diff mbox series

[v4,bpf-next,09/13] bpf: introduce multibuff support to bpf_prog_test_run_xdp()

Message ID d6ed575afaf89fc35e233af5ccd063da944b4a3a.1601648734.git.lorenzo@kernel.org
State New
Headers show
Series mvneta: introduce XDP multi-buffer support | expand

Commit Message

Lorenzo Bianconi Oct. 2, 2020, 2:42 p.m. UTC
Introduce the capability to allocate a xdp multi-buff in
bpf_prog_test_run_xdp routine. This is a preliminary patch to introduce
the selftests for new xdp multi-buff ebpf helpers

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 net/bpf/test_run.c | 51 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 43 insertions(+), 8 deletions(-)

Comments

Shay Agroskin Oct. 8, 2020, 8:06 a.m. UTC | #1
Lorenzo Bianconi <lorenzo@kernel.org> writes:

> Introduce the capability to allocate a xdp multi-buff in

> bpf_prog_test_run_xdp routine. This is a preliminary patch to 

> introduce

> the selftests for new xdp multi-buff ebpf helpers

>

> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

> ---

>  net/bpf/test_run.c | 51 

>  ++++++++++++++++++++++++++++++++++++++--------

>  1 file changed, 43 insertions(+), 8 deletions(-)

>

> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c

> index bd291f5f539c..ec7286cd051b 100644

> --- a/net/bpf/test_run.c

> +++ b/net/bpf/test_run.c

> @@ -617,44 +617,79 @@ int bpf_prog_test_run_xdp(struct bpf_prog 

> *prog, const union bpf_attr *kattr,

>  {

>  	u32 tailroom = SKB_DATA_ALIGN(sizeof(struct 

>  skb_shared_info));

>  	u32 headroom = XDP_PACKET_HEADROOM;

> -	u32 size = kattr->test.data_size_in;

>  	u32 repeat = kattr->test.repeat;

>  	struct netdev_rx_queue *rxqueue;

> +	struct skb_shared_info *sinfo;

>  	struct xdp_buff xdp = {};

> +	u32 max_data_sz, size;

>  	u32 retval, duration;

> -	u32 max_data_sz;

> +	int i, ret, data_len;

>  	void *data;

> -	int ret;

>  

>  	if (kattr->test.ctx_in || kattr->test.ctx_out)

>  		return -EINVAL;

>  

> -	/* XDP have extra tailroom as (most) drivers use full page 

> */

>  	max_data_sz = 4096 - headroom - tailroom;


For the sake of consistency, can this 4096 be changed to PAGE_SIZE 
?
Same as in
     data_len = min_t(int, kattr->test.data_size_in - size, 
     PAGE_SIZE);

expression below

> +	size = min_t(u32, kattr->test.data_size_in, max_data_sz);

> +	data_len = size;

>  

> -	data = bpf_test_init(kattr, kattr->test.data_size_in,

> -			     max_data_sz, headroom, tailroom);

> +	data = bpf_test_init(kattr, size, max_data_sz, headroom, 

> tailroom);

>  	if (IS_ERR(data))

>  		return PTR_ERR(data);

>  

>  	xdp.data_hard_start = data;

>  	xdp.data = data + headroom;

>  	xdp.data_meta = xdp.data;

> -	xdp.data_end = xdp.data + size;

> +	xdp.data_end = xdp.data + data_len;

>  	xdp.frame_sz = headroom + max_data_sz + tailroom;

>  

> +	sinfo = xdp_get_shared_info_from_buff(&xdp);

> +	if (unlikely(kattr->test.data_size_in > size)) {

> +		void __user *data_in = 

> u64_to_user_ptr(kattr->test.data_in);

> +

> +		while (size < kattr->test.data_size_in) {

> +			skb_frag_t *frag = 

> &sinfo->frags[sinfo->nr_frags];

> +			struct page *page;

> +			int data_len;

> +

> +			page = alloc_page(GFP_KERNEL);

> +			if (!page) {

> +				ret = -ENOMEM;

> +				goto out;

> +			}

> +

> +			__skb_frag_set_page(frag, page);

> +			data_len = min_t(int, 

> kattr->test.data_size_in - size,

> +					 PAGE_SIZE);

> +			skb_frag_size_set(frag, data_len);

> +			if (copy_from_user(page_address(page), 

> data_in + size,

> +					   data_len)) {

> +				ret = -EFAULT;

> +				goto out;

> +			}

> +			sinfo->nr_frags++;

> +			size += data_len;

> +		}

> +		xdp.mb = 1;

> +	}

> +

>  	rxqueue = 

>  __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 

>  0);

>  	xdp.rxq = &rxqueue->xdp_rxq;

>  	bpf_prog_change_xdp(NULL, prog);

>  	ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration, 

>  true);

>  	if (ret)

>  		goto out;

> +

>  	if (xdp.data != data + headroom || xdp.data_end != 

>  xdp.data + size)

> -		size = xdp.data_end - xdp.data;

> +		size += xdp.data_end - xdp.data - data_len;


Can we please drop the variable shadowing of data_len ? This is 
confusing since the initial value of data_len is correct in the 
`size` calculation, while its value inside the while loop it not.

This seem to be syntactically correct, but I think it's better 
practice to avoid shadowing here.

> +

>  	ret = bpf_test_finish(kattr, uattr, xdp.data, size, 

>  retval, duration);

>  out:

>  	bpf_prog_change_xdp(prog, NULL);

> +	for (i = 0; i < sinfo->nr_frags; i++)

> +		__free_page(skb_frag_page(&sinfo->frags[i]));

>  	kfree(data);

> +

>  	return ret;

>  }
Jesper Dangaard Brouer Oct. 8, 2020, 10:46 a.m. UTC | #2
On Thu, 8 Oct 2020 11:06:14 +0300
Shay Agroskin <shayagr@amazon.com> wrote:

> Lorenzo Bianconi <lorenzo@kernel.org> writes:

> 

> > Introduce the capability to allocate a xdp multi-buff in

> > bpf_prog_test_run_xdp routine. This is a preliminary patch to 

> > introduce

> > the selftests for new xdp multi-buff ebpf helpers

> >

> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

> > ---

> >  net/bpf/test_run.c | 51  ++++++++++++++++++++++++++++++++++++++--------

> >  1 file changed, 43 insertions(+), 8 deletions(-)

> >

> > diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c

> > index bd291f5f539c..ec7286cd051b 100644

> > --- a/net/bpf/test_run.c

> > +++ b/net/bpf/test_run.c

> > @@ -617,44 +617,79 @@ int bpf_prog_test_run_xdp(struct bpf_prog 

> > *prog, const union bpf_attr *kattr,

> >  {

> >  	u32 tailroom = SKB_DATA_ALIGN(sizeof(struct 

> >  skb_shared_info));

> >  	u32 headroom = XDP_PACKET_HEADROOM;

> > -	u32 size = kattr->test.data_size_in;

> >  	u32 repeat = kattr->test.repeat;

> >  	struct netdev_rx_queue *rxqueue;

> > +	struct skb_shared_info *sinfo;

> >  	struct xdp_buff xdp = {};

> > +	u32 max_data_sz, size;

> >  	u32 retval, duration;

> > -	u32 max_data_sz;

> > +	int i, ret, data_len;

> >  	void *data;

> > -	int ret;

> >  

> >  	if (kattr->test.ctx_in || kattr->test.ctx_out)

> >  		return -EINVAL;

> >  

> > -	/* XDP have extra tailroom as (most) drivers use full page 

> > */

> >  	max_data_sz = 4096 - headroom - tailroom;  

> 

> For the sake of consistency, can this 4096 be changed to PAGE_SIZE 

> ?


The size 4096 is explicitly use, because the selftest xdp_adjust_tail
expect this, else it will fail on ARCHs with 64K PAGE_SIZE.  It also
seems excessive to create 64K packets for testing XDP.

See: tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c

> Same as in

>      data_len = min_t(int, kattr->test.data_size_in - size, 

>      PAGE_SIZE);

> 

> expression below




-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer
diff mbox series

Patch

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index bd291f5f539c..ec7286cd051b 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -617,44 +617,79 @@  int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 {
 	u32 tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 	u32 headroom = XDP_PACKET_HEADROOM;
-	u32 size = kattr->test.data_size_in;
 	u32 repeat = kattr->test.repeat;
 	struct netdev_rx_queue *rxqueue;
+	struct skb_shared_info *sinfo;
 	struct xdp_buff xdp = {};
+	u32 max_data_sz, size;
 	u32 retval, duration;
-	u32 max_data_sz;
+	int i, ret, data_len;
 	void *data;
-	int ret;
 
 	if (kattr->test.ctx_in || kattr->test.ctx_out)
 		return -EINVAL;
 
-	/* XDP have extra tailroom as (most) drivers use full page */
 	max_data_sz = 4096 - headroom - tailroom;
+	size = min_t(u32, kattr->test.data_size_in, max_data_sz);
+	data_len = size;
 
-	data = bpf_test_init(kattr, kattr->test.data_size_in,
-			     max_data_sz, headroom, tailroom);
+	data = bpf_test_init(kattr, size, max_data_sz, headroom, tailroom);
 	if (IS_ERR(data))
 		return PTR_ERR(data);
 
 	xdp.data_hard_start = data;
 	xdp.data = data + headroom;
 	xdp.data_meta = xdp.data;
-	xdp.data_end = xdp.data + size;
+	xdp.data_end = xdp.data + data_len;
 	xdp.frame_sz = headroom + max_data_sz + tailroom;
 
+	sinfo = xdp_get_shared_info_from_buff(&xdp);
+	if (unlikely(kattr->test.data_size_in > size)) {
+		void __user *data_in = u64_to_user_ptr(kattr->test.data_in);
+
+		while (size < kattr->test.data_size_in) {
+			skb_frag_t *frag = &sinfo->frags[sinfo->nr_frags];
+			struct page *page;
+			int data_len;
+
+			page = alloc_page(GFP_KERNEL);
+			if (!page) {
+				ret = -ENOMEM;
+				goto out;
+			}
+
+			__skb_frag_set_page(frag, page);
+			data_len = min_t(int, kattr->test.data_size_in - size,
+					 PAGE_SIZE);
+			skb_frag_size_set(frag, data_len);
+			if (copy_from_user(page_address(page), data_in + size,
+					   data_len)) {
+				ret = -EFAULT;
+				goto out;
+			}
+			sinfo->nr_frags++;
+			size += data_len;
+		}
+		xdp.mb = 1;
+	}
+
 	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
 	xdp.rxq = &rxqueue->xdp_rxq;
 	bpf_prog_change_xdp(NULL, prog);
 	ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration, true);
 	if (ret)
 		goto out;
+
 	if (xdp.data != data + headroom || xdp.data_end != xdp.data + size)
-		size = xdp.data_end - xdp.data;
+		size += xdp.data_end - xdp.data - data_len;
+
 	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
 out:
 	bpf_prog_change_xdp(prog, NULL);
+	for (i = 0; i < sinfo->nr_frags; i++)
+		__free_page(skb_frag_page(&sinfo->frags[i]));
 	kfree(data);
+
 	return ret;
 }