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[next] wifi: ath11k: Avoid -Wflex-array-member-not-at-end warnings

Message ID ZrZB3Rjswe0ZXtug@cute
State New
Headers show
Series [next] wifi: ath11k: Avoid -Wflex-array-member-not-at-end warnings | expand

Commit Message

Gustavo A. R. Silva Aug. 9, 2024, 4:20 p.m. UTC
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Move the conflicting declaration to the end of the structure. Notice
that `struct ieee80211_chanctx_conf` is a flexible structure --a
structure that contains a flexible-array member.

Also, remove a couple of unused structures.

Fix the following warnings:
drivers/net/wireless/ath/ath11k/core.h:409:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/ath/ath11k/dp.h:1309:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/ath/ath11k/dp.h:1368:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/wireless/ath/ath11k/core.h |  4 +++-
 drivers/net/wireless/ath/ath11k/dp.h   | 23 -----------------------
 2 files changed, 3 insertions(+), 24 deletions(-)

Comments

Gustavo A. R. Silva Aug. 10, 2024, 3:41 p.m. UTC | #1
On 09/08/24 20:21, Jeff Johnson wrote:
> On 8/9/2024 9:20 AM, Gustavo A. R. Silva wrote:
>> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
>> getting ready to enable it, globally.
>>
>> Move the conflicting declaration to the end of the structure. Notice
>> that `struct ieee80211_chanctx_conf` is a flexible structure --a
>> structure that contains a flexible-array member.
>>
>> Also, remove a couple of unused structures.
>>
>> Fix the following warnings:
>> drivers/net/wireless/ath/ath11k/core.h:409:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>> drivers/net/wireless/ath/ath11k/dp.h:1309:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>> drivers/net/wireless/ath/ath11k/dp.h:1368:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>> ---
>>   drivers/net/wireless/ath/ath11k/core.h |  4 +++-
>>   drivers/net/wireless/ath/ath11k/dp.h   | 23 -----------------------
>>   2 files changed, 3 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
>> index df24f0e409af..e283415dccf3 100644
>> --- a/drivers/net/wireless/ath/ath11k/core.h
>> +++ b/drivers/net/wireless/ath/ath11k/core.h
>> @@ -406,11 +406,13 @@ struct ath11k_vif {
>>   	bool wpaie_present;
>>   	bool bcca_zero_sent;
>>   	bool do_not_send_tmpl;
>> -	struct ieee80211_chanctx_conf chanctx;
>>   	struct ath11k_arp_ns_offload arp_ns_offload;
>>   	struct ath11k_rekey_data rekey_data;
>>   
>>   	struct ath11k_reg_tpc_power_info reg_tpc_info;
>> +
>> +	/* Must be last - ends in a flexible-array member. */
>> +	struct ieee80211_chanctx_conf chanctx;
> 
> there is something illogical about this since the vif is allocated using
> sizeof() and hence there will never be memory allocated for the flexible
> array, and it is assigned using either struct assignment or memcpy using the
> struct size which (fortunately) would not transfer the flexible array contents:
> 		arvif->chanctx = *ctx;
> 
> 		memcpy(&arvif->chanctx, ctx, sizeof(*ctx));

Yes; this is why I didn't include a 'Fixes' tag.

In any case, middle-flex-arrays are deprecated and should either be
removed/refactored[1][2] or placed at the very bottom in any nested
structures. :)

> 
> since ath11k doesn't actually use the drv_priv[] I guess this change is OK, it
> is just strange to me.
> 
> also makes me wonder why ath11k keeps a copy of the chanctx instead of just
> getting it from the underlying ieee80211_link_data. but that is outside the
> scope of this discussion.
> 
>>   };
>>   
>>   struct ath11k_vif_iter {
>> diff --git a/drivers/net/wireless/ath/ath11k/dp.h b/drivers/net/wireless/ath/ath11k/dp.h
>> index 2f6dd69d3be2..65d2bc0687c8 100644
>> --- a/drivers/net/wireless/ath/ath11k/dp.h
>> +++ b/drivers/net/wireless/ath/ath11k/dp.h
>> @@ -1305,18 +1305,6 @@ struct htt_ppdu_stats_user_rate {
>>   #define HTT_TX_INFO_PEERID(_flags) \
>>   			FIELD_GET(HTT_PPDU_STATS_TX_INFO_FLAGS_PEERID_M, _flags)
>>   
>> -struct htt_tx_ppdu_stats_info {
>> -	struct htt_tlv tlv_hdr;
>> -	u32 tx_success_bytes;
>> -	u32 tx_retry_bytes;
>> -	u32 tx_failed_bytes;
>> -	u32 flags; /* %HTT_PPDU_STATS_TX_INFO_FLAGS_ */
>> -	u16 tx_success_msdus;
>> -	u16 tx_retry_msdus;
>> -	u16 tx_failed_msdus;
>> -	u16 tx_duration; /* united in us */
>> -} __packed;
>> -
>>   enum  htt_ppdu_stats_usr_compln_status {
>>   	HTT_PPDU_STATS_USER_STATUS_OK,
>>   	HTT_PPDU_STATS_USER_STATUS_FILTERED,
>> @@ -1364,17 +1352,6 @@ struct htt_ppdu_stats_usr_cmpltn_ack_ba_status {
>>   	u32 success_bytes;
>>   } __packed;
>>   
>> -struct htt_ppdu_stats_usr_cmn_array {
>> -	struct htt_tlv tlv_hdr;
>> -	u32 num_ppdu_stats;
>> -	/* tx_ppdu_stats_info is filled by multiple struct htt_tx_ppdu_stats_info
>> -	 * elements.
>> -	 * tx_ppdu_stats_info is variable length, with length =
>> -	 *     number_of_ppdu_stats * sizeof (struct htt_tx_ppdu_stats_info)
>> -	 */
>> -	struct htt_tx_ppdu_stats_info tx_ppdu_info[];
>> -} __packed;
>> -
>>   struct htt_ppdu_user_stats {
>>   	u16 peer_id;
>>   	u32 tlv_flags;
> 
> the second part if definitely ok.
> 
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>

Thanks
--
Gustavo

[1] https://lore.kernel.org/linux-hardening/ZrOQa2gew5yadyt3@cute/
[2] https://lore.kernel.org/linux-hardening/ZrJqtUpCI+uCeb4D@cute/
Kalle Valo Aug. 22, 2024, 4:50 p.m. UTC | #2
Jeff Johnson <quic_jjohnson@quicinc.com> writes:

> On 8/9/2024 9:20 AM, Gustavo A. R. Silva wrote:
>
>> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
>> getting ready to enable it, globally.
>> 
>> Move the conflicting declaration to the end of the structure. Notice
>> that `struct ieee80211_chanctx_conf` is a flexible structure --a
>> structure that contains a flexible-array member.
>> 
>> Also, remove a couple of unused structures.
>> 
>> Fix the following warnings:
>> drivers/net/wireless/ath/ath11k/core.h:409:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>> drivers/net/wireless/ath/ath11k/dp.h:1309:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>> drivers/net/wireless/ath/ath11k/dp.h:1368:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>> 
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>> ---
>>  drivers/net/wireless/ath/ath11k/core.h |  4 +++-
>>  drivers/net/wireless/ath/ath11k/dp.h   | 23 -----------------------
>>  2 files changed, 3 insertions(+), 24 deletions(-)
>> 
>> diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
>> index df24f0e409af..e283415dccf3 100644
>> --- a/drivers/net/wireless/ath/ath11k/core.h
>> +++ b/drivers/net/wireless/ath/ath11k/core.h
>> @@ -406,11 +406,13 @@ struct ath11k_vif {
>>  	bool wpaie_present;
>>  	bool bcca_zero_sent;
>>  	bool do_not_send_tmpl;
>> -	struct ieee80211_chanctx_conf chanctx;
>>  	struct ath11k_arp_ns_offload arp_ns_offload;
>>  	struct ath11k_rekey_data rekey_data;
>>  
>>  	struct ath11k_reg_tpc_power_info reg_tpc_info;
>> +
>> +	/* Must be last - ends in a flexible-array member. */
>> +	struct ieee80211_chanctx_conf chanctx;
>
> there is something illogical about this since the vif is allocated using
> sizeof() and hence there will never be memory allocated for the flexible
> array, and it is assigned using either struct assignment or memcpy using the
> struct size which (fortunately) would not transfer the flexible array contents:
> 		arvif->chanctx = *ctx;
>
> 		memcpy(&arvif->chanctx, ctx, sizeof(*ctx));
>
> since ath11k doesn't actually use the drv_priv[] I guess this change is OK, it
> is just strange to me.
>
> also makes me wonder why ath11k keeps a copy of the chanctx instead of just
> getting it from the underlying ieee80211_link_data. but that is outside the
> scope of this discussion.

Yeah, this doesn't look right. I don't think a driver should be copying
struct ieee80211_chanctx_conf like that. I think I'll add a comment
about this to the code:

/* FIXME: Driver should not copy struct ieee80211_chanctx_conf,
 * especially because it has a flexible array. Find a better way.
 */

Thoughts?
Kalle Valo Sept. 5, 2024, 4:20 p.m. UTC | #3
"Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:

> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
> 
> Move the conflicting declaration to the end of the structure. Notice
> that `struct ieee80211_chanctx_conf` is a flexible structure --a
> structure that contains a flexible-array member.
> 
> Also, remove a couple of unused structures.
> 
> Fix the following warnings:
> drivers/net/wireless/ath/ath11k/core.h:409:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> drivers/net/wireless/ath/ath11k/dp.h:1309:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> drivers/net/wireless/ath/ath11k/dp.h:1368:24: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

820aa897837f wifi: ath11k: Avoid -Wflex-array-member-not-at-end warnings
diff mbox series

Patch

diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
index df24f0e409af..e283415dccf3 100644
--- a/drivers/net/wireless/ath/ath11k/core.h
+++ b/drivers/net/wireless/ath/ath11k/core.h
@@ -406,11 +406,13 @@  struct ath11k_vif {
 	bool wpaie_present;
 	bool bcca_zero_sent;
 	bool do_not_send_tmpl;
-	struct ieee80211_chanctx_conf chanctx;
 	struct ath11k_arp_ns_offload arp_ns_offload;
 	struct ath11k_rekey_data rekey_data;
 
 	struct ath11k_reg_tpc_power_info reg_tpc_info;
+
+	/* Must be last - ends in a flexible-array member. */
+	struct ieee80211_chanctx_conf chanctx;
 };
 
 struct ath11k_vif_iter {
diff --git a/drivers/net/wireless/ath/ath11k/dp.h b/drivers/net/wireless/ath/ath11k/dp.h
index 2f6dd69d3be2..65d2bc0687c8 100644
--- a/drivers/net/wireless/ath/ath11k/dp.h
+++ b/drivers/net/wireless/ath/ath11k/dp.h
@@ -1305,18 +1305,6 @@  struct htt_ppdu_stats_user_rate {
 #define HTT_TX_INFO_PEERID(_flags) \
 			FIELD_GET(HTT_PPDU_STATS_TX_INFO_FLAGS_PEERID_M, _flags)
 
-struct htt_tx_ppdu_stats_info {
-	struct htt_tlv tlv_hdr;
-	u32 tx_success_bytes;
-	u32 tx_retry_bytes;
-	u32 tx_failed_bytes;
-	u32 flags; /* %HTT_PPDU_STATS_TX_INFO_FLAGS_ */
-	u16 tx_success_msdus;
-	u16 tx_retry_msdus;
-	u16 tx_failed_msdus;
-	u16 tx_duration; /* united in us */
-} __packed;
-
 enum  htt_ppdu_stats_usr_compln_status {
 	HTT_PPDU_STATS_USER_STATUS_OK,
 	HTT_PPDU_STATS_USER_STATUS_FILTERED,
@@ -1364,17 +1352,6 @@  struct htt_ppdu_stats_usr_cmpltn_ack_ba_status {
 	u32 success_bytes;
 } __packed;
 
-struct htt_ppdu_stats_usr_cmn_array {
-	struct htt_tlv tlv_hdr;
-	u32 num_ppdu_stats;
-	/* tx_ppdu_stats_info is filled by multiple struct htt_tx_ppdu_stats_info
-	 * elements.
-	 * tx_ppdu_stats_info is variable length, with length =
-	 *     number_of_ppdu_stats * sizeof (struct htt_tx_ppdu_stats_info)
-	 */
-	struct htt_tx_ppdu_stats_info tx_ppdu_info[];
-} __packed;
-
 struct htt_ppdu_user_stats {
 	u16 peer_id;
 	u32 tlv_flags;