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| author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2021-10-12 14:40:40 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-10-12 17:35:18 -0700 |
| commit | deab6b1cd9789bb9bd466d5e76aecb8b336259b4 (patch) | |
| tree | fe4b45eb3ba2747af1991fb370ec5a79b49b0dc6 /net/dsa/Kconfig | |
| parent | ebb4c6a990f786d7e0e4618a0d3766cd660125d8 (diff) | |
| download | lwn-deab6b1cd9789bb9bd466d5e76aecb8b336259b4.tar.gz lwn-deab6b1cd9789bb9bd466d5e76aecb8b336259b4.zip | |
net: dsa: tag_ocelot: break circular dependency with ocelot switch lib driver
As explained here:
https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/
DSA tagging protocol drivers cannot depend on symbols exported by switch
drivers, because this creates a circular dependency that breaks module
autoloading.
The tag_ocelot.c file depends on the ocelot_ptp_rew_op() function
exported by the common ocelot switch lib. This function looks at
OCELOT_SKB_CB(skb) and computes how to populate the REW_OP field of the
DSA tag, for PTP timestamping (the command: one-step/two-step, and the
TX timestamp identifier).
None of that requires deep insight into the driver, it is quite
stateless, as it only depends upon the skb->cb. So let's make it a
static inline function and put it in include/linux/dsa/ocelot.h, a
file that despite its name is used by the ocelot switch driver for
populating the injection header too - since commit 40d3f295b5fe ("net:
mscc: ocelot: use common tag parsing code with DSA").
With that function declared as static inline, its body is expanded
inside each call site, so the dependency is broken and the DSA tagger
can be built without the switch library, upon which the felix driver
depends.
Fixes: 39e5308b3250 ("net: mscc: ocelot: support PTP Sync one-step timestamping")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/dsa/Kconfig')
| -rw-r--r-- | net/dsa/Kconfig | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig index bca1b5d66df2..d166377d7085 100644 --- a/net/dsa/Kconfig +++ b/net/dsa/Kconfig @@ -101,8 +101,6 @@ config NET_DSA_TAG_RTL4_A config NET_DSA_TAG_OCELOT tristate "Tag driver for Ocelot family of switches, using NPI port" - depends on MSCC_OCELOT_SWITCH_LIB || \ - (MSCC_OCELOT_SWITCH_LIB=n && COMPILE_TEST) select PACKING help Say Y or M if you want to enable NPI tagging for the Ocelot switches |