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Subject[PATCH 5.4 151/191] net, sysctl: Fix compiler warning when only cBPF is present
Date
From: Alexander Lobakin <alobakin@dlink.ru>

commit 1148f9adbe71415836a18a36c1b4ece999ab0973 upstream.

proc_dointvec_minmax_bpf_restricted() has been firstly introduced
in commit 2e4a30983b0f ("bpf: restrict access to core bpf sysctls")
under CONFIG_HAVE_EBPF_JIT. Then, this ifdef has been removed in
ede95a63b5e8 ("bpf: add bpf_jit_limit knob to restrict unpriv
allocations"), because a new sysctl, bpf_jit_limit, made use of it.
Finally, this parameter has become long instead of integer with
fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
and thus, a new proc_dolongvec_minmax_bpf_restricted() has been
added.

With this last change, we got back to that
proc_dointvec_minmax_bpf_restricted() is used only under
CONFIG_HAVE_EBPF_JIT, but the corresponding ifdef has not been
brought back.

So, in configurations like CONFIG_BPF_JIT=y && CONFIG_HAVE_EBPF_JIT=n
since v4.20 we have:

CC net/core/sysctl_net_core.o
net/core/sysctl_net_core.c:292:1: warning: ‘proc_dointvec_minmax_bpf_restricted’ defined but not used [-Wunused-function]
292 | proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Suppress this by guarding it with CONFIG_HAVE_EBPF_JIT again.

Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191218091821.7080-1-alobakin@dlink.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/core/sysctl_net_core.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -288,6 +288,7 @@ static int proc_dointvec_minmax_bpf_enab
return ret;
}

+# ifdef CONFIG_HAVE_EBPF_JIT
static int
proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
@@ -298,6 +299,7 @@ proc_dointvec_minmax_bpf_restricted(stru

return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
}
+# endif /* CONFIG_HAVE_EBPF_JIT */

static int
proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,

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