On 13/01/2023 23:31, Toke Høiland-Jørgensen wrote:
Tariq Toukan <ttoukan.linux@xxxxxxxxx> writes:
On 12/01/2023 23:55, Toke Høiland-Jørgensen wrote:
Toke Høiland-Jørgensen <toke@xxxxxxxxxx> writes:
Stanislav Fomichev <sdf@xxxxxxxxxx> writes:
On Thu, Jan 12, 2023 at 12:07 AM Tariq Toukan <ttoukan.linux@xxxxxxxxx> wrote:
On 12/01/2023 2:32, Stanislav Fomichev wrote:
From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Preparation for implementing HW metadata kfuncs. No functional change.
Cc: Tariq Toukan <tariqt@xxxxxxxxxx>
Cc: Saeed Mahameed <saeedm@xxxxxxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Anatoly Burakov <anatoly.burakov@xxxxxxxxx>
Cc: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
Cc: Maryam Tahhan <mtahhan@xxxxxxxxxx>
Cc: xdp-hints@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 1 +
.../net/ethernet/mellanox/mlx5/core/en/xdp.c | 3 +-
.../net/ethernet/mellanox/mlx5/core/en/xdp.h | 6 +-
.../ethernet/mellanox/mlx5/core/en/xsk/rx.c | 25 ++++----
.../net/ethernet/mellanox/mlx5/core/en_rx.c | 58 +++++++++----------
5 files changed, 50 insertions(+), 43 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 2d77fb8a8a01..af663978d1b4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -469,6 +469,7 @@ struct mlx5e_txqsq {
union mlx5e_alloc_unit {
struct page *page;
struct xdp_buff *xsk;
+ struct mlx5e_xdp_buff *mxbuf;
In XSK files below you mix usage of both alloc_units[page_idx].mxbuf and
alloc_units[page_idx].xsk, while both fields share the memory of a union.
As struct mlx5e_xdp_buff wraps struct xdp_buff, I think that you just
need to change the existing xsk field type from struct xdp_buff *xsk
into struct mlx5e_xdp_buff *xsk and align the usage.
Hmmm, good point. I'm actually not sure how it works currently.
mlx5e_alloc_unit.mxbuf doesn't seem to be initialized anywhere? Toke,
am I missing something?
It's initialised piecemeal in different places; but yeah, we're mixing
things a bit...
I'm thinking about something like this:
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h
b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index af663978d1b4..2d77fb8a8a01 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -469,7 +469,6 @@ struct mlx5e_txqsq {
union mlx5e_alloc_unit {
struct page *page;
struct xdp_buff *xsk;
- struct mlx5e_xdp_buff *mxbuf;
};
Hmm, for consistency with the non-XSK path we should rather go the other
direction and lose the xsk member, moving everything to mxbuf? Let me
give that a shot...
Something like the below?
-Toke
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 6de02d8aeab8..cb9cdb6421c5 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -468,7 +468,6 @@ struct mlx5e_txqsq {
union mlx5e_alloc_unit {
struct page *page;
- struct xdp_buff *xsk;
struct mlx5e_xdp_buff *mxbuf;
};
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
index cb568c62aba0..95694a25ec31 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
@@ -33,6 +33,7 @@
#define __MLX5_EN_XDP_H__
#include <linux/indirect_call_wrapper.h>
+#include <net/xdp_sock_drv.h>
#include "en.h"
#include "en/txrx.h"
@@ -112,6 +113,21 @@ static inline void mlx5e_xmit_xdp_doorbell(struct mlx5e_xdpsq *sq)
}
}
+static inline struct mlx5e_xdp_buff *mlx5e_xsk_buff_alloc(struct xsk_buff_pool *pool)
+{
+ return (struct mlx5e_xdp_buff *)xsk_buff_alloc(pool);
What about the space needed for the rq / cqe fields? xsk_buff_alloc
won't allocate it.
It will! See patch 14 in the series that adds a 'cb' field to
xdp_buff_xsk, meaning there's actually space after the xdp_buff struct
being allocated by the xsk_buff_alloc API. The XSK_CHECK_PRIV_TYPE macro
call is there to ensure the cb field is big enough for the struct we're
casting to in the driver.
Oh okay, got it.
+}
+
+static inline void mlx5e_xsk_buff_free(struct mlx5e_xdp_buff *mxbuf)
+{
+ xsk_buff_free(&mxbuf->xdp);
+}
+
+static inline dma_addr_t mlx5e_xsk_buff_xdp_get_frame_dma(struct mlx5e_xdp_buff *mxbuf)
+{
+ return xsk_buff_xdp_get_frame_dma(&mxbuf->xdp);
+}
+
/* Enable inline WQEs to shift some load from a congested HCA (HW) to
* a less congested cpu (SW).
*/
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
index 8bf3029abd3c..1f166dbb7f22 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
@@ -3,7 +3,6 @@
#include "rx.h"
#include "en/xdp.h"
-#include <net/xdp_sock_drv.h>
#include <linux/filter.h>
/* RX data path */
@@ -21,7 +20,7 @@ int mlx5e_xsk_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
if (unlikely(!xsk_buff_can_alloc(rq->xsk_pool, rq->mpwqe.pages_per_wqe)))
goto err;
- BUILD_BUG_ON(sizeof(wi->alloc_units[0]) != sizeof(wi->alloc_units[0].xsk));
+ BUILD_BUG_ON(sizeof(wi->alloc_units[0]) != sizeof(wi->alloc_units[0].mxbuf));
XSK_CHECK_PRIV_TYPE(struct mlx5e_xdp_buff);
batch = xsk_buff_alloc_batch(rq->xsk_pool, (struct xdp_buff **)wi->alloc_units,
rq->mpwqe.pages_per_wqe);
This batching API gets broken as well...
xsk_buff_alloc_batch fills an array of struct xdp_buff pointers, it
cannot correctly act on the array of struct mlx5e_xdp_buff, as it
contains additional fields.
See above for why this does, in fact, work. I agree it's not totally
obvious, and in any case there's going to be a point where the cast
happens where type safety will break, which is what I was alluding to in
my reply to Stanislav.
I guess we could try to rework the API in xdp_sock_drv.h to make this
more obvious instead of using the casting driver-specific wrappers I
suggested here. Or we could go with Stanislav's suggestion of keeping
allocation etc using xdp_buff and only casting to mlx5e_xdp_buff in the
function where it's used; then we can keep the casting localised to that
function, and put a comment there explaining why it works?
Stanislav's proposal LGTM.
Let's keep the casting localised, and make sure there's a comment there.
Maybe letting mlx5e_xdp_buff point to its struct xdp_buff (instead of
wrapping it) will solve the problems here, then we'll loop over the
xdp_buff * array and copy the pointers into the struct mlx5e_xdp_buff *
array.
Need to give it deeper thoughts...
struct mlx5e_xdp_buff {
struct xdp_buff *xdp;
struct mlx5_cqe64 *cqe;
struct mlx5e_rq *rq;
};
This was actually my original proposal; we discussed this back on v2 of
this patch series. People generally felt that the 'cb' field approach
(originally suggested by Jakub) was better.
I agree.
See the discussion starting
from here:
https://lore.kernel.org/r/20221123111431.7b54668e@xxxxxxxxxx
-Toke
