[PATCH net-next 03/12] xdp: make __xdp_return() MP-agnostic
From: Alexander Lobakin
Date: Wed Dec 11 2024 - 12:29:59 EST
Currently, __xdp_return() takes pointer to the virtual memory to free
a buffer. Apart from that this sometimes provokes redundant
data <--> page conversions, taking data pointer effectively prevents
lots of XDP code to support non-page-backed buffers, as there's no
mapping for the non-host memory (data is always NULL).
Just convert it to always take netmem reference. For
xdp_return_{buff,frame*}(), this chops off one page_address() per each
frag and adds one virt_to_netmem() (same as virt_to_page()) per header
buffer. For __xdp_return() itself, it removes one virt_to_page() for
MEM_TYPE_PAGE_POOL and another one for MEM_TYPE_PAGE_ORDER0, adding
one page_address() for [not really common nowadays]
MEM_TYPE_PAGE_SHARED, but the main effect is that the abovementioned
functions won't die or memleak anymore if the frame has non-host memory
attached and will correctly free those.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
---
include/net/xdp.h | 4 ++--
net/core/filter.c | 9 +++------
net/core/xdp.c | 47 +++++++++++++++++++----------------------------
3 files changed, 24 insertions(+), 36 deletions(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 1c260869a353..d2089cfecefd 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -312,8 +312,8 @@ struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
return xdp_frame;
}
-void __xdp_return(void *data, enum xdp_mem_type mem_type, bool napi_direct,
- struct xdp_buff *xdp);
+void __xdp_return(netmem_ref netmem, enum xdp_mem_type mem_type,
+ bool napi_direct, struct xdp_buff *xdp);
void xdp_return_frame(struct xdp_frame *xdpf);
void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
void xdp_return_buff(struct xdp_buff *xdp);
diff --git a/net/core/filter.c b/net/core/filter.c
index 6c036708634b..5fea874025d3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4125,7 +4125,7 @@ static void bpf_xdp_shrink_data_zc(struct xdp_buff *xdp, int shrink,
if (release) {
xsk_buff_del_tail(zc_frag);
- __xdp_return(NULL, mem_type, false, zc_frag);
+ __xdp_return(0, mem_type, false, zc_frag);
} else {
zc_frag->data_end -= shrink;
}
@@ -4142,11 +4142,8 @@ static bool bpf_xdp_shrink_data(struct xdp_buff *xdp, skb_frag_t *frag,
goto out;
}
- if (release) {
- struct page *page = skb_frag_page(frag);
-
- __xdp_return(page_address(page), mem_type, false, NULL);
- }
+ if (release)
+ __xdp_return(skb_frag_netmem(frag), mem_type, false, NULL);
out:
return release;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index d367571c5838..f1165a35411b 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -430,27 +430,25 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_attach_page_pool);
* is used for those calls sites. Thus, allowing for faster recycling
* of xdp_frames/pages in those cases.
*/
-void __xdp_return(void *data, enum xdp_mem_type mem_type, bool napi_direct,
- struct xdp_buff *xdp)
+void __xdp_return(netmem_ref netmem, enum xdp_mem_type mem_type,
+ bool napi_direct, struct xdp_buff *xdp)
{
- struct page *page;
-
switch (mem_type) {
case MEM_TYPE_PAGE_POOL:
- page = virt_to_head_page(data);
+ netmem = netmem_compound_head(netmem);
if (napi_direct && xdp_return_frame_no_direct())
napi_direct = false;
/* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE)
* as mem->type knows this a page_pool page
*/
- page_pool_put_full_page(page->pp, page, napi_direct);
+ page_pool_put_full_netmem(netmem_get_pp(netmem), netmem,
+ napi_direct);
break;
case MEM_TYPE_PAGE_SHARED:
- page_frag_free(data);
+ page_frag_free(__netmem_address(netmem));
break;
case MEM_TYPE_PAGE_ORDER0:
- page = virt_to_page(data); /* Assumes order0 page*/
- put_page(page);
+ put_page(__netmem_to_page(netmem));
break;
case MEM_TYPE_XSK_BUFF_POOL:
/* NB! Only valid from an xdp_buff! */
@@ -466,38 +464,34 @@ void __xdp_return(void *data, enum xdp_mem_type mem_type, bool napi_direct,
void xdp_return_frame(struct xdp_frame *xdpf)
{
struct skb_shared_info *sinfo;
- int i;
if (likely(!xdp_frame_has_frags(xdpf)))
goto out;
sinfo = xdp_get_shared_info_from_frame(xdpf);
- for (i = 0; i < sinfo->nr_frags; i++) {
- struct page *page = skb_frag_page(&sinfo->frags[i]);
+ for (u32 i = 0; i < sinfo->nr_frags; i++)
+ __xdp_return(skb_frag_netmem(&sinfo->frags[i]), xdpf->mem_type,
+ false, NULL);
- __xdp_return(page_address(page), xdpf->mem_type, false, NULL);
- }
out:
- __xdp_return(xdpf->data, xdpf->mem_type, false, NULL);
+ __xdp_return(virt_to_netmem(xdpf->data), xdpf->mem_type, false, NULL);
}
EXPORT_SYMBOL_GPL(xdp_return_frame);
void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
{
struct skb_shared_info *sinfo;
- int i;
if (likely(!xdp_frame_has_frags(xdpf)))
goto out;
sinfo = xdp_get_shared_info_from_frame(xdpf);
- for (i = 0; i < sinfo->nr_frags; i++) {
- struct page *page = skb_frag_page(&sinfo->frags[i]);
+ for (u32 i = 0; i < sinfo->nr_frags; i++)
+ __xdp_return(skb_frag_netmem(&sinfo->frags[i]), xdpf->mem_type,
+ true, NULL);
- __xdp_return(page_address(page), xdpf->mem_type, true, NULL);
- }
out:
- __xdp_return(xdpf->data, xdpf->mem_type, true, NULL);
+ __xdp_return(virt_to_netmem(xdpf->data), xdpf->mem_type, true, NULL);
}
EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
@@ -544,20 +538,17 @@ EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
void xdp_return_buff(struct xdp_buff *xdp)
{
struct skb_shared_info *sinfo;
- int i;
if (likely(!xdp_buff_has_frags(xdp)))
goto out;
sinfo = xdp_get_shared_info_from_buff(xdp);
- for (i = 0; i < sinfo->nr_frags; i++) {
- struct page *page = skb_frag_page(&sinfo->frags[i]);
+ for (u32 i = 0; i < sinfo->nr_frags; i++)
+ __xdp_return(skb_frag_netmem(&sinfo->frags[i]),
+ xdp->rxq->mem.type, true, xdp);
- __xdp_return(page_address(page), xdp->rxq->mem.type, true,
- xdp);
- }
out:
- __xdp_return(xdp->data, xdp->rxq->mem.type, true, xdp);
+ __xdp_return(virt_to_netmem(xdp->data), xdp->rxq->mem.type, true, xdp);
}
EXPORT_SYMBOL_GPL(xdp_return_buff);
--
2.47.1