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

Heinrich Schuchardt
2021-10-08T08:24:09Z

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 */
>>>>