On Wed, Aug 12, 2020 at 06:33 PM CEST, Leah Rumancik wrote:
> Introducing a new program type BPF_PROG_TYPE_IO_FILTER and a new
> attach type BPF_BIO_SUBMIT.
>
> This program type is intended to help filter and monitor IO requests.
>
> Co-developed-by: Saranya Muruganandam <saranyamohan@xxxxxxxxxx>
> Signed-off-by: Saranya Muruganandam <saranyamohan@xxxxxxxxxx>
> Signed-off-by: Kjetil Ørbekk <orbekk@xxxxxxxxxx>
> Signed-off-by: Harshad Shirwadkar <harshads@xxxxxxxxxx>
> Signed-off-by: Leah Rumancik <leah.rumancik@xxxxxxxxx>
> ---
[...]
> diff --git a/block/blk-bpf-io-filter.c b/block/blk-bpf-io-filter.c
> new file mode 100644
> index 000000000000..453d6b156bd2
> --- /dev/null
> +++ b/block/blk-bpf-io-filter.c
[...]
> +int io_filter_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
> +{
> + struct gendisk *disk;
> + struct fd f;
> + struct bpf_prog_array *old_array;
> + struct bpf_prog_array *new_array;
> + int ret;
> +
> + if (attr->attach_flags)
> + return -EINVAL;
> +
> + f = fdget(attr->target_fd);
^^^^^
Missing corresponding fdput?
As per Martin's suggestion, with bpf_link this will become the
link_create callback, but the comment still stands.
> + if (!f.file)
> + return -EBADF;
> +
> + disk = I_BDEV(f.file->f_mapping->host)->bd_disk;
> + if (disk == NULL)
> + return -ENXIO;
> +
> + ret = mutex_lock_interruptible(&disk->io_filter_lock);
> + if (ret)
> + return ret;
> +
> + old_array = io_filter_rcu_dereference_progs(disk);
> + if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) {
> + ret = -E2BIG;
> + goto unlock;
> + }
> +
> + ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
> + if (ret < 0)
> + goto unlock;
> +
> + rcu_assign_pointer(disk->progs, new_array);
> + bpf_prog_array_free(old_array);
> +
> +unlock:
> + mutex_unlock(&disk->io_filter_lock);
> + return ret;
> +}
[...]
