Re: [PATCH 12/18] common: partitions: record whether disk is GPT or MBR partitioned

[Marco Felsch <m.felsch@pengutronix.de>]

On 23-05-31, Ahmad Fatoum wrote:
> Currently, the only way to differentiate between a GPT disk and a MBR
> one is to check whether the cdev's device has a guid (=> GPT) or a
> nt_signature (=> MBR) device parameter. We already have a flag parameter
> though, so let's record this info there for easy retrieval.
> 
> We intentionally don't use the struct cdev::filetype member, because
> we don't want to change behavior of file_detect_type().
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  common/partitions/dos.c |  2 ++
>  common/partitions/efi.c |  2 ++
>  fs/fs.c                 |  4 ++++
>  include/driver.h        | 20 +++++++++++++++++---
>  4 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/common/partitions/dos.c b/common/partitions/dos.c
> index ad60c0b27b46..7472824b00b9 100644
> --- a/common/partitions/dos.c
> +++ b/common/partitions/dos.c
> @@ -185,6 +185,8 @@ static void dos_partition(void *buf, struct block_device *blk,
>  	if (signature)
>  		sprintf(blk->cdev.diskuuid, "%08x", signature);
>  
> +	blk->cdev.flags |= DEVFS_IS_MBR_PARTITIONED;
> +
>  	table = (struct partition_entry *)&buffer[446];
>  
>  	for (i = 0; i < 4; i++) {
> diff --git a/common/partitions/efi.c b/common/partitions/efi.c
> index 780a8695e8a8..df63b82afe24 100644
> --- a/common/partitions/efi.c
> +++ b/common/partitions/efi.c
> @@ -449,6 +449,8 @@ static void efi_partition(void *buf, struct block_device *blk,
>  	snprintf(blk->cdev.diskuuid, sizeof(blk->cdev.diskuuid), "%pUl", &gpt->disk_guid);
>  	dev_add_param_string_fixed(blk->dev, "guid", blk->cdev.diskuuid);
>  
> +	blk->cdev.flags |= DEVFS_IS_GPT_PARTITIONED;
> +
>  	nb_part = le32_to_cpu(gpt->num_partition_entries);
>  
>  	if (nb_part > MAX_PARTITION) {
> diff --git a/fs/fs.c b/fs/fs.c
> index 9d8aab268ca4..2d2d327c5fbc 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -94,6 +94,10 @@ void cdev_print(const struct cdev *cdev)
>  			printf(" table-partition");
>  		if (cdev->flags & DEVFS_IS_MCI_MAIN_PART_DEV)
>  			printf(" mci-main-partition");
> +		if (cdev->flags & DEVFS_IS_GPT_PARTITIONED)
> +			printf(" gpt-partitioned");
> +		if (cdev->flags & DEVFS_IS_MBR_PARTITIONED)
> +			printf(" mbr-partitioned");
>  		if (cdev->mtd)
>  			printf(" mtd");
>  		printf(" )");
> diff --git a/include/driver.h b/include/driver.h
> index 118d2adb6750..5f2eae65466f 100644
> --- a/include/driver.h
> +++ b/include/driver.h
> @@ -584,9 +584,23 @@ extern struct list_head cdev_list;
>  #define DEVFS_PARTITION_FIXED		(1U << 0)
>  #define DEVFS_PARTITION_READONLY	(1U << 1)
>  #define DEVFS_IS_CHARACTER_DEV		(1U << 3)
> -#define DEVFS_IS_MCI_MAIN_PART_DEV	(1U << 4)
> -#define DEVFS_PARTITION_FROM_OF		(1U << 5)
> -#define DEVFS_PARTITION_FROM_TABLE	(1U << 6)
> +#define DEVFS_PARTITION_FROM_OF		(1U << 4)
> +#define DEVFS_PARTITION_FROM_TABLE	(1U << 5)
> +#define DEVFS_IS_GPT_PARTITIONED	(1U << 6)
> +#define DEVFS_IS_MBR_PARTITIONED	(1U << 7)
> +#define DEVFS_IS_MCI_MAIN_PART_DEV	(1U << 8)

Why do you reorder the bits here again?

> +
> +static inline bool cdev_is_gpt_partitioned(const struct cdev *master)
> +{
> +	return master && (master->flags & DEVFS_IS_GPT_PARTITIONED)
> +		== DEVFS_IS_GPT_PARTITIONED;

Why not just: 'return !!(master->flags & DEVFS_IS_GPT_PARTITIONED)' ?

Regards,
  Marco

> +}
> +
> +static inline bool cdev_is_mbr_partitioned(const struct cdev *master)
> +{
> +	return master && (master->flags & DEVFS_IS_MBR_PARTITIONED)
> +		== DEVFS_IS_MBR_PARTITIONED;
> +}
>  
>  struct cdev *devfs_add_partition(const char *devname, loff_t offset,
>  		loff_t size, unsigned int flags, const char *name);
> -- 
> 2.39.2
> 
> 
>