On 2020-11-27 19:17, Björn Töpel wrote:
From: Björn Töpel <bjorn.topel@xxxxxxxxx>
It turns out that it does exist a path where xdp_return_buff() is
being passed an XDP buffer of type MEM_TYPE_XSK_BUFF_POOL. This path
is when AF_XDP zero-copy mode is enabled, and a buffer is redirected
to a DEVMAP with an attached XDP program that drops the buffer.
This change simply puts the handling of MEM_TYPE_XSK_BUFF_POOL back
into xdp_return_buff().
Reported-by: Maxim Mikityanskiy <maximmi@xxxxxxxxxx>
Fixes: 82c41671ca4f ("xdp: Simplify xdp_return_{frame, frame_rx_napi, buff}")
Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
Thanks for addressing this!
Acked-by: Maxim Mikityanskiy <maximmi@xxxxxxxxxx>
---
net/core/xdp.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 48aba933a5a8..491ad569a79c 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -335,11 +335,10 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
* scenarios (e.g. queue full), it is possible to return the xdp_frame
* while still leveraging this protection. The @napi_direct boolean
* is used for those calls sites. Thus, allowing for faster recycling
- * of xdp_frames/pages in those cases. This path is never used by the
- * MEM_TYPE_XSK_BUFF_POOL memory type, so it's explicitly not part of
- * the switch-statement.
+ * of xdp_frames/pages in those cases.
*/
-static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct)
+static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
+ struct xdp_buff *xdp)
{
struct xdp_mem_allocator *xa;
struct page *page;
@@ -361,6 +360,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct)
page = virt_to_page(data); /* Assumes order0 page*/
put_page(page);
break;
+ case MEM_TYPE_XSK_BUFF_POOL:
+ /* NB! Only valid from an xdp_buff! */
+ xsk_buff_free(xdp);
+ break;
default:
/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
@@ -370,19 +373,19 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct)
void xdp_return_frame(struct xdp_frame *xdpf)
{
- __xdp_return(xdpf->data, &xdpf->mem, false);
+ __xdp_return(xdpf->data, &xdpf->mem, false, NULL);
}
EXPORT_SYMBOL_GPL(xdp_return_frame);
void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
{
- __xdp_return(xdpf->data, &xdpf->mem, true);
+ __xdp_return(xdpf->data, &xdpf->mem, true, NULL);
}
EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
void xdp_return_buff(struct xdp_buff *xdp)
{
- __xdp_return(xdp->data, &xdp->rxq->mem, true);
+ __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
}
/* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
base-commit: 9a44bc9449cfe7e39dbadf537ff669fb007a9e63
