From: Leah Rumancik <leah.rumancik@gmail.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: bpf@vger.kernel.org, linux-block@vger.kernel.org,
orbekk@google.com, harshads@google.com, jasiu@google.com,
saranyamohan@google.com, tytso@google.com, bvanassche@google.com
Subject: Re: [RFC PATCH 1/4] bpf: add new prog_type BPF_PROG_TYPE_IO_FILTER
Date: Fri, 4 Sep 2020 11:43:10 -0400 [thread overview]
Message-ID: <20200904154309.GA2048@leah-Ubuntu> (raw)
In-Reply-To: <20200813230021.llbkj5ihyadcbuia@kafai-mbp.dhcp.thefacebook.com>
On Thu, Aug 13, 2020 at 04:00:51PM -0700, Martin KaFai Lau wrote:
> On Wed, Aug 12, 2020 at 04:33:02PM +0000, 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.
>
> [ ... ]
>
> > +#define BPF_MAX_PROGS 64
> > +
> > +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);
> > + 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;
> > +}
> bpf link should be used.
> netns_bpf_link_create() can be used as an example.
I'll update this, thanks for the example.
> > diff --git a/include/uapi/linux/bpf.h Vb/include/uapi/linux/bpf.h
> > +struct bpf_io_request {
> > + __u64 sector_start; /* first sector */
> > + __u32 sector_cnt; /* number of sectors */
> > + __u32 opf; /* bio->bi_opf */
> > +};
> Is it all that are needed from "struct bio" to do the filtering and monitoring?
> Please elaborate a few more specific filtering usecases in the comment
> or even better is to add those usecases to the tests.
Fields can be added to the bpf_io_request later if needed. I'll add some
more tests and clarification in comments in the next version.
>
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index 94cead5a43e5..71372e99a722 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -2613,6 +2613,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
> > case BPF_PROG_TYPE_LWT_SEG6LOCAL:
> > case BPF_PROG_TYPE_SK_REUSEPORT:
> > case BPF_PROG_TYPE_FLOW_DISSECTOR:
> > + case BPF_PROG_TYPE_IO_FILTER:
> Why it is needed?
Does not look like this is needed. I will remove it.
Thanks for the review,
Leah
next prev parent reply other threads:[~2020-09-04 15:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-12 16:33 [RFC PATCH 0/4] block/bpf: add eBPF based block layer IO filtering Leah Rumancik
2020-08-12 16:33 ` [RFC PATCH 1/4] bpf: add new prog_type BPF_PROG_TYPE_IO_FILTER Leah Rumancik
2020-08-13 23:00 ` Martin KaFai Lau
2020-09-04 15:43 ` Leah Rumancik [this message]
2020-08-17 14:18 ` Bob Liu
2020-08-17 16:32 ` Alexei Starovoitov
2020-09-04 16:46 ` Leah Rumancik
2020-09-04 18:50 ` Alexei Starovoitov
2020-09-17 18:33 ` Leah Rumancik
2020-09-01 16:53 ` Leah Rumancik
2020-09-02 7:36 ` Bob Liu
2020-08-18 12:53 ` Jakub Sitnicki
2020-09-04 17:29 ` Leah Rumancik
2020-08-12 16:33 ` [RFC PATCH 2/4] bpf: add protect_gpt sample program Leah Rumancik
2020-08-13 22:58 ` Martin KaFai Lau
2020-09-01 16:33 ` Leah Rumancik
2020-08-12 16:33 ` [RFC PATCH 3/4] bpf: add eBPF IO filter documentation Leah Rumancik
2020-08-12 17:04 ` Bart Van Assche
2020-08-12 17:50 ` Jonathan Corbet
2020-09-01 15:35 ` Leah Rumancik
2020-08-12 16:33 ` [RFC PATCH 4/4] bpf: add BPF_PROG_TYPE_LSM to bpftool name array Leah Rumancik
2020-08-12 17:00 ` Bart Van Assche
2020-08-12 18:17 ` Tobias Klauser
2020-09-01 15:18 ` Leah Rumancik
2020-08-17 6:37 ` [RFC PATCH 0/4] block/bpf: add eBPF based block layer IO filtering Christoph Hellwig
2020-08-18 2:44 ` Ming Lei
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