[PATCH net-next v1 0/7] net: hsr: subsystem cleanups and modernization

[PATCH net-next v1 0/7] net: hsr: subsystem cleanups and modernization

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

This patch series performs a general cleanup and modernization of the 
HSR(High-availability Seamless Redundancy) protocol driver. Since the 
HSR subsystem is currently orphaned, these changes aim to bring the 
code up to modern kernel standards and improve overall maintainability.

Luka Gejak (7):
  net: hsr: constify hsr_ops and prp_ops protocol operation structures
  net: hsr: replace fallthrough comments with fallthrough macro
  net: hsr: remove unnecessary void function return statement
  net: hsr: use __func__ instead of hardcoded function name
  net: hsr: remove unnecessary braces for single statement block
  net: hsr: add missing blank lines after function declarations
  net: hsr: use BIT() macro for bit shift constant

 net/hsr/hsr_device.c   |  5 ++---
 net/hsr/hsr_forward.c  |  2 +-
 net/hsr/hsr_framereg.c |  3 +--
 net/hsr/hsr_framereg.h |  2 +-
 net/hsr/hsr_main.h     | 23 ++++++++++++++++++-----
 net/hsr/hsr_netlink.c  |  4 ++--
 6 files changed, 25 insertions(+), 14 deletions(-)

-- 
2.53.0

[PATCH net-next v1 1/7] net: hsr: constify hsr_ops and prp_ops protocol operation structures

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

The hsr_ops and prp_ops structures are assigned to hsr->proto_ops during
device initialization and are never modified at runtime. Declaring them
as const allows the compiler to place these structures in read-only
memory, which improves security by preventing accidental or malicious
modification of the function pointers they contain.

The proto_ops field in struct hsr_priv is also updated to a const
pointer to maintain type consistency.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_device.c | 4 ++--
 net/hsr/hsr_main.h   | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index 5c3eca2235ce..90236028817d 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -616,7 +616,7 @@ static const struct device_type hsr_type = {
 	.name = "hsr",
 };
 
-static struct hsr_proto_ops hsr_ops = {
+static const struct hsr_proto_ops hsr_ops = {
 	.send_sv_frame = send_hsr_supervision_frame,
 	.create_tagged_frame = hsr_create_tagged_frame,
 	.get_untagged_frame = hsr_get_untagged_frame,
@@ -626,7 +626,7 @@ static struct hsr_proto_ops hsr_ops = {
 	.register_frame_out = hsr_register_frame_out,
 };
 
-static struct hsr_proto_ops prp_ops = {
+static const struct hsr_proto_ops prp_ops = {
 	.send_sv_frame = send_prp_supervision_frame,
 	.create_tagged_frame = prp_create_tagged_frame,
 	.get_untagged_frame = prp_get_untagged_frame,
diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 33b0d2460c9b..134e4f3fff60 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -202,7 +202,7 @@ struct hsr_priv {
 	enum hsr_version prot_version;	/* Indicate if HSRv0, HSRv1 or PRPv1 */
 	spinlock_t seqnr_lock;	/* locking for sequence_nr */
 	spinlock_t list_lock;	/* locking for node list */
-	struct hsr_proto_ops	*proto_ops;
+	const struct hsr_proto_ops	*proto_ops;
 #define PRP_LAN_ID	0x5     /* 0x1010 for A and 0x1011 for B. Bit 0 is set
 				 * based on SLAVE_A or SLAVE_B
 				 */
-- 
2.53.0

[PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Replace two instances of the legacy '/* Fall through */' comment with the
standardized 'fallthrough;' macro in hsr_get_node_status() and
hsr_get_node_list(). The kernel has standardized on the fallthrough macro
since the migration from comment-based annotations, which provides
compiler-level verification of intentional case fall-throughs.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_netlink.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index db0b0af7a692..32c1b77cf84b 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -433,7 +433,7 @@ static int hsr_get_node_status(struct sk_buff *skb_in, struct genl_info *info)
 
 nla_put_failure:
 	kfree_skb(skb_out);
-	/* Fall through */
+	fallthrough;
 
 fail:
 	rcu_read_unlock();
@@ -524,7 +524,7 @@ static int hsr_get_node_list(struct sk_buff *skb_in, struct genl_info *info)
 
 nla_put_failure:
 	nlmsg_free(skb_out);
-	/* Fall through */
+	fallthrough;
 
 fail:
 	rcu_read_unlock();
-- 
2.53.0

[PATCH net-next v1 3/7] net: hsr: remove unnecessary void function return statement

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Remove the trailing 'return;' from the end of the void function
send_hsr_supervision_frame() per checkpatch recommendations.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_device.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index 90236028817d..6ffecc3f0004 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -363,7 +363,6 @@ static void send_hsr_supervision_frame(struct hsr_port *port,
 
 	hsr_forward_skb(skb, port);
 	spin_unlock_bh(&hsr->seqnr_lock);
-	return;
 }
 
 static void send_prp_supervision_frame(struct hsr_port *master,
-- 
2.53.0

[PATCH net-next v1 4/7] net: hsr: use __func__ instead of hardcoded function name

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Replace the hardcoded string "hsr_get_untagged_frame" with the
standard __func__ macro in netdev_warn_once() call to make the code
more robust to refactoring.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_forward.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index aefc9b6936ba..0aca859c88cb 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -184,7 +184,7 @@ struct sk_buff *hsr_get_untagged_frame(struct hsr_frame_info *frame,
 				create_stripped_skb_hsr(frame->skb_hsr, frame);
 		else
 			netdev_warn_once(port->dev,
-					 "Unexpected frame received in hsr_get_untagged_frame()\n");
+					 "Unexpected frame received in %s()\n", __func__);
 
 		if (!frame->skb_std)
 			return NULL;
-- 
2.53.0

[PATCH net-next v1 5/7] net: hsr: remove unnecessary braces for single statement block

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Remove the unnecessary curly braces around the single statement
for loop body in hsr_add_node() as per kernel coding style.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_framereg.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index 577fb588bc2f..9c3b7381788e 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -182,9 +182,8 @@ static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 	 * as initialization. (0 could trigger an spurious ring error warning).
 	 */
 	now = jiffies;
-	for (i = 0; i < HSR_PT_PORTS; i++) {
+	for (i = 0; i < HSR_PT_PORTS; i++)
 		new_node->time_in[i] = now;
-	}
 
 	if (san && hsr->proto_ops->handle_san_frame)
 		hsr->proto_ops->handle_san_frame(san, rx_port, new_node);
-- 
2.53.0

[PATCH net-next v1 6/7] net: hsr: add missing blank lines after function declarations

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Add missing blank lines after the inline function declarations to
comply with the kernel coding style guidelines.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_main.h | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 134e4f3fff60..202dc90bd2ab 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -143,6 +143,7 @@ static inline void set_prp_lan_id(struct prp_rct *rct, u16 lan_id)
 	rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
 					  0x0FFF) | (lan_id << 12));
 }
+
 static inline void set_prp_LSDU_size(struct prp_rct *rct, u16 LSDU_size)
 {
 	rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
@@ -277,24 +278,36 @@ static inline bool prp_check_lsdu_size(struct sk_buff *skb,
 }
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
+
 void hsr_debugfs_rename(struct net_device *dev);
 void hsr_debugfs_init(struct hsr_priv *priv, struct net_device *hsr_dev);
 void hsr_debugfs_term(struct hsr_priv *priv);
 void hsr_debugfs_create_root(void);
 void hsr_debugfs_remove_root(void);
+
 #else
+
 static inline void hsr_debugfs_rename(struct net_device *dev)
 {
 }
+
 static inline void hsr_debugfs_init(struct hsr_priv *priv,
 				    struct net_device *hsr_dev)
-{}
+{
+}
+
 static inline void hsr_debugfs_term(struct hsr_priv *priv)
-{}
+{
+}
+
 static inline void hsr_debugfs_create_root(void)
-{}
+{
+}
+
 static inline void hsr_debugfs_remove_root(void)
-{}
+{
+}
+
 #endif
 
 #endif /*  __HSR_PRIVATE_H */
-- 
2.53.0

[PATCH net-next v1 7/7] net: hsr: use BIT() macro for bit shift constant

[luka.gejak]

From: Luka Gejak <luka.gejak@linux.dev>

Replace the explicit bit shift (1 << HSR_SEQ_BLOCK_SHIFT) with the
standardized BIT() macro for defining HSR_SEQ_BLOCK_SIZE. This improves
readability and aligns with kernel coding conventions.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
 net/hsr/hsr_framereg.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/hsr/hsr_framereg.h b/net/hsr/hsr_framereg.h
index c65ecb925734..cb731ee0ce5c 100644
--- a/net/hsr/hsr_framereg.h
+++ b/net/hsr/hsr_framereg.h
@@ -79,7 +79,7 @@ struct hsr_seq_block *hsr_get_seq_block(struct hsr_node *node, u16 block_idx);
 #endif
 
 #define HSR_SEQ_BLOCK_SHIFT 7 /* 128 bits */
-#define HSR_SEQ_BLOCK_SIZE (1 << HSR_SEQ_BLOCK_SHIFT)
+#define HSR_SEQ_BLOCK_SIZE BIT(HSR_SEQ_BLOCK_SHIFT)
 #define HSR_SEQ_BLOCK_MASK (HSR_SEQ_BLOCK_SIZE - 1)
 #define HSR_MAX_SEQ_BLOCKS 64
 
-- 
2.53.0

Re: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro

[kernel test robot]

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/luka-gejak-linux-dev/net-hsr-constify-hsr_ops-and-prp_ops-protocol-operation-structures/20260326-143638
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260324144630.189094-3-luka.gejak%40linux.dev
patch subject: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260326/202603261419.jqhvfAVi-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260326/202603261419.jqhvfAVi-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603261419.jqhvfAVi-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/compiler_types.h:88,
                    from <command-line>:
   net/hsr/hsr_netlink.c: In function 'hsr_get_node_status':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                         ^~~~~~~~~~~~~
   net/hsr/hsr_netlink.c:436:9: note: in expansion of macro 'fallthrough'
     436 |         fallthrough;
         |         ^~~~~~~~~~~
   net/hsr/hsr_netlink.c: In function 'hsr_get_node_list':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                         ^~~~~~~~~~~~~
   net/hsr/hsr_netlink.c:527:9: note: in expansion of macro 'fallthrough'
     527 |         fallthrough;
         |         ^~~~~~~~~~~
--
   In file included from include/linux/compiler_types.h:88,
                    from <command-line>:
   hsr_netlink.c: In function 'hsr_get_node_status':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                         ^~~~~~~~~~~~~
   hsr_netlink.c:436:9: note: in expansion of macro 'fallthrough'
     436 |         fallthrough;
         |         ^~~~~~~~~~~
   hsr_netlink.c: In function 'hsr_get_node_list':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                         ^~~~~~~~~~~~~
   hsr_netlink.c:527:9: note: in expansion of macro 'fallthrough'
     527 |         fallthrough;
         |         ^~~~~~~~~~~


vim +/fallthrough +214 include/linux/compiler_attributes.h

294f69e662d157 Joe Perches   2019-10-05  201  
294f69e662d157 Joe Perches   2019-10-05  202  /*
294f69e662d157 Joe Perches   2019-10-05  203   * Add the pseudo keyword 'fallthrough' so case statement blocks
294f69e662d157 Joe Perches   2019-10-05  204   * must end with any of these keywords:
294f69e662d157 Joe Perches   2019-10-05  205   *   break;
294f69e662d157 Joe Perches   2019-10-05  206   *   fallthrough;
ca0760e7d79e2b Wei Ming Chen 2021-05-06  207   *   continue;
294f69e662d157 Joe Perches   2019-10-05  208   *   goto <label>;
294f69e662d157 Joe Perches   2019-10-05  209   *   return [expression];
294f69e662d157 Joe Perches   2019-10-05  210   *
294f69e662d157 Joe Perches   2019-10-05  211   *  gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes
294f69e662d157 Joe Perches   2019-10-05  212   */
294f69e662d157 Joe Perches   2019-10-05  213  #if __has_attribute(__fallthrough__)
294f69e662d157 Joe Perches   2019-10-05 @214  # define fallthrough                    __attribute__((__fallthrough__))
294f69e662d157 Joe Perches   2019-10-05  215  #else
294f69e662d157 Joe Perches   2019-10-05  216  # define fallthrough                    do {} while (0)  /* fallthrough */
a3f8a30f3f0079 Miguel Ojeda  2018-08-30  217  #endif
a3f8a30f3f0079 Miguel Ojeda  2018-08-30  218  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net-next v1 0/7] net: hsr: subsystem cleanups and modernization

[Felix Maurer]

On Tue, Mar 24, 2026 at 03:46:23PM +0100, luka.gejak@linux.dev wrote:
> From: Luka Gejak <luka.gejak@linux.dev>
>
> This patch series performs a general cleanup and modernization of the
> HSR(High-availability Seamless Redundancy) protocol driver. Since the
> HSR subsystem is currently orphaned, these changes aim to bring the
> code up to modern kernel standards and improve overall maintainability.

I appreciate that you are working on hsr and want to improve its code
quality. I agree that there is quite some room for improvement here.
However, I have a few general remarks before commenting on the
individual patches:
- Please consider the netdev policy for simple clean-up patches outside
  the context of larger work [1] (esp. patches 5, 6).
- Please attribute the use of AI coding assistants [2].

Thanks,
   Felix


[1]: https://docs.kernel.org/process/maintainer-netdev.html#clean-up-patches
[2]: https://docs.kernel.org/process/coding-assistants.html

> Luka Gejak (7):
>   net: hsr: constify hsr_ops and prp_ops protocol operation structures
>   net: hsr: replace fallthrough comments with fallthrough macro
>   net: hsr: remove unnecessary void function return statement
>   net: hsr: use __func__ instead of hardcoded function name
>   net: hsr: remove unnecessary braces for single statement block
>   net: hsr: add missing blank lines after function declarations
>   net: hsr: use BIT() macro for bit shift constant

Re: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro

[Felix Maurer]

On Tue, Mar 24, 2026 at 03:46:25PM +0100, luka.gejak@linux.dev wrote:
> From: Luka Gejak <luka.gejak@linux.dev>
>
> Replace two instances of the legacy '/* Fall through */' comment with the
> standardized 'fallthrough;' macro in hsr_get_node_status() and
> hsr_get_node_list(). The kernel has standardized on the fallthrough macro
> since the migration from comment-based annotations, which provides
> compiler-level verification of intentional case fall-throughs.

As the test robot message suggests: the fallthrough macro is only for
case statement blocks.

> Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
> ---
>  net/hsr/hsr_netlink.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
> index db0b0af7a692..32c1b77cf84b 100644
> --- a/net/hsr/hsr_netlink.c
> +++ b/net/hsr/hsr_netlink.c
> @@ -433,7 +433,7 @@ static int hsr_get_node_status(struct sk_buff *skb_in, struct genl_info *info)
>
>  nla_put_failure:
>  	kfree_skb(skb_out);
> -	/* Fall through */
> +	fallthrough;
>
>  fail:
>  	rcu_read_unlock();
> @@ -524,7 +524,7 @@ static int hsr_get_node_list(struct sk_buff *skb_in, struct genl_info *info)
>
>  nla_put_failure:
>  	nlmsg_free(skb_out);
> -	/* Fall through */
> +	fallthrough;
>
>  fail:
>  	rcu_read_unlock();
> --
> 2.53.0
>

Re: [PATCH net-next v1 7/7] net: hsr: use BIT() macro for bit shift constant

[Felix Maurer]

On Tue, Mar 24, 2026 at 03:46:30PM +0100, luka.gejak@linux.dev wrote:
> From: Luka Gejak <luka.gejak@linux.dev>
>
> Replace the explicit bit shift (1 << HSR_SEQ_BLOCK_SHIFT) with the
> standardized BIT() macro for defining HSR_SEQ_BLOCK_SIZE. This improves
> readability and aligns with kernel coding conventions.

I know that checkpatch suggests this, but I don't agree with it:
HSR_SEQ_BLOCK_SHIFT is not a bitmap but a number, so in my opinion the
BIT() macro makes this particular define harder to read/understand.

> Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
> ---
>  net/hsr/hsr_framereg.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/hsr/hsr_framereg.h b/net/hsr/hsr_framereg.h
> index c65ecb925734..cb731ee0ce5c 100644
> --- a/net/hsr/hsr_framereg.h
> +++ b/net/hsr/hsr_framereg.h
> @@ -79,7 +79,7 @@ struct hsr_seq_block *hsr_get_seq_block(struct hsr_node *node, u16 block_idx);
>  #endif
>
>  #define HSR_SEQ_BLOCK_SHIFT 7 /* 128 bits */
> -#define HSR_SEQ_BLOCK_SIZE (1 << HSR_SEQ_BLOCK_SHIFT)
> +#define HSR_SEQ_BLOCK_SIZE BIT(HSR_SEQ_BLOCK_SHIFT)
>  #define HSR_SEQ_BLOCK_MASK (HSR_SEQ_BLOCK_SIZE - 1)
>  #define HSR_MAX_SEQ_BLOCKS 64
>
> --
> 2.53.0
>

Re: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro

[kernel test robot]

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/luka-gejak-linux-dev/net-hsr-constify-hsr_ops-and-prp_ops-protocol-operation-structures/20260326-143638
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260324144630.189094-3-luka.gejak%40linux.dev
patch subject: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro
config: parisc-randconfig-002-20260327 (https://download.01.org/0day-ci/archive/20260327/202603270549.2hiC5jsf-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260327/202603270549.2hiC5jsf-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603270549.2hiC5jsf-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/compiler_types.h:88,
                    from <command-line>:
   net/hsr/hsr_netlink.c: In function 'hsr_get_node_list':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
    # define fallthrough                    __attribute__((__fallthrough__))
                                            ^~~~~~~~~~~~~
   net/hsr/hsr_netlink.c:527:2: note: in expansion of macro 'fallthrough'
     fallthrough;
     ^~~~~~~~~~~
   net/hsr/hsr_netlink.c: In function 'hsr_get_node_status':
>> include/linux/compiler_attributes.h:214:41: error: invalid use of attribute 'fallthrough'
    # define fallthrough                    __attribute__((__fallthrough__))
                                            ^~~~~~~~~~~~~
   net/hsr/hsr_netlink.c:436:2: note: in expansion of macro 'fallthrough'
     fallthrough;
     ^~~~~~~~~~~


vim +/fallthrough +214 include/linux/compiler_attributes.h

294f69e662d157 Joe Perches   2019-10-05  201  
294f69e662d157 Joe Perches   2019-10-05  202  /*
294f69e662d157 Joe Perches   2019-10-05  203   * Add the pseudo keyword 'fallthrough' so case statement blocks
294f69e662d157 Joe Perches   2019-10-05  204   * must end with any of these keywords:
294f69e662d157 Joe Perches   2019-10-05  205   *   break;
294f69e662d157 Joe Perches   2019-10-05  206   *   fallthrough;
ca0760e7d79e2b Wei Ming Chen 2021-05-06  207   *   continue;
294f69e662d157 Joe Perches   2019-10-05  208   *   goto <label>;
294f69e662d157 Joe Perches   2019-10-05  209   *   return [expression];
294f69e662d157 Joe Perches   2019-10-05  210   *
294f69e662d157 Joe Perches   2019-10-05  211   *  gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes
294f69e662d157 Joe Perches   2019-10-05  212   */
294f69e662d157 Joe Perches   2019-10-05  213  #if __has_attribute(__fallthrough__)
294f69e662d157 Joe Perches   2019-10-05 @214  # define fallthrough                    __attribute__((__fallthrough__))
294f69e662d157 Joe Perches   2019-10-05  215  #else
294f69e662d157 Joe Perches   2019-10-05  216  # define fallthrough                    do {} while (0)  /* fallthrough */
a3f8a30f3f0079 Miguel Ojeda  2018-08-30  217  #endif
a3f8a30f3f0079 Miguel Ojeda  2018-08-30  218  

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Re: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro

[kernel test robot]

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/luka-gejak-linux-dev/net-hsr-constify-hsr_ops-and-prp_ops-protocol-operation-structures/20260326-143638
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260324144630.189094-3-luka.gejak%40linux.dev
patch subject: [PATCH net-next v1 2/7] net: hsr: replace fallthrough comments with fallthrough macro
config: i386-randconfig-001-20260327 (https://download.01.org/0day-ci/archive/20260327/202603270658.FJCTgZee-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260327/202603270658.FJCTgZee-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603270658.FJCTgZee-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/hsr/hsr_netlink.c:436:2: error: fallthrough annotation is outside switch statement
     436 |         fallthrough;
         |         ^
   include/linux/compiler_attributes.h:214:56: note: expanded from macro 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                                        ^
   net/hsr/hsr_netlink.c:527:2: error: fallthrough annotation is outside switch statement
     527 |         fallthrough;
         |         ^
   include/linux/compiler_attributes.h:214:56: note: expanded from macro 'fallthrough'
     214 | # define fallthrough                    __attribute__((__fallthrough__))
         |                                                        ^
   2 errors generated.


vim +436 net/hsr/hsr_netlink.c

   300	
   301	/* HSR_C_GET_NODE_STATUS lets userspace query the internal HSR node table
   302	 * about the status of a specific node in the network, defined by its MAC
   303	 * address.
   304	 *
   305	 * Input: hsr ifindex, node mac address
   306	 * Output: hsr ifindex, node mac address (copied from request),
   307	 *	   age of latest frame from node over slave 1, slave 2 [ms]
   308	 */
   309	static int hsr_get_node_status(struct sk_buff *skb_in, struct genl_info *info)
   310	{
   311		/* For receiving */
   312		struct nlattr *na;
   313		struct net_device *hsr_dev;
   314	
   315		/* For sending */
   316		struct sk_buff *skb_out;
   317		void *msg_head;
   318		struct hsr_priv *hsr;
   319		struct hsr_port *port;
   320		unsigned char hsr_node_addr_b[ETH_ALEN];
   321		int hsr_node_if1_age;
   322		u16 hsr_node_if1_seq;
   323		int hsr_node_if2_age;
   324		u16 hsr_node_if2_seq;
   325		int addr_b_ifindex;
   326		int res;
   327	
   328		if (!info)
   329			goto invalid;
   330	
   331		na = info->attrs[HSR_A_IFINDEX];
   332		if (!na)
   333			goto invalid;
   334		na = info->attrs[HSR_A_NODE_ADDR];
   335		if (!na)
   336			goto invalid;
   337	
   338		rcu_read_lock();
   339		hsr_dev = dev_get_by_index_rcu(genl_info_net(info),
   340					       nla_get_u32(info->attrs[HSR_A_IFINDEX]));
   341		if (!hsr_dev)
   342			goto rcu_unlock;
   343		if (!is_hsr_master(hsr_dev))
   344			goto rcu_unlock;
   345	
   346		/* Send reply */
   347		skb_out = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
   348		if (!skb_out) {
   349			res = -ENOMEM;
   350			goto fail;
   351		}
   352	
   353		msg_head = genlmsg_put(skb_out, NETLINK_CB(skb_in).portid,
   354				       info->snd_seq, &hsr_genl_family, 0,
   355				       HSR_C_SET_NODE_STATUS);
   356		if (!msg_head) {
   357			res = -ENOMEM;
   358			goto nla_put_failure;
   359		}
   360	
   361		res = nla_put_u32(skb_out, HSR_A_IFINDEX, hsr_dev->ifindex);
   362		if (res < 0)
   363			goto nla_put_failure;
   364	
   365		hsr = netdev_priv(hsr_dev);
   366		res = hsr_get_node_data(hsr,
   367					(unsigned char *)
   368					nla_data(info->attrs[HSR_A_NODE_ADDR]),
   369						 hsr_node_addr_b,
   370						 &addr_b_ifindex,
   371						 &hsr_node_if1_age,
   372						 &hsr_node_if1_seq,
   373						 &hsr_node_if2_age,
   374						 &hsr_node_if2_seq);
   375		if (res < 0)
   376			goto nla_put_failure;
   377	
   378		res = nla_put(skb_out, HSR_A_NODE_ADDR, ETH_ALEN,
   379			      nla_data(info->attrs[HSR_A_NODE_ADDR]));
   380		if (res < 0)
   381			goto nla_put_failure;
   382	
   383		if (addr_b_ifindex > -1) {
   384			res = nla_put(skb_out, HSR_A_NODE_ADDR_B, ETH_ALEN,
   385				      hsr_node_addr_b);
   386			if (res < 0)
   387				goto nla_put_failure;
   388	
   389			res = nla_put_u32(skb_out, HSR_A_ADDR_B_IFINDEX,
   390					  addr_b_ifindex);
   391			if (res < 0)
   392				goto nla_put_failure;
   393		}
   394	
   395		res = nla_put_u32(skb_out, HSR_A_IF1_AGE, hsr_node_if1_age);
   396		if (res < 0)
   397			goto nla_put_failure;
   398		res = nla_put_u16(skb_out, HSR_A_IF1_SEQ, hsr_node_if1_seq);
   399		if (res < 0)
   400			goto nla_put_failure;
   401		port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
   402		if (port)
   403			res = nla_put_u32(skb_out, HSR_A_IF1_IFINDEX,
   404					  port->dev->ifindex);
   405		if (res < 0)
   406			goto nla_put_failure;
   407	
   408		res = nla_put_u32(skb_out, HSR_A_IF2_AGE, hsr_node_if2_age);
   409		if (res < 0)
   410			goto nla_put_failure;
   411		res = nla_put_u16(skb_out, HSR_A_IF2_SEQ, hsr_node_if2_seq);
   412		if (res < 0)
   413			goto nla_put_failure;
   414		port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
   415		if (port)
   416			res = nla_put_u32(skb_out, HSR_A_IF2_IFINDEX,
   417					  port->dev->ifindex);
   418		if (res < 0)
   419			goto nla_put_failure;
   420	
   421		rcu_read_unlock();
   422	
   423		genlmsg_end(skb_out, msg_head);
   424		genlmsg_unicast(genl_info_net(info), skb_out, info->snd_portid);
   425	
   426		return 0;
   427	
   428	rcu_unlock:
   429		rcu_read_unlock();
   430	invalid:
   431		netlink_ack(skb_in, nlmsg_hdr(skb_in), -EINVAL, NULL);
   432		return 0;
   433	
   434	nla_put_failure:
   435		kfree_skb(skb_out);
 > 436		fallthrough;
   437	
   438	fail:
   439		rcu_read_unlock();
   440		return res;
   441	}
   442	

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