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From: Tobias Waldekranz <tobias@waldekranz.com>
To: Bin Meng <bmeng@tinylab.org>, Simon Glass <sjg@chromium.org>,
	U-Boot Mailing List <u-boot@lists.denx.de>
Subject: Re: [PATCH 09/15] blk: blkmap: Support mapping to device of any block size
Date: Tue, 26 Sep 2023 21:29:10 +0200	[thread overview]
Message-ID: <875y3wohrt.fsf@waldekranz.com> (raw)
In-Reply-To: <20230926084346.2237483-10-bmeng@tinylab.org>

On tis, sep 26, 2023 at 16:43, Bin Meng <bmeng@tinylab.org> wrote:
> At present if a device to map has a block size other than 512,
> the blkmap map process just fails. There is no reason why we
> can't just use the block size of the mapped device.

Won't this be very confusing to the user?

The blkmap device uses a fixed block size of 512:

https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/block/blkmap.c?ref_type=heads#L393

So if I map a slice of a 4k device into a blkmap, then

    blkmap read 0x80000000 0 1

would copy 4k instead of 512 bytes from the lower device to 0x80000000,
even though the blkmap reports a block size of 512.

It seems to me that the expected behavior would be that only the first
512 bytes would be copied in the command above.

>
> Signed-off-by: Bin Meng <bmeng@tinylab.org>
> ---
>
>  drivers/block/blkmap.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/block/blkmap.c b/drivers/block/blkmap.c
> index f6acfa8927..149a4cac3e 100644
> --- a/drivers/block/blkmap.c
> +++ b/drivers/block/blkmap.c
> @@ -171,11 +171,11 @@ int blkmap_map_linear(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
>  
>  	bd = dev_get_uclass_plat(bm->blk);
>  	lbd = dev_get_uclass_plat(lblk);
> -	if (lbd->blksz != bd->blksz)
> -		/* We could support block size translation, but we
> -		 * don't yet.
> -		 */

Hence this comment ^

> -		return -EINVAL;
> +	if (lbd->blksz != bd->blksz) {
> +		/* update to match the mapped device */
> +		bd->blksz = lbd->blksz;
> +		bd->log2blksz = LOG2(bd->blksz);
> +	}
>  
>  	linear = malloc(sizeof(*linear));
>  	if (!linear)
> -- 
> 2.25.1

  reply	other threads:[~2023-09-26 19:29 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-26  8:43 [PATCH 00/15] blk: sandbox: Support binding a device with a given logical block size Bin Meng
2023-09-26  8:43 ` [PATCH 01/15] blk: Use a macro for the typical " Bin Meng
2023-10-02  1:16   ` Simon Glass
2023-09-26  8:43 ` [PATCH 02/15] cmd: host: Mandate the filename parameter in the 'bind' command Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 03/15] blk: sandbox: Support binding a device with a given logical block size Bin Meng
2023-09-26  8:43 ` [PATCH 04/15] blk: host_dev: Make host_sb_detach_file() and host_sb_ops static Bin Meng
2023-10-02  1:16   ` Simon Glass
2023-09-26  8:43 ` [PATCH 05/15] blk: host_dev: Sanity check on the size of host backing file Bin Meng
2023-10-02  1:16   ` Simon Glass
2023-09-26  8:43 ` [PATCH 06/15] cmd: host: Print out the block size of the host device Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 07/15] blk: blkmap: Make bind/unbind routines static Bin Meng
2023-10-02  1:16   ` Simon Glass
2023-09-26  8:43 ` [PATCH 08/15] cmd: blkmap: Make map_handlers[] and its .fn static Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 09/15] blk: blkmap: Support mapping to device of any block size Bin Meng
2023-09-26 19:29   ` Tobias Waldekranz [this message]
2023-09-26 22:44     ` Bin Meng
2023-10-02  1:16   ` Simon Glass
2023-09-26  8:43 ` [PATCH 10/15] cmd: blk_common: Use macros for the return values Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-10-10  9:05     ` Bin Meng
2023-10-10 14:58       ` Simon Glass
2023-10-10 20:17         ` Tom Rini
2023-09-26  8:43 ` [PATCH 11/15] dm: blk: Rename get_desc() and make it externally visible Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 12/15] cmd: blk_common: Stop using hard-coded block size for Sandbox operations Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 13/15] dm: blk: Drop blk_{read,write}_devnum() Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 14/15] disk: part: Print out the unknown device uclass id Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:43 ` [PATCH 15/15] disk: part: Handle blkmap device in print_part_header() Bin Meng
2023-10-02  1:17   ` Simon Glass
2023-09-26  8:58 ` [PATCH 00/15] blk: sandbox: Support binding a device with a given logical block size Heinrich Schuchardt
2023-09-26 14:11   ` Bin Meng
2023-10-11  1:49 ` Tom Rini

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