On Fri, Nov 22, 2024 at 4:57 AM Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote:
>
> The usage of the macro allows to remove the custom handler function,
> saving some memory. Additionally the code is easier to read.
>
> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> ---
> Something similar can be done to btf_module_read() in kernel/bpf/btf.c.
> But doing it here and now would lead to some conflicts with some other
> sysfs refactorings I'm doing. It will be part of a future series.
> ---
> kernel/bpf/sysfs_btf.c | 21 +++++----------------
> 1 file changed, 5 insertions(+), 16 deletions(-)
>
Nice, let's simplify. But why change the name to generic "vmlinux" if
it's actually btf_vmlinux? Can we keep the original btf-specific name?
pw-bot: cr
> diff --git a/kernel/bpf/sysfs_btf.c b/kernel/bpf/sysfs_btf.c
> index fedb54c94cdb830a4890d33677dcc5a6e236c13f..a24381f933d0b80b11116d05463c35e9fa66acb1 100644
> --- a/kernel/bpf/sysfs_btf.c
> +++ b/kernel/bpf/sysfs_btf.c
> @@ -12,34 +12,23 @@
> extern char __start_BTF[];
> extern char __stop_BTF[];
>
> -static ssize_t
> -btf_vmlinux_read(struct file *file, struct kobject *kobj,
> - struct bin_attribute *bin_attr,
> - char *buf, loff_t off, size_t len)
> -{
> - memcpy(buf, __start_BTF + off, len);
> - return len;
> -}
> -
> -static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
> - .attr = { .name = "vmlinux", .mode = 0444, },
> - .read = btf_vmlinux_read,
> -};
> +static __ro_after_init BIN_ATTR_SIMPLE_RO(vmlinux);
>
> struct kobject *btf_kobj;
>
> static int __init btf_vmlinux_init(void)
> {
> - bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF;
> + bin_attr_vmlinux.private = __start_BTF;
> + bin_attr_vmlinux.size = __stop_BTF - __start_BTF;
>
> - if (bin_attr_btf_vmlinux.size == 0)
> + if (bin_attr_vmlinux.size == 0)
> return 0;
>
> btf_kobj = kobject_create_and_add("btf", kernel_kobj);
> if (!btf_kobj)
> return -ENOMEM;
>
> - return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
> + return sysfs_create_bin_file(btf_kobj, &bin_attr_vmlinux);
> }
>
> subsys_initcall(btf_vmlinux_init);
>
> ---
> base-commit: 28eb75e178d389d325f1666e422bc13bbbb9804c
> change-id: 20241122-sysfs-const-bin_attr-bpf-737286bb9f27
>
> Best regards,
> --
> Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
>
