Re: [RESEND PATCH] block: cmdline-parser: add support for hidden disk space

[Shawn Lin]

On 2015/9/28 18:48, Caizhiyong wrote:
> Dear Shawn Lin:
>
>       The cmdline-parser is support skip some reserve disk space, or hidden some disk space.
>
>       See Documentation/block/cmdline-partition.txt

Wow, that's just what I need. Thanks.

> blkdevparts=<blkdev-def>[;<blkdev-def>]
>    <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
>      <partdef> := <size>[@<offset>](part-name)
>
>      The "offset" is next partition start address, If your bootargs is 'blkdevparts=mmcblk0:1G(data0),1G@2G(data1),-;', you will reserve 1G between mmcblk0p1 and mmcblk0p2;
>
> Looking forward to your feedback.
> Best regards.
> Cai Zhiyong.
> http://www.huawei.com
>
> > -----Original Message-----
> > From: Shawn Lin [mailto:shawn.lin@xxxxxxxxxxxxxx]
> > Sent: Monday, September 28, 2015 5:51 PM
> > To: Jens Axboe
> > Cc: Caizhiyong; linux-kernel@xxxxxxxxxxxxxxx; Shawn Lin
> > Subject: [RESEND PATCH] block: cmdline-parser: add support for hidden disk
> > space
> >
> > cmdline-partition now only support continuous disk space taken from
> > cmdline. When we need to reserve a disk space, for instance, 100m between
> > mmcblk0p1 and mmcblk0p2 for special use and wouldn't let kernel space
> > realize this "disk hole", we add this patch to ship adding this kind of
> > "disk hole" into the partition table. For any such cases, simply append
> > "hidden" to the end of subpart which is need to be reserved.
> >
> > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> >
> > ---
> >
> >   block/cmdline-parser.c         | 12 +++++++++++-
> >   include/linux/cmdline-parser.h |  1 +
> >   2 files changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/block/cmdline-parser.c b/block/cmdline-parser.c
> > index 9dbc67e..fcca57d 100644
> > --- a/block/cmdline-parser.c
> > +++ b/block/cmdline-parser.c
> > @@ -68,6 +68,11 @@ static int parse_subpart(struct cmdline_subpart
> > **subpart, char *partdef)
> >   		partdef += 2;
> >   	}
> >
> > +	if (!strncmp(partdef, "hidden", 6)) {
> > +		new_subpart->flags |= PF_HIDDEN;
> > +		partdef += 6;
> > +	}
> > +
> >   	*subpart = new_subpart;
> >   	return 0;
> >   fail:
> > @@ -128,7 +133,9 @@ static int parse_parts(struct cmdline_parts **parts,
> > const char *bdevdef)
> >   		if (ret)
> >   			goto fail;
> >
> > -		newparts->nr_subparts++;
> > +		if (!((*next_subpart)->flags & PF_HIDDEN))
> > +			newparts->nr_subparts++;
> > +
> >   		next_subpart = &(*next_subpart)->next_subpart;
> >   	}
> >
> > @@ -245,6 +252,9 @@ int cmdline_parts_set(struct cmdline_parts *parts,
> > sector_t disk_size,
> >
> >   		from += subpart->size;
> >
> > +		if (subpart->flags & PF_HIDDEN)
> > +			continue;
> > +
> >   		if (add_part(slot, subpart, param))
> >   			break;
> >   	}
> > diff --git a/include/linux/cmdline-parser.h b/include/linux/cmdline-parser.h
> > index 2e6dce6..7c1cb3c 100644
> > --- a/include/linux/cmdline-parser.h
> > +++ b/include/linux/cmdline-parser.h
> > @@ -14,6 +14,7 @@
> >   /* partition flags */
> >   #define PF_RDONLY                   0x01 /* Device is read only */
> >   #define PF_POWERUP_LOCK             0x02 /* Always locked after reset
> > */
> > +#define PF_HIDDEN                   0x04 /* Hidden from partition
> > table */
> >
> >   struct cmdline_subpart {
> >   	char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */
> > --
> > 2.3.7


--
Best Regards
Shawn Lin

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