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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240823_190407_977774_CA3A5F95 X-CRM114-Status: GOOD ( 20.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 08/22, Alexei Starovoitov wrote: > On Thu, Aug 22, 2024 at 12:02 AM Tze-nan Wu (吳澤南) > wrote: > > > > > > BTW, If this should be handled in kernel, modification shown below > > could fix the issue without breaking the "static_branch" usage in both > > macros: > > > > > > +++ /include/linux/bpf-cgroup.h: > > -#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen) > > +#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen, compat) > > ({ > > int __ret = 0; > > if (cgroup_bpf_enabled(CGROUP_GETSOCKOPT)) > > copy_from_sockptr(&__ret, optlen, sizeof(int)); > > + else > > + *compat = true; > > __ret; > > }) > > > > #define BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock, level, optname, > > optval, optlen, max_optlen, retval) > > ({ > > int __ret = retval; > > - if (cgroup_bpf_enabled(CGROUP_GETSOCKOPT) && > > - cgroup_bpf_sock_enabled(sock, CGROUP_GETSOCKOPT)) > > + if (cgroup_bpf_sock_enabled(sock, CGROUP_GETSOCKOPT)) > > if (!(sock)->sk_prot->bpf_bypass_getsockopt || > > ... > > > > +++ /net/socket.c: > > int do_sock_getsockopt(struct socket *sock, bool compat, int level, > > { > > ... > > ... > > + /* The meaning of `compat` variable could be changed here > > + * to indicate if cgroup_bpf_enabled(CGROUP_SOCK_OPS) is > > false. > > + */ > > if (!compat) > > - max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen); > > + max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen, > > &compat); > > This is better, but it's still quite a hack. Let's not override it. > We can have another bool, but the question: > do we really need BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN ? > copy_from_sockptr(&__ret, optlen, sizeof(int)); > should be fast enough to do it unconditionally. > What are we saving here? > > Stan ? Agreed, most likely nobody would notice :-)