Re: 2.6.8-rc1-mm1

From: Jens Axboe
Date: Thu Jul 22 2004 - 10:10:38 EST


On Tue, Jul 20 2004, J.A. Magallon wrote:
>
> On 2004.07.14, Andrew Morton wrote:
> >
> > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.8-rc1/2.6.8-rc1-mm1/
> >
>
> It oopses if you try to write on a CDRW without media loaded. Who would do
> such a stupid thing ? Me the impatient trying to write before the drive ends
> to load the disc...

It's fixed in later -mm, not sure if Andrew has merged the patch yet. I
have posted it here a week or two ago, here it is again.

--- /mnt/kscratch/linux-2.6.5/mm/highmem.c 2004-04-04 05:37:25.000000000 +0200
+++ linux-2.6.5-SUSE-20040713/mm/highmem.c 2004-07-15 10:28:12.142262512 +0200
@@ -309,12 +309,10 @@ static void bounce_end_io(struct bio *bi
{
struct bio *bio_orig = bio->bi_private;
struct bio_vec *bvec, *org_vec;
- int i;
+ int i, err = 0;

if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
- goto out_eio;
-
- set_bit(BIO_UPTODATE, &bio_orig->bi_flags);
+ err = -EIO;

/*
* free up bounce indirect pages used
@@ -327,8 +325,7 @@ static void bounce_end_io(struct bio *bi
mempool_free(bvec->bv_page, pool);
}

-out_eio:
- bio_endio(bio_orig, bio_orig->bi_size, 0);
+ bio_endio(bio_orig, bio_orig->bi_size, err);
bio_put(bio);
}

--- /mnt/kscratch/linux-2.6.5/fs/bio.c 2004-07-14 23:12:42.000000000 +0200
+++ linux-2.6.5-SUSE-20040713/fs/bio.c 2004-07-15 10:30:53.263775247 +0200
@@ -549,7 +549,6 @@ static struct bio *__bio_map_user(reques
bio->bi_rw |= (1 << BIO_RW);

bio->bi_flags |= (1 << BIO_USER_MAPPED);
- blk_queue_bounce(q, &bio);
return bio;
out:
kfree(pages);
--- /mnt/kscratch/linux-2.6.5/drivers/block/scsi_ioctl.c 2004-07-14 23:12:42.000000000 +0200
+++ linux-2.6.5-SUSE-20040713/drivers/block/scsi_ioctl.c 2004-07-15 10:26:39.089364958 +0200
@@ -167,6 +167,13 @@ static int sg_io(request_queue_t *q, str
rq->flags |= REQ_BLOCK_PC;
bio = rq->bio;

+ /*
+ * bounce this after holding a reference to the original bio, it's
+ * needed for proper unmapping
+ */
+ if (rq->bio)
+ blk_queue_bounce(q, &rq->bio);
+
rq->timeout = (hdr->timeout * HZ) / 1000;
if (!rq->timeout)
rq->timeout = q->sg_timeout;
--- /mnt/kscratch/linux-2.6.5/drivers/cdrom/cdrom.c 2004-07-14 23:12:42.000000000 +0200
+++ linux-2.6.5-SUSE-20040713/drivers/cdrom/cdrom.c 2004-07-15 10:27:17.219225057 +0200
@@ -1975,6 +1975,9 @@ static int cdrom_read_cdda_bpc(struct cd
rq->timeout = 60 * HZ;
bio = rq->bio;

+ if (rq->bio)
+ blk_queue_bounce(q, &rq->bio);
+
if (blk_execute_rq(q, cdi->disk, rq)) {
struct request_sense *s = rq->sense;
ret = -EIO;
--- /mnt/kscratch/linux-2.6.5/drivers/block/ll_rw_blk.c 2004-07-14 23:12:42.000000000 +0200
+++ linux-2.6.5-SUSE-20040713/drivers/block/ll_rw_blk.c 2004-07-15 10:34:51.152967583 +0200
@@ -1807,6 +1807,12 @@ EXPORT_SYMBOL(blk_insert_request);
*
* A matching blk_rq_unmap_user() must be issued at the end of io, while
* still in process context.
+ *
+ * Note: The mapped bio may need to be bounced through blk_queue_bounce()
+ * before being submitted to the device, as pages mapped may be out of
+ * reach. It's the callers responsibility to make sure this happens. The
+ * original bio must be passed back in to blk_rq_unmap_user() for proper
+ * unmapping.
*/
struct request *blk_rq_map_user(request_queue_t *q, int rw, void __user *ubuf,
unsigned int len)


--
Jens Axboe

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