James Bottomley wrote:
> On Tue, 2009-02-10 at 17:43 +0000, James Bottomley wrote:
>> There's a current barrier to this: osd_initiator has also become a
>> consumer of blk_rq_append_bio().
>>
>> It seems to be emulating block internals, so I think the fix is twofold:
>>
>> 1. adjust blk_rq_map_kern to call blk_rq_append_bio() instead of
>> blk_rq_prep_bio() (with an extra failure path).
>> 2. make osd_initiator simply call it for additions.
>>
>> I can code up a patch to see if it works.
>
> So this is the patch to allow blk_rq_map_kern to append to requests,
> which is what I think is needed.
>
> Unfortunately unwinding osd_initator's bio dependence and putting it
> back on data buffers looks to be a bit of a longer chore.
>
> James
>
> ---
>
> diff --git a/block/blk-map.c b/block/blk-map.c
> index 25d15ff..1a1e26d 100644
> --- a/block/blk-map.c
> +++ b/block/blk-map.c
> @@ -289,6 +289,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
> int reading = rq_data_dir(rq) == READ;
> int do_copy = 0;
> struct bio *bio;
> + int ret;
>
> if (len > (q->max_hw_sectors << 9))
> return -EINVAL;
> @@ -310,7 +311,13 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
> if (do_copy)
> rq->cmd_flags |= REQ_COPY_USER;
>
> - blk_rq_bio_prep(q, rq, bio);
> + ret = blk_rq_append_bio(q, rq, bio);
> + if (unlikely(ret)) {
> + /* request is too big */
> + bio_put(bio);
> + return ret;
> + }
> +
> blk_queue_bounce(q, &rq->bio);
> rq->buffer = rq->data = NULL;
> return 0;
>
>
This works, with your patch and below code
I'm passing my tests. I would say it is pretty safe too,
since blk_rq_bio_prep would leak the bio if it was called
twice on same request, before.
Thanks, I'll send a proper patch after some more testing.
---
git diff --stat -p
drivers/scsi/osd/osd_initiator.c | 12 +++---------
1 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 1696130..9cfdce4 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -824,18 +824,12 @@ EXPORT_SYMBOL(osd_req_add_set_attr_list);
static int _append_map_kern(struct request *req,
void *buff, unsigned len, gfp_t flags)
{
- struct bio *bio;
int ret;
- bio = bio_map_kern(req->q, buff, len, flags);
- if (IS_ERR(bio)) {
- OSD_ERR("Failed bio_map_kern(%p, %d) => %ld\n", buff, len,
- PTR_ERR(bio));
- return PTR_ERR(bio);
- }
- ret = blk_rq_append_bio(req->q, req, bio);
+ ret = blk_rq_map_kern(req->q, req, buff, len, flags);
if (ret) {
- OSD_ERR("Failed blk_rq_append_bio(%p) => %d\n", bio, ret);
+ OSD_DEBUG("Failed blk_rq_map_kern(%p, %u) => %d\n",
+ buff, len, ret);
bio_put(bio);
}
return ret;
--
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