[PATCH] staging: vt665x: fix alignment constraints

[PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

Removing 2 instances of alignment warnings

drivers/staging/vt6655/rxtx.h:153:1: warning: alignment 1 of ‘struct vnt_cts’ is less than 2 [-Wpacked-not-aligned]
drivers/staging/vt6655/rxtx.h:163:1: warning: alignment 1 of ‘struct vnt_cts_fb’ is less than 2 [-Wpacked-not-aligned]

This patch is related to 2faf12c57ef (staging: vt665x: fix alignment constraints, 2021-02-04)

The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
this requires any encapsulating struct to also have an alignment of 2.

Signed-off-by: Edmundo Carmona Antoranz <eantoranz@gmail.com>
---
 drivers/staging/vt6655/rxtx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6655/rxtx.h b/drivers/staging/vt6655/rxtx.h
index e7061d383306..c3c2c1566882 100644
--- a/drivers/staging/vt6655/rxtx.h
+++ b/drivers/staging/vt6655/rxtx.h
@@ -150,7 +150,7 @@ struct vnt_cts {
 	u16 reserved;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_cts_fb {
 	struct vnt_phy_field b;
@@ -160,7 +160,7 @@ struct vnt_cts_fb {
 	__le16 cts_duration_ba_f1;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_tx_fifo_head {
 	u8 tx_key[WLAN_KEY_LEN_CCMP];
-- 
2.30.1

Re: [PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

On Thu, Mar 11, 2021 at 11:43 PM Edmundo Carmona Antoranz
<eantoranz@gmail.com> wrote:
>
> The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
> this requires any encapsulating struct to also have an alignment of 2.
>

To make sure of this, I played with an empty struct.

struct a {} __packed __aligned(2);

struct structb {
    struct a blah;
} __packed; <--- got a warning about alignment not being 2.

I would guess that setting the encapsulating struct to be __aligned(4)
or higher would also work fine, don't know if I should be more
thorough in that regard in the patch comment.

Re: [PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

On Fri, Mar 12, 2021 at 6:50 AM Edmundo Carmona Antoranz
<eantoranz@gmail.com> wrote:
>
> On Thu, Mar 11, 2021 at 11:43 PM Edmundo Carmona Antoranz
> <eantoranz@gmail.com> wrote:
> >
> > The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
> > this requires any encapsulating struct to also have an alignment of 2.
> >
>
> To make sure of this, I played with an empty struct.
>
> struct a {} __packed __aligned(2);
>
> struct structb {
>     struct a blah;
> } __packed; <--- got a warning about alignment not being 2.
>
> I would guess that setting the encapsulating struct to be __aligned(4)
> or higher would also work fine, don't know if I should be more
> thorough in that regard in the patch comment.

I think the patch description is clear enough, but it would help to include
a reference to my earlier patch that tried to fix the problem before. I don't
know why this came back now, maybe my patch was incomplete to start
with, or an extra alignment constraint was added to a second indirectly
included structure.

      Arnd

Re: [PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

On Fri, Mar 12, 2021 at 3:19 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
>
> I think the patch description is clear enough, but it would help to include
> a reference to my earlier patch that tried to fix the problem before. I don't

Great! I did mention it in the preceding line to the section I replied
to, though. It has it in the patch:

"""
This patch is related to 2faf12c57ef (staging: vt665x: fix alignment
constraints, 2021-02-04)

The root cause seems to be that _because_ struct ieee80211_cts is
marked as __aligned(2),
this requires any encapsulating struct to also have an alignment of 2.
"""

Maybe it needs to be formatted in a different fashion? Should I use a
longer (like 11 chars, maybe) ID?

Re: [PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

On Fri, Mar 12, 2021 at 1:56 PM Edmundo Carmona Antoranz
<eantoranz@gmail.com> wrote:
>
> On Fri, Mar 12, 2021 at 3:19 AM Arnd Bergmann <arnd@arndb.de> wrote:
> >
> >
> > I think the patch description is clear enough, but it would help to include
> > a reference to my earlier patch that tried to fix the problem before. I don't
>
> Great! I did mention it in the preceding line to the section I replied
> to, though. It has it in the patch:
>
> """
> This patch is related to 2faf12c57ef (staging: vt665x: fix alignment
> constraints, 2021-02-04)
>
> The root cause seems to be that _because_ struct ieee80211_cts is
> marked as __aligned(2),
> this requires any encapsulating struct to also have an alignment of 2.
> """
>
> Maybe it needs to be formatted in a different fashion? Should I use a
> longer (like 11 chars, maybe) ID?

My mistake. The normal references use 12-character IDs, but in this
case I just missed it because it was in the cleartext.

I would normally use a separate 'Fixes:' line for this.

       Arnd

Re: [PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

On Fri, Mar 12, 2021 at 8:32 AM Arnd Bergmann <arnd@arndb.de> wrote:
> My mistake. The normal references use 12-character IDs, but in this
> case I just missed it because it was in the cleartext.
>
> I would normally use a separate 'Fixes:' line for this.
>

Oh, ok. Let me see its formatting and then I'll send a [PATCH v2]

Re: [PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

On Tue, Mar 16, 2021 at 7:17 PM Edmundo Carmona Antoranz
<eantoranz@gmail.com> wrote:
>
> Removing 2 instances of alignment warnings
>
> drivers/staging/vt6655/rxtx.h:153:1: warning: alignment 1 of ‘struct vnt_cts’ is less than 2 [-Wpacked-not-aligned]
> drivers/staging/vt6655/rxtx.h:163:1: warning: alignment 1 of ‘struct vnt_cts_fb’ is less than 2 [-Wpacked-not-aligned]
>
> The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
> this requires any encapsulating struct to also have an alignment of 2.
>
> Fixes: 2faf12c57efe ("staging: vt665x: fix alignment constraints")
> Signed-off-by: Edmundo Carmona Antoranz <eantoranz@gmail.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

On Tue, Mar 16, 2021 at 7:17 PM Edmundo Carmona Antoranz
<eantoranz@gmail.com> wrote:
>
> Removing 2 instances of alignment warnings
>
> drivers/staging/vt6655/rxtx.h:153:1: warning: alignment 1 of ‘struct vnt_cts’ is less than 2 [-Wpacked-not-aligned]
> drivers/staging/vt6655/rxtx.h:163:1: warning: alignment 1 of ‘struct vnt_cts_fb’ is less than 2 [-Wpacked-not-aligned]
>
> The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
> this requires any encapsulating struct to also have an alignment of 2.
>
> Fixes: 2faf12c57efe ("staging: vt665x: fix alignment constraints")
> Signed-off-by: Edmundo Carmona Antoranz <eantoranz@gmail.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
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[PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

Removing 2 instances of alignment warnings

drivers/staging/vt6655/rxtx.h:153:1: warning: alignment 1 of ‘struct vnt_cts’ is less than 2 [-Wpacked-not-aligned]
drivers/staging/vt6655/rxtx.h:163:1: warning: alignment 1 of ‘struct vnt_cts_fb’ is less than 2 [-Wpacked-not-aligned]

The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
this requires any encapsulating struct to also have an alignment of 2.

Fixes: 2faf12c57efe ("staging: vt665x: fix alignment constraints")
Signed-off-by: Edmundo Carmona Antoranz <eantoranz@gmail.com>
---
 drivers/staging/vt6655/rxtx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6655/rxtx.h b/drivers/staging/vt6655/rxtx.h
index e7061d383306..c3c2c1566882 100644
--- a/drivers/staging/vt6655/rxtx.h
+++ b/drivers/staging/vt6655/rxtx.h
@@ -150,7 +150,7 @@ struct vnt_cts {
 	u16 reserved;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_cts_fb {
 	struct vnt_phy_field b;
@@ -160,7 +160,7 @@ struct vnt_cts_fb {
 	__le16 cts_duration_ba_f1;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_tx_fifo_head {
 	u8 tx_key[WLAN_KEY_LEN_CCMP];
-- 
2.30.2

[PATCH] staging: vt665x: fix alignment constraints

[Edmundo Carmona Antoranz]

Removing 2 instances of alignment warnings

drivers/staging/vt6655/rxtx.h:153:1: warning: alignment 1 of ‘struct vnt_cts’ is less than 2 [-Wpacked-not-aligned]
drivers/staging/vt6655/rxtx.h:163:1: warning: alignment 1 of ‘struct vnt_cts_fb’ is less than 2 [-Wpacked-not-aligned]

The root cause seems to be that _because_ struct ieee80211_cts is marked as __aligned(2),
this requires any encapsulating struct to also have an alignment of 2.

Fixes: 2faf12c57efe ("staging: vt665x: fix alignment constraints")
Signed-off-by: Edmundo Carmona Antoranz <eantoranz@gmail.com>
---
 drivers/staging/vt6655/rxtx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6655/rxtx.h b/drivers/staging/vt6655/rxtx.h
index e7061d383306..c3c2c1566882 100644
--- a/drivers/staging/vt6655/rxtx.h
+++ b/drivers/staging/vt6655/rxtx.h
@@ -150,7 +150,7 @@ struct vnt_cts {
 	u16 reserved;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_cts_fb {
 	struct vnt_phy_field b;
@@ -160,7 +160,7 @@ struct vnt_cts_fb {
 	__le16 cts_duration_ba_f1;
 	struct ieee80211_cts data;
 	u16 reserved2;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_tx_fifo_head {
 	u8 tx_key[WLAN_KEY_LEN_CCMP];
-- 
2.30.2

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[PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

multiple structures contains a ieee80211_rts structure, which is required to
have at least two byte alignment, but are annotated with a __packed attribute
to force single-byte alignment:

staging/vt6656/rxtx.h:98:1: warning: alignment 1 of 'struct vnt_rts_g' is less than 2 [-Wpacked-not-aligned]
staging/vt6656/rxtx.h:106:1: warning: alignment 1 of 'struct vnt_rts_ab' is less than 2 [-Wpacked-not-aligned]
staging/vt6656/rxtx.h:116:1: warning: alignment 1 of 'struct vnt_cts' is less than 2 [-Wpacked-not-aligned]

I see no reason why the structure itself would be misaligned, and all members
have at least two-byte alignment within the structure, so use the same
constraint on the sturcture itself.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/vt6655/rxtx.h | 8 ++++----
 drivers/staging/vt6656/rxtx.h | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/vt6655/rxtx.h b/drivers/staging/vt6655/rxtx.h
index 464dd89078b2..e7061d383306 100644
--- a/drivers/staging/vt6655/rxtx.h
+++ b/drivers/staging/vt6655/rxtx.h
@@ -111,7 +111,7 @@ struct vnt_rts_g {
 	__le16 duration_bb;
 	u16 reserved;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_g_fb {
 	struct vnt_phy_field b;
@@ -125,14 +125,14 @@ struct vnt_rts_g_fb {
 	__le16 rts_duration_ba_f1;
 	__le16 rts_duration_aa_f1;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_ab {
 	struct vnt_phy_field ab;
 	__le16 duration;
 	u16 reserved;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_a_fb {
 	struct vnt_phy_field a;
@@ -141,7 +141,7 @@ struct vnt_rts_a_fb {
 	__le16 rts_duration_f0;
 	__le16 rts_duration_f1;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 /* CTS buffer header */
 struct vnt_cts {
diff --git a/drivers/staging/vt6656/rxtx.h b/drivers/staging/vt6656/rxtx.h
index 6ca2ca32d036..f23440799443 100644
--- a/drivers/staging/vt6656/rxtx.h
+++ b/drivers/staging/vt6656/rxtx.h
@@ -95,7 +95,7 @@ struct vnt_rts_g {
 	u16 wReserved;
 	struct ieee80211_rts data;
 	struct vnt_tx_datahead_g data_head;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_ab {
 	struct vnt_phy_field ab;
@@ -103,7 +103,7 @@ struct vnt_rts_ab {
 	u16 wReserved;
 	struct ieee80211_rts data;
 	struct vnt_tx_datahead_ab data_head;
-} __packed;
+} __packed __aligned(2);
 
 /* CTS buffer header */
 struct vnt_cts {
@@ -113,7 +113,7 @@ struct vnt_cts {
 	struct ieee80211_cts data;
 	u16 reserved2;
 	struct vnt_tx_datahead_g data_head;
-} __packed;
+} __packed __aligned(2);
 
 union vnt_tx_data_head {
 	/* rts g */
-- 
2.29.2

[PATCH] staging: vt665x: fix alignment constraints

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

multiple structures contains a ieee80211_rts structure, which is required to
have at least two byte alignment, but are annotated with a __packed attribute
to force single-byte alignment:

staging/vt6656/rxtx.h:98:1: warning: alignment 1 of 'struct vnt_rts_g' is less than 2 [-Wpacked-not-aligned]
staging/vt6656/rxtx.h:106:1: warning: alignment 1 of 'struct vnt_rts_ab' is less than 2 [-Wpacked-not-aligned]
staging/vt6656/rxtx.h:116:1: warning: alignment 1 of 'struct vnt_cts' is less than 2 [-Wpacked-not-aligned]

I see no reason why the structure itself would be misaligned, and all members
have at least two-byte alignment within the structure, so use the same
constraint on the sturcture itself.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/vt6655/rxtx.h | 8 ++++----
 drivers/staging/vt6656/rxtx.h | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/vt6655/rxtx.h b/drivers/staging/vt6655/rxtx.h
index 464dd89078b2..e7061d383306 100644
--- a/drivers/staging/vt6655/rxtx.h
+++ b/drivers/staging/vt6655/rxtx.h
@@ -111,7 +111,7 @@ struct vnt_rts_g {
 	__le16 duration_bb;
 	u16 reserved;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_g_fb {
 	struct vnt_phy_field b;
@@ -125,14 +125,14 @@ struct vnt_rts_g_fb {
 	__le16 rts_duration_ba_f1;
 	__le16 rts_duration_aa_f1;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_ab {
 	struct vnt_phy_field ab;
 	__le16 duration;
 	u16 reserved;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_a_fb {
 	struct vnt_phy_field a;
@@ -141,7 +141,7 @@ struct vnt_rts_a_fb {
 	__le16 rts_duration_f0;
 	__le16 rts_duration_f1;
 	struct ieee80211_rts data;
-} __packed;
+} __packed __aligned(2);
 
 /* CTS buffer header */
 struct vnt_cts {
diff --git a/drivers/staging/vt6656/rxtx.h b/drivers/staging/vt6656/rxtx.h
index 6ca2ca32d036..f23440799443 100644
--- a/drivers/staging/vt6656/rxtx.h
+++ b/drivers/staging/vt6656/rxtx.h
@@ -95,7 +95,7 @@ struct vnt_rts_g {
 	u16 wReserved;
 	struct ieee80211_rts data;
 	struct vnt_tx_datahead_g data_head;
-} __packed;
+} __packed __aligned(2);
 
 struct vnt_rts_ab {
 	struct vnt_phy_field ab;
@@ -103,7 +103,7 @@ struct vnt_rts_ab {
 	u16 wReserved;
 	struct ieee80211_rts data;
 	struct vnt_tx_datahead_ab data_head;
-} __packed;
+} __packed __aligned(2);
 
 /* CTS buffer header */
 struct vnt_cts {
@@ -113,7 +113,7 @@ struct vnt_cts {
 	struct ieee80211_cts data;
 	u16 reserved2;
 	struct vnt_tx_datahead_g data_head;
-} __packed;
+} __packed __aligned(2);
 
 union vnt_tx_data_head {
 	/* rts g */
-- 
2.29.2

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