Re: [RFC 07/22] dm: blk: add UCLASS_PARTITION

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 10/8/21 02:51, AKASHI Takahiro wrote:
> On Mon, Oct 04, 2021 at 12:27:59PM +0900, AKASHI Takahiro wrote:
>> On Fri, Oct 01, 2021 at 11:30:37AM +0200, Heinrich Schuchardt wrote:
>>>
>>>
>>> On 10/1/21 07:01, AKASHI Takahiro wrote:
>>>> UCLASS_PARTITION device will be created as a child node of
>>>> UCLASS_BLK device.
>>>>
>>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
>>>> ---
>>>>    drivers/block/blk-uclass.c | 111 +++++++++++++++++++++++++++++++++++++
>>>>    include/blk.h              |   9 +++
>>>>    include/dm/uclass-id.h     |   1 +
>>>>    3 files changed, 121 insertions(+)
>>>>
>>>> diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
>>>> index 83682dcc181a..dd7f3c0fe31e 100644
>>>> --- a/drivers/block/blk-uclass.c
>>>> +++ b/drivers/block/blk-uclass.c
>>>> @@ -12,6 +12,7 @@
>>>>    #include <log.h>
>>>>    #include <malloc.h>
>>>>    #include <part.h>
>>>> +#include <string.h>
>>>>    #include <dm/device-internal.h>
>>>>    #include <dm/lists.h>
>>>>    #include <dm/uclass-internal.h>
>>>> @@ -695,6 +696,44 @@ int blk_unbind_all(int if_type)
>>>>    	return 0;
>>>>    }
>>>>
>>>> +int blk_create_partitions(struct udevice *parent)
>>>> +{
>>>> +	int part, count;
>>>> +	struct blk_desc *desc = dev_get_uclass_plat(parent);
>>>> +	struct disk_partition info;
>>>> +	struct disk_part *part_data;
>>>> +	char devname[32];
>>>> +	struct udevice *dev;
>>>> +	int ret;
>>>> +
>>>> +	if (!CONFIG_IS_ENABLED(PARTITIONS) ||
>>>> +	    !CONFIG_IS_ENABLED(HAVE_BLOCK_DEVICE))
>>>> +		return 0;
>>>> +
>>>> +	/* Add devices for each partition */
>>>> +	for (count = 0, part = 1; part <= MAX_SEARCH_PARTITIONS; part++) {
>>>> +		if (part_get_info(desc, part, &info))
>>>> +			continue;
>>>> +		snprintf(devname, sizeof(devname), "%s:%d", parent->name,
>>>> +			 part);
>>>> +
>>>> +		ret = device_bind_driver(parent, "blk_partition",
>>>> +					 strdup(devname), &dev);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +
>>>> +		part_data = dev_get_uclass_plat(dev);
>>>> +		part_data->partnum = part;
>>>> +		part_data->gpt_part_info = info;
>>>> +		count++;
>>>> +
>>>> +		device_probe(dev);
>>>> +	}
>>>> +	debug("%s: %d partitions found in %s\n", __func__, count, parent->name);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>>    static int blk_post_probe(struct udevice *dev)
>>>>    {
>>>>    	if (IS_ENABLED(CONFIG_PARTITIONS) &&
>>>> @@ -713,3 +752,75 @@ UCLASS_DRIVER(blk) = {
>>>>    	.post_probe	= blk_post_probe,
>>>>    	.per_device_plat_auto	= sizeof(struct blk_desc),
>>>>    };
>>>> +
>>>> +static ulong blk_part_read(struct udevice *dev, lbaint_t start,
>>>> +			   lbaint_t blkcnt, void *buffer)
>>>> +{
>>>> +	struct udevice *parent;
>>>> +	struct disk_part *part;
>>>> +	const struct blk_ops *ops;
>>>> +
>>>> +	parent = dev_get_parent(dev);
>>>
>>> What device type will the parent have if it is a eMMC hardware partition?
>>>
>>>> +	ops = blk_get_ops(parent);
>>>> +	if (!ops->read)
>>>> +		return -ENOSYS;
>>>> +
>>>> +	part = dev_get_uclass_plat(dev);
>>>
>>> You should check that we do not access the block device past the
>>> partition end:
>>
>> Yes, I will fix all of checks.
>>
>>> struct blk_desc *desc = dev_get_uclass_plat(parent);
>>> if ((start + blkcnt) * desc->blksz < part->gpt_part_info.blksz)
>>> 	return -EFAULT.
>>>
>>>> +	start += part->gpt_part_info.start;
>
> A better solution is:
>          if (start >= part->gpt_part_info.size)
>                  return 0;
>
>          if ((start + blkcnt) > part->gpt_part_info.size)
>                  blkcnt = part->gpt_part_info.size - start;
>          start += part->gpt_part_info.start;
> instead of returning -EFAULT.
> (note that start and blkcnt are in "block".)

What is your motivation to support an illegal access?

We will implement the EFI_BLOCK_IO_PROTOCOL based on this function. The
ReadBlocks() and WriteBlocks() services must return
EFI_INVALID_PARAMETER if the read request contains LBAs that are not
valid. So we should return an error code here that can be translated
into EFI_INVALID_PARAMETER.

Best regards

Heinrich

>
> -Takahiro Akashi
>
>>>> +
>>>> +	return ops->read(parent, start, blkcnt, buffer);
>>>> +}
>>>> +
>>>> +static ulong blk_part_write(struct udevice *dev, lbaint_t start,
>>>> +			    lbaint_t blkcnt, const void *buffer)
>>>> +{
>>>> +	struct udevice *parent;
>>>> +	struct disk_part *part;
>>>> +	const struct blk_ops *ops;
>>>> +
>>>> +	parent = dev_get_parent(dev);
>>>> +	ops = blk_get_ops(parent);
>>>> +	if (!ops->write)
>>>> +		return -ENOSYS;
>>>> +
>>>> +	part = dev_get_uclass_plat(dev);
>>>> +	start += part->gpt_part_info.start;
>>>
>>> here too
>>>
>>>> +
>>>> +	return ops->write(parent, start, blkcnt, buffer);
>>>> +}
>>>> +
>>>> +static ulong blk_part_erase(struct udevice *dev, lbaint_t start,
>>>> +			    lbaint_t blkcnt)
>>>> +{
>>>> +	struct udevice *parent;
>>>> +	struct disk_part *part;
>>>> +	const struct blk_ops *ops;
>>>> +
>>>> +	parent = dev_get_parent(dev);
>>>> +	ops = blk_get_ops(parent);
>>>> +	if (!ops->erase)
>>>> +		return -ENOSYS;
>>>> +
>>>> +	part = dev_get_uclass_plat(dev);
>>>> +	start += part->gpt_part_info.start;
>>>
>>> here too
>>>
>>> Best regards
>>>
>>> Heinrich
>>>
>>>> +
>>>> +	return ops->erase(parent, start, blkcnt);
>>>> +}
>>>> +
>>>> +static const struct blk_ops blk_part_ops = {
>>>> +	.read	= blk_part_read,
>>>> +	.write	= blk_part_write,
>>>> +	.erase	= blk_part_erase,
>>>> +};
>>>> +
>>>> +U_BOOT_DRIVER(blk_partition) = {
>>>> +	.name		= "blk_partition",
>>>> +	.id		= UCLASS_PARTITION,
>>>> +	.ops		= &blk_part_ops,
>>>> +};
>>>> +
>>>> +UCLASS_DRIVER(partition) = {
>>>> +	.id		= UCLASS_PARTITION,
>>>> +	.per_device_plat_auto	= sizeof(struct disk_part),
>>>> +	.name		= "partition",
>>>> +};
>>>> diff --git a/include/blk.h b/include/blk.h
>>>> index 19bab081c2cd..3d883eb1db64 100644
>>>> --- a/include/blk.h
>>>> +++ b/include/blk.h
>>>> @@ -366,6 +366,15 @@ int blk_create_devicef(struct udevice *parent, const char *drv_name,
>>>>    		       const char *name, int if_type, int devnum, int blksz,
>>>>    		       lbaint_t lba, struct udevice **devp);
>>>>
>>>> +/**
>>>> + * blk_create_partitions - Create block devices for disk partitions
>>>> + *
>>>> + * Create UCLASS_PARTITION udevices for each of disk partitions in @parent
>>>> + *
>>>> + * @parent:	Whole disk device
>>>> + */
>>>> +int blk_create_partitions(struct udevice *parent);
>>>> +
>>>>    /**
>>>>     * blk_unbind_all() - Unbind all device of the given interface type
>>>>     *
>>>> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
>>>> index e7edd409f307..30892d01ce13 100644
>>>> --- a/include/dm/uclass-id.h
>>>> +++ b/include/dm/uclass-id.h
>>>> @@ -80,6 +80,7 @@ enum uclass_id {
>>>>    	UCLASS_P2SB,		/* (x86) Primary-to-Sideband Bus */
>>>>    	UCLASS_PANEL,		/* Display panel, such as an LCD */
>>>>    	UCLASS_PANEL_BACKLIGHT,	/* Backlight controller for panel */
>>>> +	UCLASS_PARTITION,	/* Logical disk partition device */
>>>>    	UCLASS_PCH,		/* x86 platform controller hub */
>>>>    	UCLASS_PCI,		/* PCI bus */
>>>>    	UCLASS_PCI_EP,		/* PCI endpoint device */
>>>>