Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 14:11:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

xsk: Add option to calculate TX checksum in SW

Browse Source 
For XDP_COPY mode, add a UMEM option XDP_UMEM_TX_SW_CSUM
to call skb_checksum_help in transmit path. Might be useful
to debugging issues with real hardware. I also use this mode
in the selftests.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231127190319.1190813-9-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Stanislav Fomichev 2023-11-27 11:03:14 -08:00 committed by Alexei Starovoitov
parent ce59f9686e
commit 11614723af
7 changed files with 37 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Documentation/networking/xsk-tx-metadata.rst
View File

@ -50,6 +50,15 @@ packet's ``struct xdp_desc`` descriptor should set ``XDP_TX_METADATA``
bit in the ``options`` field. Also note that in a multi-buffer packet
only the first chunk should carry the metadata.
Software TX Checksum
====================
For development and testing purposes its possible to pass
``XDP_UMEM_TX_SW_CSUM`` flag to ``XDP_UMEM_REG`` UMEM registration call.
In this case, when running in ``XDK_COPY`` mode, the TX checksum
is calculated on the CPU. Do not enable this option in production because
it will negatively affect performance.
Querying Device Capabilities
============================

1
include/net/xsk_buff_pool.h
View File

@ -83,6 +83,7 @@ struct xsk_buff_pool {
bool uses_need_wakeup;
bool dma_need_sync;
bool unaligned;
bool tx_sw_csum;
void *addrs;
/* Mutual exclusion of the completion ring in the SKB mode. Two cases to protect:
* NAPI TX thread and sendmsg error paths in the SKB destructor callback and when

8
include/uapi/linux/if_xdp.h
View File

@ -33,7 +33,13 @@
#define XDP_USE_SG (1 << 4)
/* Flags for xsk_umem_config flags */
#define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
#define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
/* Force checksum calculation in software. Can be used for testing or
* working around potential HW issues. This option causes performance
* degradation and only works in XDP_COPY mode.
*/
#define XDP_UMEM_TX_SW_CSUM (1 << 1)
struct sockaddr_xdp {
__u16 sxdp_family;

7
net/xdp/xdp_umem.c
View File

@ -148,6 +148,11 @@ static int xdp_umem_account_pages(struct xdp_umem *umem)
return 0;
}
#define XDP_UMEM_FLAGS_VALID ( \
XDP_UMEM_UNALIGNED_CHUNK_FLAG | \
XDP_UMEM_TX_SW_CSUM | \
0)
static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
{
bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
@ -167,7 +172,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
return -EINVAL;
}
if (mr->flags & ~XDP_UMEM_UNALIGNED_CHUNK_FLAG)
if (mr->flags & ~XDP_UMEM_FLAGS_VALID)
return -EINVAL;
if (!unaligned_chunks && !is_power_of_2(chunk_size))

6
net/xdp/xsk.c
View File

@ -744,6 +744,12 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
skb->csum_start = hr + meta->request.csum_start;
skb->csum_offset = meta->request.csum_offset;
skb->ip_summed = CHECKSUM_PARTIAL;
if (unlikely(xs->pool->tx_sw_csum)) {
err = skb_checksum_help(skb);
if (err)
goto free_err;
}
}
}
}

1
net/xdp/xsk_buff_pool.c
View File

@ -86,6 +86,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
pool->umem = umem;
pool->addrs = umem->addrs;
pool->tx_metadata_len = umem->tx_metadata_len;
pool->tx_sw_csum = umem->flags & XDP_UMEM_TX_SW_CSUM;
INIT_LIST_HEAD(&pool->free_list);
INIT_LIST_HEAD(&pool->xskb_list);
INIT_LIST_HEAD(&pool->xsk_tx_list);

8
tools/include/uapi/linux/if_xdp.h
View File

@ -33,7 +33,13 @@
#define XDP_USE_SG (1 << 4)
/* Flags for xsk_umem_config flags */
#define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
#define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
/* Force checksum calculation in software. Can be used for testing or
* working around potential HW issues. This option causes performance
* degradation and only works in XDP_COPY mode.
*/
#define XDP_UMEM_TX_SW_CSUM (1 << 1)
struct sockaddr_xdp {
__u16 sxdp_family;