net: dsa: sja1105: fix -ENOSPC when replacing the same tc-cbs too many times

stable inclusion
from stable-v5.10.195
commit e89a361d99f63b61fd5097c868d27a18ff3dff27
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I95JOC

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e89a361d99f63b61fd5097c868d27a18ff3dff27



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[ Upstream commit 894cafc5 ]

After running command [2] too many times in a row:

[1] $ tc qdisc add dev sw2p0 root handle 1: mqprio num_tc 8 \
	map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
[2] $ tc qdisc replace dev sw2p0 parent 1:1 cbs offload 1 \
	idleslope 120000 sendslope -880000 locredit -1320 hicredit 180

(aka more than priv->info->num_cbs_shapers times)

we start seeing the following error message:

Error: Specified device failed to setup cbs hardware offload.

This comes from the fact that ndo_setup_tc(TC_SETUP_QDISC_CBS) presents
the same API for the qdisc create and replace cases, and the sja1105
driver fails to distinguish between the 2. Thus, it always thinks that
it must allocate the same shaper for a {port, queue} pair, when it may
instead have to replace an existing one.

Fixes: 4d752508 ("net: dsa: sja1105: offload the Credit-Based Shaper qdisc")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>