Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Fri, Dec 17, 2021 at 10:10 AM Rafael J. Wysocki wrote: > > On Mon, Dec 13, 2021 at 9:46 PM Andy Shevchenko > wrote: > > > > Strictly speaking the comparison between guid_t and raw buffer > > is not correct. Import GUID to variable of guid_t type and then > > compare. > > > > Signed-off-by: Andy Shevchenko > > Dan, are you going to take care of this or should I? I'll take it. Apologies for the delay in responding. I am still catching up on some patch merging backlog.
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Mon, Dec 13, 2021 at 9:46 PM Andy Shevchenko
wrote:
>
> Strictly speaking the comparison between guid_t and raw buffer
> is not correct. Import GUID to variable of guid_t type and then
> compare.
>
> Signed-off-by: Andy Shevchenko
Dan, are you going to take care of this or should I?
> ---
> drivers/acpi/nfit/core.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index 7dd80acf92c7..e5d7f2bda13f 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -678,10 +678,12 @@ static const char *spa_type_name(u16 type)
>
> int nfit_spa_type(struct acpi_nfit_system_address *spa)
> {
> + guid_t guid;
> int i;
>
> + import_guid(, spa->range_guid);
> for (i = 0; i < NFIT_UUID_MAX; i++)
> - if (guid_equal(to_nfit_uuid(i), (guid_t *)>range_guid))
> + if (guid_equal(to_nfit_uuid(i), ))
> return i;
> return -1;
> }
> --
> 2.33.0
>
[PATCH v1 1/1] ACPI: NFIT: Import GUID before use
Strictly speaking the comparison between guid_t and raw buffer
is not correct. Import GUID to variable of guid_t type and then
compare.
Signed-off-by: Andy Shevchenko
---
drivers/acpi/nfit/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 7dd80acf92c7..e5d7f2bda13f 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -678,10 +678,12 @@ static const char *spa_type_name(u16 type)
int nfit_spa_type(struct acpi_nfit_system_address *spa)
{
+ guid_t guid;
int i;
+ import_guid(, spa->range_guid);
for (i = 0; i < NFIT_UUID_MAX; i++)
- if (guid_equal(to_nfit_uuid(i), (guid_t *)>range_guid))
+ if (guid_equal(to_nfit_uuid(i), ))
return i;
return -1;
}
--
2.33.0
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Fri, Apr 16, 2021 at 10:34 AM Andy Shevchenko wrote: > > On Fri, Apr 16, 2021 at 09:15:34AM -0700, Dan Williams wrote: > > On Fri, Apr 16, 2021 at 1:58 AM Andy Shevchenko > > wrote: > > > On Fri, Apr 16, 2021 at 8:28 AM Dan Williams > > > wrote: > > > > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko > > > > wrote: > > > > > > > > > > Strictly speaking the comparison between guid_t and raw buffer > > > > > is not correct. Import GUID to variable of guid_t type and then > > > > > compare. > > > > > > > > Hmm, what about something like the following instead, because it adds > > > > safety. Any concerns about evaluating x twice in a macro should be > > > > alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is > > > > not an array. > > > > > > ARRAY_SIZE doesn't check type. > > > > See __must_be_array. > > > > > I don't like hiding ugly casts like this. > > > > See PTR_ERR, ERR_PTR, ERR_CAST. > > It's special, i.e. error pointer case. We don't handle such here. > > > There's nothing broken about the way the code currently stands, so I'd > > rather try to find something to move the implementation forward than > > sideways. > > Submit a patch then. I rest my case b/c I consider that ugly castings worse > than additional API call, although it's not ideal. It sounds like you'll NAK that patch, and I'm not too enthusiastic about these proposed changes either because I disagree that the code is incorrect. Is there another compromise?
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Fri, Apr 16, 2021 at 09:15:34AM -0700, Dan Williams wrote: > On Fri, Apr 16, 2021 at 1:58 AM Andy Shevchenko > wrote: > > On Fri, Apr 16, 2021 at 8:28 AM Dan Williams > > wrote: > > > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko > > > wrote: > > > > > > > > Strictly speaking the comparison between guid_t and raw buffer > > > > is not correct. Import GUID to variable of guid_t type and then > > > > compare. > > > > > > Hmm, what about something like the following instead, because it adds > > > safety. Any concerns about evaluating x twice in a macro should be > > > alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is > > > not an array. > > > > ARRAY_SIZE doesn't check type. > > See __must_be_array. > > > I don't like hiding ugly casts like this. > > See PTR_ERR, ERR_PTR, ERR_CAST. It's special, i.e. error pointer case. We don't handle such here. > There's nothing broken about the way the code currently stands, so I'd > rather try to find something to move the implementation forward than > sideways. Submit a patch then. I rest my case b/c I consider that ugly castings worse than additional API call, although it's not ideal. -- With Best Regards, Andy Shevchenko
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Fri, Apr 16, 2021 at 1:58 AM Andy Shevchenko wrote: > > On Fri, Apr 16, 2021 at 8:28 AM Dan Williams wrote: > > > > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko > > wrote: > > > > > > Strictly speaking the comparison between guid_t and raw buffer > > > is not correct. Import GUID to variable of guid_t type and then > > > compare. > > > > Hmm, what about something like the following instead, because it adds > > safety. Any concerns about evaluating x twice in a macro should be > > alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is > > not an array. > > ARRAY_SIZE doesn't check type. See __must_be_array. > I don't like hiding ugly casts like this. See PTR_ERR, ERR_PTR, ERR_CAST. There's nothing broken about the way the code currently stands, so I'd rather try to find something to move the implementation forward than sideways.
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Fri, Apr 16, 2021 at 8:28 AM Dan Williams wrote: > > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko > wrote: > > > > Strictly speaking the comparison between guid_t and raw buffer > > is not correct. Import GUID to variable of guid_t type and then > > compare. > > Hmm, what about something like the following instead, because it adds > safety. Any concerns about evaluating x twice in a macro should be > alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is > not an array. ARRAY_SIZE doesn't check type. I don't like hiding ugly casts like this. -- With Best Regards, Andy Shevchenko
Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko
wrote:
>
> Strictly speaking the comparison between guid_t and raw buffer
> is not correct. Import GUID to variable of guid_t type and then
> compare.
Hmm, what about something like the following instead, because it adds
safety. Any concerns about evaluating x twice in a macro should be
alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is
not an array.
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 8c5dde628405..bac01eec07a6 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -681,7 +681,7 @@ int nfit_spa_type(struct acpi_nfit_system_address *spa)
int i;
for (i = 0; i < NFIT_UUID_MAX; i++)
- if (guid_equal(to_nfit_uuid(i), (guid_t *)>range_guid))
+ if (guid_equal(to_nfit_uuid(i), cast_guid(spa->range_guid)))
return i;
return -1;
}
diff --git a/include/linux/uuid.h b/include/linux/uuid.h
index 8cdc0d3567cd..cec1dc2ab994 100644
--- a/include/linux/uuid.h
+++ b/include/linux/uuid.h
@@ -33,6 +33,9 @@ typedef struct {
extern const guid_t guid_null;
extern const uuid_t uuid_null;
+#define cast_guid(x) ({ BUILD_BUG_ON(ARRAY_SIZE(x) != 16); (guid_t *)&(x); })
+#define cast_uuid(x) ({ BUILD_BUG_ON(ARRAY_SIZE(x) != 16); (uuid_t *)&(x); })
+
static inline bool guid_equal(const guid_t *u1, const guid_t *u2)
{
return memcmp(u1, u2, sizeof(guid_t)) == 0;
[PATCH v1 1/1] ACPI: NFIT: Import GUID before use
Strictly speaking the comparison between guid_t and raw buffer
is not correct. Import GUID to variable of guid_t type and then
compare.
Signed-off-by: Andy Shevchenko
---
drivers/acpi/nfit/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 958aaac869e8..6d8a1a93636a 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -678,10 +678,12 @@ static const char *spa_type_name(u16 type)
int nfit_spa_type(struct acpi_nfit_system_address *spa)
{
+ guid_t guid;
int i;
+ import_guid(, spa->range_guid);
for (i = 0; i < NFIT_UUID_MAX; i++)
- if (guid_equal(to_nfit_uuid(i), (guid_t *)>range_guid))
+ if (guid_equal(to_nfit_uuid(i), ))
return i;
return -1;
}
--
2.30.2
