linux/net/dsa
Vladimir Oltean e1eea81120 net: dsa: introduce a dsa_port_from_netdev public helper
As its implementation shows, this is synonimous with calling
dsa_slave_dev_check followed by dsa_slave_to_port, so it is quite simple
already and provides functionality which is already there.

However there is now a need for these functions outside dsa_priv.h, for
example in drivers that perform mirroring and redirection through
tc-flower offloads (they are given raw access to the flow_cls_offload
structure), where they need to call this function on act->dev.

But simply exporting dsa_slave_to_port would make it non-inline and
would result in an extra function call in the hotpath, as can be seen
for example in sja1105:

Before:

000006dc <sja1105_xmit>:
{
 6dc:	e92d4ff0 	push	{r4, r5, r6, r7, r8, r9, sl, fp, lr}
 6e0:	e1a04000 	mov	r4, r0
 6e4:	e591958c 	ldr	r9, [r1, #1420]	; 0x58c <- Inline dsa_slave_to_port
 6e8:	e1a05001 	mov	r5, r1
 6ec:	e24dd004 	sub	sp, sp, #4
	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 6f0:	e1c901d8 	ldrd	r0, [r9, #24]
 6f4:	ebfffffe 	bl	0 <dsa_8021q_tx_vid>
			6f4: R_ARM_CALL	dsa_8021q_tx_vid
	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
 6f8:	e1d416b0 	ldrh	r1, [r4, #96]	; 0x60
	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 6fc:	e1a08000 	mov	r8, r0

After:

000006e4 <sja1105_xmit>:
{
 6e4:	e92d4ff0 	push	{r4, r5, r6, r7, r8, r9, sl, fp, lr}
 6e8:	e1a04000 	mov	r4, r0
 6ec:	e24dd004 	sub	sp, sp, #4
	struct dsa_port *dp = dsa_slave_to_port(netdev);
 6f0:	e1a00001 	mov	r0, r1
{
 6f4:	e1a05001 	mov	r5, r1
	struct dsa_port *dp = dsa_slave_to_port(netdev);
 6f8:	ebfffffe 	bl	0 <dsa_slave_to_port>
			6f8: R_ARM_CALL	dsa_slave_to_port
 6fc:	e1a09000 	mov	r9, r0
	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 700:	e1c001d8 	ldrd	r0, [r0, #24]
 704:	ebfffffe 	bl	0 <dsa_8021q_tx_vid>
			704: R_ARM_CALL	dsa_8021q_tx_vid

Because we want to avoid possible performance regressions, introduce
this new function which is designed to be public.

Suggested-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-07 17:31:57 -07:00
..
dsa2.c net: dsa: Do not make user port errors fatal 2020-05-04 10:29:47 -07:00
dsa_priv.h net: dsa: add GRO support via gro_cells 2020-04-23 12:32:13 -07:00
dsa.c net: dsa: introduce a dsa_port_from_netdev public helper 2020-05-07 17:31:57 -07:00
Kconfig net: dsa: add GRO support via gro_cells 2020-04-23 12:32:13 -07:00
Makefile net: dsa: add support for Atheros AR9331 TAG format 2019-12-20 17:05:47 -08:00
master.c net: dsa: Do not leave DSA master with NULL netdev_ops 2020-05-06 17:31:54 -07:00
port.c net: dsa: Down cpu/dsa ports phylink will control 2020-04-14 16:33:26 -07:00
slave.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 22:10:13 -07:00
switch.c net: dsa: configure the MTU for switch ports 2020-03-27 16:07:24 -07:00
tag_8021q.c net: dsa: tag_8021q: replace dsa_8021q_remove_header with __skb_vlan_pop 2020-03-24 16:19:01 -07:00
tag_ar9331.c net: dsa: tag_ar9331: Make sure there is headroom for tag 2020-02-14 07:34:51 -08:00
tag_brcm.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-25 18:58:11 -07:00
tag_dsa.c dsa: Cleanup unneeded table and make tag structures static 2019-04-28 19:41:01 -04:00
tag_edsa.c dsa: Cleanup unneeded table and make tag structures static 2019-04-28 19:41:01 -04:00
tag_gswip.c net: dsa: tag_gswip: fix typo in tagger name 2020-01-16 13:58:26 +01:00
tag_ksz.c net: dsa: ksz: use common define for tag len 2019-12-20 21:06:49 -08:00
tag_lan9303.c dsa: Cleanup unneeded table and make tag structures static 2019-04-28 19:41:01 -04:00
tag_mtk.c dsa: Cleanup unneeded table and make tag structures static 2019-04-28 19:41:01 -04:00
tag_ocelot.c net: mscc: ocelot: eliminate confusion between CPU and NPI port 2020-03-04 14:19:00 -08:00
tag_qca.c net: dsa: tag_qca: Make sure there is headroom for tag 2020-02-14 07:34:51 -08:00
tag_sja1105.c net: dsa: tag_8021q: replace dsa_8021q_remove_header with __skb_vlan_pop 2020-03-24 16:19:01 -07:00
tag_trailer.c dsa: Cleanup unneeded table and make tag structures static 2019-04-28 19:41:01 -04:00