We run into an exhaustion problem with the kernel-allocated filter IDs.
Our allocation problem can be fixed on the user space side,
but the error message in this case was quite misleading:
"Filter with specified priority/protocol not found" (EINVAL)
Specifically when we can't allocate a _new_ ID because filter with
lowest ID already _exists_, saying "filter not found", is confusing.
Kernel allocates IDs in range of 0xc0000 -> 0x8000, giving out ID one
lower than lowest existing in that range. The error message makes sense
when tcf_chain_tp_find() gets called for GET and DEL but for NEW we
need to provide more specific error messages for all three cases:
- user wants the ID to be auto-allocated but filter with ID 0x8000
already exists
- filter already exists and can be replaced, but user asked
for a protocol change
- filter doesn't exist
Caller of tcf_chain_tp_insert_unique() doesn't set extack today,
so don't bother plumbing it in.
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20241108010254.2995438-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
a58f00ed24