ide_startstop_t cdrom_newpc_intr(
rq->data_len -= blen;
if (rq->bio)
- end_that_request_chunk(rq, 1, blen);
+ /*
+ * The request can't be completed until DRQ is cleared.
+ * So complete the data, but don't complete the request
+ * using the dummy function for the callback feature
+ * of blk_end_request().
+ */
+ blk_end_request_callback(rq, 1, blen,
+ cdrom_newpc_intr_dummy_cb);
else
rq->data += blen;
}
@@ -1808,17 +1863,6 @@ static ide_startstop_t cdrom_newpc_intr(
ide_set_handler(drive, cdrom_newpc_intr, rq->timeout, NULL);
return ide_started;
-
-end_request:
- if (!rq->data_len)
- post_transform_command(rq);
-
- spin_lock_irqsave(&ide_lock, flags);
- blkdev_dequeue_request(rq);
- end_that_request_last(rq, 1);
- HWGROUP(drive)->rq = NULL;
- spin_unlock_irqrestore(&ide_lock, flags);
- return ide_stopped;
}
static ide_startstop_t cdrom_write_intr(ide_drive_t *drive)
diff -rupN 25-ide-normal-caller-change/include/linux/blkdev.h 26-ide-odd-caller-change/include/linux/blkdev.h
--- 25-ide-normal-caller-change/include/linux/blkdev.h 2007-09-10 17:44:43.000000000 -0400
+++ 26-ide-odd-caller-change/include/linux/blkdev.h 2007-09-10 18:21:27.000000000 -0400
@@ -734,6 +734,9 @@ extern int end_that_request_chunk(struct
extern void end_that_request_last(struct request *, int);
extern void end_request(struct request *, int);
extern void end_queued_request(struct request *, int);
+extern int blk_end_request_callback(struct request *rq, int uptodate,
+ int nr_bytes,
+ int (drv_callback)(struct request *));
extern void blk_complete_request(struct request *);
/*
-
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