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SubjectRe: [PATCH V14 01/10] acpi: apei: read ack upon ghes record consumption
On Tue, Mar 28, 2017 at 01:30:31PM -0600, Tyler Baicar wrote:
> A RAS (Reliability, Availability, Serviceability) controller
> may be a separate processor running in parallel with OS
> execution, and may generate error records for consumption by
> the OS. If the RAS controller produces multiple error records,
> then they may be overwritten before the OS has consumed them.
>
> The Generic Hardware Error Source (GHES) v2 structure
> introduces the capability for the OS to acknowledge the
> consumption of the error record generated by the RAS
> controller. A RAS controller supporting GHESv2 shall wait for
> the acknowledgment before writing a new error record, thus
> eliminating the race condition.
>
> Add support for parsing of GHESv2 sub-tables as well.
>
> Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
> CC: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
> Reviewed-by: James Morse <james.morse@arm.com>
> ---
> drivers/acpi/apei/ghes.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---
> drivers/acpi/apei/hest.c | 7 +++++--
> include/acpi/ghes.h | 5 ++++-
> 3 files changed, 55 insertions(+), 6 deletions(-)

...

> @@ -249,10 +254,18 @@ static struct ghes *ghes_new(struct acpi_hest_generic *generic)
> ghes = kzalloc(sizeof(*ghes), GFP_KERNEL);
> if (!ghes)
> return ERR_PTR(-ENOMEM);
> +
> ghes->generic = generic;
> + if (IS_HEST_TYPE_GENERIC_V2(ghes)) {
> + rc = apei_map_generic_address(
> + &ghes->generic_v2->read_ack_register);

Yeah, that linebreak just to keep the 80-cols rule makes the code ugly
and hard to read.

Please put that mapping and unmapping in wrappers called
map_gen_v2(ghes) and unmap_gen_v2(ghes) or so, so that you can call them
wherever needed. Thus should make the flow a bit more understandable
what's going on and you won't have to repeat the unmapping lines in
ghes_fini().

> @@ -649,6 +669,23 @@ static void ghes_estatus_cache_add(
> rcu_read_unlock();
> }
>
> +static int ghes_ack_error(struct acpi_hest_generic_v2 *generic_v2)
> +{
> + int rc;
> + u64 val = 0;
> +
> + rc = apei_read(&val, &generic_v2->read_ack_register);
> + if (rc)
> + return rc;
> + val &= generic_v2->read_ack_preserve <<
> + generic_v2->read_ack_register.bit_offset;
> + val |= generic_v2->read_ack_write <<
> + generic_v2->read_ack_register.bit_offset;

Yeah, let them stick out, it more readable this way. Line spacing is
helpful too:

...
rc = apei_read(&val, &generic_v2->read_ack_register);
if (rc)
return rc;

val &= generic_v2->read_ack_preserve << generic_v2->read_ack_register.bit_offset;
val |= generic_v2->read_ack_write << generic_v2->read_ack_register.bit_offset;

return apei_write(val, &generic_v2->read_ack_register);
}

> + rc = apei_write(val, &generic_v2->read_ack_register);
> +
> + return rc;
> +}
> +
> static int ghes_proc(struct ghes *ghes)
> {
> int rc;
--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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