2022-05-14 02:10:49

by Vincent MAILHOL

[permalink] [raw]
Subject: [PATCH v2 1/2] can: skb:: move can_dropped_invalid_skb and can_skb_headroom_valid to skb.c

The functions can_dropped_invalid_skb() and can_skb_headroom_valid()
grew a lot over the years to a point which it does make much sense to
have them defined as static inline in header files. Move those two
functions to the .c counterpart of skb.h.

can_skb_headroom_valid() only caller being can_dropped_invalid_skb(),
the declaration is removed from the header. Only
can_dropped_invalid_skb() gets its symbol exported.

While doing so, do a small cleanup: add brackets around the else block
in can_dropped_invalid_skb().

Signed-off-by: Vincent Mailhol <[email protected]>
---
drivers/net/can/dev/skb.c | 58 ++++++++++++++++++++++++++++++++++++++
include/linux/can/skb.h | 59 +--------------------------------------
2 files changed, 59 insertions(+), 58 deletions(-)

diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index 61660248c69e..8b1991130de5 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c
@@ -252,3 +252,61 @@ struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_err_skb);
+
+/* Check for outgoing skbs that have not been created by the CAN subsystem */
+static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
+{
+ /* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
+ if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
+ return false;
+
+ /* af_packet does not apply CAN skb specific settings */
+ if (skb->ip_summed == CHECKSUM_NONE) {
+ /* init headroom */
+ can_skb_prv(skb)->ifindex = dev->ifindex;
+ can_skb_prv(skb)->skbcnt = 0;
+
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ /* perform proper loopback on capable devices */
+ if (dev->flags & IFF_ECHO)
+ skb->pkt_type = PACKET_LOOPBACK;
+ else
+ skb->pkt_type = PACKET_HOST;
+
+ skb_reset_mac_header(skb);
+ skb_reset_network_header(skb);
+ skb_reset_transport_header(skb);
+ }
+
+ return true;
+}
+
+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
+{
+ const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
+ if (skb->protocol == htons(ETH_P_CAN)) {
+ if (unlikely(skb->len != CAN_MTU ||
+ cfd->len > CAN_MAX_DLEN))
+ goto inval_skb;
+ } else if (skb->protocol == htons(ETH_P_CANFD)) {
+ if (unlikely(skb->len != CANFD_MTU ||
+ cfd->len > CANFD_MAX_DLEN))
+ goto inval_skb;
+ } else {
+ goto inval_skb;
+ }
+
+ if (!can_skb_headroom_valid(dev, skb))
+ goto inval_skb;
+
+ return false;
+
+inval_skb:
+ kfree_skb(skb);
+ dev->stats.tx_dropped++;
+ return true;
+}
+EXPORT_SYMBOL_GPL(can_dropped_invalid_skb);
diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index fdb22b00674a..182749e858b3 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -31,6 +31,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev,
struct canfd_frame **cfd);
struct sk_buff *alloc_can_err_skb(struct net_device *dev,
struct can_frame **cf);
+bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb);

/*
* The struct can_skb_priv is used to transport additional information along
@@ -96,64 +97,6 @@ static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
return nskb;
}

-/* Check for outgoing skbs that have not been created by the CAN subsystem */
-static inline bool can_skb_headroom_valid(struct net_device *dev,
- struct sk_buff *skb)
-{
- /* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
- if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
- return false;
-
- /* af_packet does not apply CAN skb specific settings */
- if (skb->ip_summed == CHECKSUM_NONE) {
- /* init headroom */
- can_skb_prv(skb)->ifindex = dev->ifindex;
- can_skb_prv(skb)->skbcnt = 0;
-
- skb->ip_summed = CHECKSUM_UNNECESSARY;
-
- /* perform proper loopback on capable devices */
- if (dev->flags & IFF_ECHO)
- skb->pkt_type = PACKET_LOOPBACK;
- else
- skb->pkt_type = PACKET_HOST;
-
- skb_reset_mac_header(skb);
- skb_reset_network_header(skb);
- skb_reset_transport_header(skb);
- }
-
- return true;
-}
-
-/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
-static inline bool can_dropped_invalid_skb(struct net_device *dev,
- struct sk_buff *skb)
-{
- const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
-
- if (skb->protocol == htons(ETH_P_CAN)) {
- if (unlikely(skb->len != CAN_MTU ||
- cfd->len > CAN_MAX_DLEN))
- goto inval_skb;
- } else if (skb->protocol == htons(ETH_P_CANFD)) {
- if (unlikely(skb->len != CANFD_MTU ||
- cfd->len > CANFD_MAX_DLEN))
- goto inval_skb;
- } else
- goto inval_skb;
-
- if (!can_skb_headroom_valid(dev, skb))
- goto inval_skb;
-
- return false;
-
-inval_skb:
- kfree_skb(skb);
- dev->stats.tx_dropped++;
- return true;
-}
-
static inline bool can_is_canfd_skb(const struct sk_buff *skb)
{
/* the CAN specific type of skb is identified by its data length */
--
2.35.1



2022-05-14 05:33:16

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] can: skb:: move can_dropped_invalid_skb and can_skb_headroom_valid to skb.c

Hi Vincent,

I love your patch! Yet something to improve:

[auto build test ERROR on mkl-can-next/testing]
[also build test ERROR on v5.18-rc6 next-20220513]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url: https://github.com/intel-lab-lkp/linux/commits/Vincent-Mailhol/can-skb-move-can_dropped_invalid_skb-and-can_skb_headroom_valid-to-skb-c/20220514-003707
base: https://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git testing
config: arm-randconfig-r021-20220512 (https://download.01.org/0day-ci/archive/20220514/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 38189438b69ca27b4c6ce707c52dbd217583d046)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/intel-lab-lkp/linux/commit/8f56e6b1b9945ea47c9f410d1254451df9d6fe22
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Vincent-Mailhol/can-skb-move-can_dropped_invalid_skb-and-can_skb_headroom_valid-to-skb-c/20220514-003707
git checkout 8f56e6b1b9945ea47c9f410d1254451df9d6fe22
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>

All errors (new ones prefixed by >>):

ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected
ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected
>> ld.lld: error: undefined symbol: can_dropped_invalid_skb
>>> referenced by vxcan.c:45 (drivers/net/can/vxcan.c:45)
>>> net/can/vxcan.o:(vxcan_xmit) in archive drivers/built-in.a

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-05-14 06:23:46

by Vincent MAILHOL

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] can: skb:: move can_dropped_invalid_skb and can_skb_headroom_valid to skb.c

On Sat. 14 May 2022 à 13:20, kernel test robot <[email protected]> wrote:
> Hi Vincent,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on mkl-can-next/testing]
> [also build test ERROR on v5.18-rc6 next-20220513]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Vincent-Mailhol/can-skb-move-can_dropped_invalid_skb-and-can_skb_headroom_valid-to-skb-c/20220514-003707
> base: https://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git testing
> config: arm-randconfig-r021-20220512 (https://download.01.org/0day-ci/archive/20220514/[email protected]/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 38189438b69ca27b4c6ce707c52dbd217583d046)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # install arm cross compiling tool for clang build
> # apt-get install binutils-arm-linux-gnueabi
> # https://github.com/intel-lab-lkp/linux/commit/8f56e6b1b9945ea47c9f410d1254451df9d6fe22
> git remote add linux-review https://github.com/intel-lab-lkp/linux
> git fetch --no-tags linux-review Vincent-Mailhol/can-skb-move-can_dropped_invalid_skb-and-can_skb_headroom_valid-to-skb-c/20220514-003707
> git checkout 8f56e6b1b9945ea47c9f410d1254451df9d6fe22
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>):
>
> ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected
> ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected
> >> ld.lld: error: undefined symbol: can_dropped_invalid_skb
> >>> referenced by vxcan.c:45 (drivers/net/can/vxcan.c:45)
> >>> net/can/vxcan.o:(vxcan_xmit) in archive drivers/built-in.a

OK, so the issue is that VCAN and VXCAN are users of
can_dropped_invalid_skb() but do not depend on CAN_DEV. Above error
will appear if CONFIG_CAN_DEV is not set (or if CONFIG_V{,X}CAN is set
to "yes" and CAN_DEV is set to "module").
I see three choices here:
1. move can_dropped_invalid_skb() outside of drivers/net/can (i.e.
move it somewhere in net/can).
2. split CAN_DEV into one additional sub module: CAN_SKB and add a
dependency to it in VCAN and VXCAN.
3. Add a dependency to CAN_DEV in VCAN and VXCAN

1. is I think the worse, 2. the best, 3. is the laziest option and is
kind of acceptable.
@Marc (and anyone else), what are your thoughts?

Yours sincerely,
Vincent Mailhol

2022-05-14 16:34:46

by Max Staudt

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] can: skb:: move can_dropped_invalid_skb and can_skb_headroom_valid to skb.c

On Sat, 14 May 2022 14:16:09 +0900
Vincent MAILHOL <[email protected]> wrote:

> OK, so the issue is that VCAN and VXCAN are users of
> can_dropped_invalid_skb() but do not depend on CAN_DEV. Above error
> will appear if CONFIG_CAN_DEV is not set (or if CONFIG_V{,X}CAN is set
> to "yes" and CAN_DEV is set to "module").
> I see three choices here:
> 1. move can_dropped_invalid_skb() outside of drivers/net/can (i.e.
> move it somewhere in net/can).
> 2. split CAN_DEV into one additional sub module: CAN_SKB and add a
> dependency to it in VCAN and VXCAN.
> 3. Add a dependency to CAN_DEV in VCAN and VXCAN
>
> 1. is I think the worse, 2. the best, 3. is the laziest option and is
> kind of acceptable.
> @Marc (and anyone else), what are your thoughts?

I think that having v(x)can depend on can-dev isn't half bad - for the
user, they are CAN devices, anyway, and modprobe does the dependency
resolution magic.

Splitting into too many modules is something I'd avoid because of the
overhead involved.



Max