diff mbox series

[v2,net-next,3/3] net: ethernet: enetc: do not always access skb_shared_info in the XDP path

Message ID 8a8d98a84ae48629564e2fb09c4a378bb0a18b1c.1672840490.git.lorenzo@kernel.org (mailing list archive)
State Accepted
Commit c7030d14c78e634b94616a08f4961d767f645834
Delegated to: Netdev Maintainers
Headers show
Series enetc: unlock XDP_REDIRECT for XDP non-linear buffers | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 5 maintainers not CCed: bpf@vger.kernel.org ast@kernel.org daniel@iogearbox.net john.fastabend@gmail.com hawk@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 56 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Lorenzo Bianconi Jan. 4, 2023, 1:57 p.m. UTC 
Move XDP skb_shared_info structure initialization in from
enetc_map_rx_buff_to_xdp() to enetc_add_rx_buff_to_xdp() and do not always
access skb_shared_info in the xdp_buff/xdp_frame since it is located in a
different cacheline with respect to hard_start and data xdp pointers.
Rely on XDP_FLAGS_HAS_FRAGS flag to check if it really necessary to access
non-linear part of the xdp_buff/xdp_frame.

Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/freescale/enetc/enetc.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Comments

Leon Romanovsky Jan. 5, 2023, 9:07 a.m. UTC | #1 
On Wed, Jan 04, 2023 at 02:57:12PM +0100, Lorenzo Bianconi wrote:
> Move XDP skb_shared_info structure initialization in from
> enetc_map_rx_buff_to_xdp() to enetc_add_rx_buff_to_xdp() and do not always
> access skb_shared_info in the xdp_buff/xdp_frame since it is located in a
> different cacheline with respect to hard_start and data xdp pointers.
> Rely on XDP_FLAGS_HAS_FRAGS flag to check if it really necessary to access
> non-linear part of the xdp_buff/xdp_frame.
> 
> Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/net/ethernet/freescale/enetc/enetc.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 18a01f6282b6..5ad0b259e623 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -1305,6 +1305,10 @@  static int enetc_xdp_frame_to_xdp_tx_swbd(struct enetc_bdr *tx_ring,
 	xdp_tx_swbd->xdp_frame = NULL;
 
 	n++;
+
+	if (!xdp_frame_has_frags(xdp_frame))
+		goto out;
+
 	xdp_tx_swbd = &xdp_tx_arr[n];
 
 	shinfo = xdp_get_shared_info_from_frame(xdp_frame);
@@ -1334,7 +1338,7 @@  static int enetc_xdp_frame_to_xdp_tx_swbd(struct enetc_bdr *tx_ring,
 		n++;
 		xdp_tx_swbd = &xdp_tx_arr[n];
 	}
-
+out:
 	xdp_tx_arr[n - 1].is_eof = true;
 	xdp_tx_arr[n - 1].xdp_frame = xdp_frame;
 
@@ -1390,16 +1394,12 @@  static void enetc_map_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
 {
 	struct enetc_rx_swbd *rx_swbd = enetc_get_rx_buff(rx_ring, i, size);
 	void *hard_start = page_address(rx_swbd->page) + rx_swbd->page_offset;
-	struct skb_shared_info *shinfo;
 
 	/* To be used for XDP_TX */
 	rx_swbd->len = size;
 
 	xdp_prepare_buff(xdp_buff, hard_start - rx_ring->buffer_offset,
 			 rx_ring->buffer_offset, size, false);
-
-	shinfo = xdp_get_shared_info_from_buff(xdp_buff);
-	shinfo->nr_frags = 0;
 }
 
 static void enetc_add_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
@@ -1407,7 +1407,7 @@  static void enetc_add_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
 {
 	struct skb_shared_info *shinfo = xdp_get_shared_info_from_buff(xdp_buff);
 	struct enetc_rx_swbd *rx_swbd = enetc_get_rx_buff(rx_ring, i, size);
-	skb_frag_t *frag = &shinfo->frags[shinfo->nr_frags];
+	skb_frag_t *frag;
 
 	/* To be used for XDP_TX */
 	rx_swbd->len = size;
@@ -1415,6 +1415,7 @@  static void enetc_add_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
 	if (!xdp_buff_has_frags(xdp_buff)) {
 		xdp_buff_set_frags_flag(xdp_buff);
 		shinfo->xdp_frags_size = size;
+		shinfo->nr_frags = 0;
 	} else {
 		shinfo->xdp_frags_size += size;
 	}
@@ -1422,6 +1423,7 @@  static void enetc_add_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
 	if (page_is_pfmemalloc(rx_swbd->page))
 		xdp_buff_set_frag_pfmemalloc(xdp_buff);
 
+	frag = &shinfo->frags[shinfo->nr_frags];
 	skb_frag_off_set(frag, rx_swbd->page_offset);
 	skb_frag_size_set(frag, size);
 	__skb_frag_set_page(frag, rx_swbd->page);