xsk: honor XDP_TX_METADATA in zero-copy path

The zero-copy path reads TX metadata whenever the UMEM has metadata space,
even if the descriptor does not set XDP_TX_METADATA. Pass descriptor
options through the metadata helpers and ignore metadata unless the option
is set.

This does not fix the existing per-WQE metadata handling for mlx5 MPWQEs.
Only the descriptor that starts a session passes through
xsk_tx_metadata_request() and configures offload state shared by the batch.
Metadata on descriptors joining an open session is therefore not validated
and does not configure its requested offloads. In addition, a non-NULL
metadata pointer from such a descriptor is treated as a timestamp
completion request even when XDP_TXMD_FLAGS_TIMESTAMP is not set, so its
metadata union can be overwritten with an unrequested timestamp. Fixing
mixed metadata states within one MPWQE requires a separate change.

Fixes: 48eb03dd2630 ("xsk: Add TX timestamp and TX checksum offload support")
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Link: https://patch.msgid.link/20260819160535.1472459-3-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 8b9ce7c..1fb5f3c 100644 (file)
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -3071,7 +3071,8 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring)
                olinfo_status = xdp_desc.len << IGC_ADVTXD_PAYLEN_SHIFT;
 
                dma = xsk_buff_raw_get_dma(pool, xdp_desc.addr);
-               meta = xsk_buff_get_metadata(pool, xdp_desc.addr);
+               meta = xsk_buff_get_metadata(pool, xdp_desc.addr,
+                                            xdp_desc.options);
                xsk_buff_raw_dma_sync_for_device(pool, dma, xdp_desc.len);
                bi = &ring->tx_buffer_info[ntu];
 

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
index 3d19dad..d194eed 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
@@ -99,7 +99,7 @@ bool mlx5e_xsk_tx(struct mlx5e_xdpsq *sq, unsigned int budget)
                xdptxd.dma_addr = xsk_buff_raw_get_dma(pool, desc.addr);
                xdptxd.data = xsk_buff_raw_get_data(pool, desc.addr);
                xdptxd.len = desc.len;
-               meta = xsk_buff_get_metadata(pool, desc.addr);
+               meta = xsk_buff_get_metadata(pool, desc.addr, desc.options);
 
                xsk_buff_raw_dma_sync_for_device(pool, xdptxd.dma_addr, xdptxd.len);
 

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b2b7d02..efa35cf 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2723,7 +2723,8 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 
                tx_desc = stmmac_get_tx_desc(priv, tx_q, entry);
                dma_addr = xsk_buff_raw_get_dma(pool, xdp_desc.addr);
-               meta = xsk_buff_get_metadata(pool, xdp_desc.addr);
+               meta = xsk_buff_get_metadata(pool, xdp_desc.addr,
+                                            xdp_desc.options);
                xsk_buff_raw_dma_sync_for_device(pool, dma_addr, xdp_desc.len);
 
                /* To return XDP buffer to XSK pool, we simple call

diff --git a/include/net/libeth/xsk.h b/include/net/libeth/xsk.h
index 5dcc0d7..a452b78 100644 (file)
--- a/include/net/libeth/xsk.h
+++ b/include/net/libeth/xsk.h
@@ -196,7 +196,7 @@ __libeth_xsk_xmit_fill_buf_md(const struct xdp_desc *xdesc,
        struct libeth_xdp_tx_desc desc;
        struct xdp_desc_ctx ctx;
 
-       ctx = xsk_buff_raw_get_ctx(sq->pool, xdesc->addr);
+       ctx = xsk_buff_raw_get_ctx(sq->pool, xdesc->addr, xdesc->options);
        desc = (typeof(desc)){
                .addr   = ctx.dma,
                __libeth_xdp_tx_len(xdesc->len),

diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index b344789..d94aeb5 100644 (file)
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -240,6 +240,7 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
  * xsk_buff_raw_get_ctx - get &xdp_desc context
  * @pool: XSk buff pool desc address belongs to
  * @addr: desc address (from userspace)
+ * @options: desc options (from userspace)
  *
  * Wrapper for xp_raw_get_ctx() to be used in drivers, see its kdoc for
  * details.
@@ -248,9 +249,9 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
  * pointer, if it is present (initialized to %NULL otherwise).
  */
 static inline struct xdp_desc_ctx
-xsk_buff_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
+xsk_buff_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr, u32 options)
 {
-       return xp_raw_get_ctx(pool, addr);
+       return xp_raw_get_ctx(pool, addr, options);
 }
 
 #define XDP_TXMD_FLAGS_VALID ( \
@@ -318,18 +319,20 @@ xsk_tx_metadata_request(const struct xsk_buff_pool *pool,
 }
 
 static inline struct xsk_tx_metadata *
-__xsk_buff_get_metadata(const struct xsk_buff_pool *pool, void *data)
+__xsk_buff_get_metadata(const struct xsk_buff_pool *pool, void *data,
+                       unsigned int options)
 {
-       if (!pool->tx_metadata_len)
+       if (!pool->tx_metadata_len || !(options & XDP_TX_METADATA))
                return NULL;
 
        return data - pool->tx_metadata_len;
 }
 
 static inline struct xsk_tx_metadata *
-xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr)
+xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr, u32 options)
 {
-       return __xsk_buff_get_metadata(pool, xp_raw_get_data(pool, addr));
+       return __xsk_buff_get_metadata(pool, xp_raw_get_data(pool, addr),
+                                      options);
 }
 
 static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp)
@@ -510,7 +513,7 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 }
 
 static inline struct xdp_desc_ctx
-xsk_buff_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
+xsk_buff_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr, u32 options)
 {
        return (struct xdp_desc_ctx){ };
 }
@@ -530,13 +533,14 @@ xsk_tx_metadata_request(const struct xsk_buff_pool *pool,
 }
 
 static inline struct xsk_tx_metadata *
-__xsk_buff_get_metadata(const struct xsk_buff_pool *pool, void *data)
+__xsk_buff_get_metadata(const struct xsk_buff_pool *pool, void *data,
+                       unsigned int options)
 {
        return NULL;
 }
 
 static inline struct xsk_tx_metadata *
-xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr)
+xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr, u32 options)
 {
        return NULL;
 }

diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 2bb1d12..a7df573 100644 (file)
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -154,7 +154,8 @@ struct xdp_desc_ctx {
        struct xsk_tx_metadata *meta;
 };
 
-struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr);
+struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr,
+                                  u32 options);
 
 static inline dma_addr_t xp_get_dma(struct xdp_buff_xsk *xskb)
 {

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 78c14f1..9d2d94f 100644 (file)
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -763,6 +763,7 @@ EXPORT_SYMBOL(xp_raw_get_dma);
  * xp_raw_get_ctx - get &xdp_desc context
  * @pool: XSk buff pool desc address belongs to
  * @addr: desc address (from userspace)
+ * @options: desc options (from userspace)
  *
  * Helper for getting desc's DMA address and metadata pointer, if present.
  * Saves one call on hotpath and double calculation of the actual address.
@@ -771,14 +772,16 @@ EXPORT_SYMBOL(xp_raw_get_dma);
  * Return: new &xdp_desc_ctx struct containing desc's DMA address and metadata
  * pointer, if it is present (initialized to %NULL otherwise).
  */
-struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
+struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr,
+                                  u32 options)
 {
        struct xdp_desc_ctx ret;
 
        addr = __xp_raw_get_addr(pool, addr);
 
        ret.dma = __xp_raw_get_dma(pool, addr);
-       ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr));
+       ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr),
+                                          options);
 
        return ret;
 }