On Mon, Feb 7, 2022 at 3:06 PM <[email protected]> wrote:
>
> From: Alison Schofield <[email protected]>
>
> Users need access to the CXL GET_PARTITION_INFO mailbox command
> to inspect and confirm changes to the partition layout of a memory
> device.
>
> Add libcxl APIs to create a new GET_PARTITION_INFO mailbox command,
> the command output data structure (privately), and accessor APIs to
> return the different fields in the partition info output.
>
> Per the CXL 2.0 specification, devices report partition capacities
> as multiples of 256MB. Define and use a capacity multiplier to
> convert the raw data into bytes for user consumption. Use byte
> format as the norm for all capacity values produced or consumed
> using CXL Mailbox commands.
>
> Signed-off-by: Alison Schofield <[email protected]>
> ---
> Documentation/cxl/lib/libcxl.txt | 1 +
> cxl/lib/libcxl.c | 57 ++++++++++++++++++++++++++++++++
> cxl/lib/libcxl.sym | 5 +++
> cxl/lib/private.h | 10 ++++++
> cxl/libcxl.h | 5 +++
> util/size.h | 1 +
> 6 files changed, 79 insertions(+)
>
> diff --git a/Documentation/cxl/lib/libcxl.txt
> b/Documentation/cxl/lib/libcxl.txt
> index 4392b47..a6986ab 100644
> --- a/Documentation/cxl/lib/libcxl.txt
> +++ b/Documentation/cxl/lib/libcxl.txt
> @@ -131,6 +131,7 @@ int cxl_memdev_read_label(struct cxl_memdev *memdev, void
> *buf, size_t length,
> size_t offset);
> int cxl_memdev_write_label(struct cxl_memdev *memdev, void *buf, size_t
> length,
> size_t offset);
> +struct cxl_cmd *cxl_cmd_new_get_partition(struct cxl_memdev *memdev);
>
> ----
>
> diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
> index e0b443f..33cf06b 100644
> --- a/cxl/lib/libcxl.c
> +++ b/cxl/lib/libcxl.c
> @@ -1985,6 +1985,12 @@ static int cxl_cmd_validate_status(struct cxl_cmd
> *cmd, u32 id)
> return 0;
> }
>
> +static unsigned long long
> +capacity_to_bytes(unsigned long long size)
If this helper converts an encoded le64 to bytes then the function
signature should reflect that:
static uint64_t cxl_capacity_to_bytes(leint64_t size)
> +{
> + return le64_to_cpu(size) * CXL_CAPACITY_MULTIPLIER;
> +}
> +
> /* Helpers for health_info fields (no endian conversion) */
> #define cmd_get_field_u8(cmd, n, N, field) \
> do { \
> @@ -2371,6 +2377,57 @@ CXL_EXPORT ssize_t
> cxl_cmd_read_label_get_payload(struct cxl_cmd *cmd,
> return length;
> }
>
> +CXL_EXPORT struct cxl_cmd *cxl_cmd_new_get_partition(struct cxl_memdev
> *memdev)
> +{
> + return cxl_cmd_new_generic(memdev,
> + CXL_MEM_COMMAND_ID_GET_PARTITION_INFO);
> +}
> +
> +static struct cxl_cmd_get_partition *
> +cmd_to_get_partition(struct cxl_cmd *cmd)
> +{
This could also check for cmd == NULL just to be complete.
> + if (cxl_cmd_validate_status(cmd,
> CXL_MEM_COMMAND_ID_GET_PARTITION_INFO))
> + return NULL;
> +
> + return cmd->output_payload;
> +}
> +
> +CXL_EXPORT unsigned long long
> +cxl_cmd_partition_get_active_volatile_size(struct cxl_cmd *cmd)
> +{
> + struct cxl_cmd_get_partition *c;
> +
> + c = cmd_to_get_partition(cmd);
> + return c ? capacity_to_bytes(c->active_volatile) : ULLONG_MAX;
I'd prefer kernel coding style which wants:
if (!c)
return ULLONG_MAX;
return cxl_capacity_to_bytes(c->active_volatile);
Otherwise, looks good to me:
Reviewed-by: Dan Williams <[email protected]>
