5.4-stable review patch. If anyone has any objections, please let me know.
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From: Wei Fang wei.fang@nxp.com
[ Upstream commit e59bc32df2e989f034623a580e30a2a72af33b3f ]
The ENETC RX ring uses the page halves flipping mechanism, each page is split into two halves for the RX ring to use. And ENETC_RXB_TRUESIZE is defined to 2048 to indicate the size of half a page. However, the page size is configurable, for ARM64 platform, PAGE_SIZE is default to 4K, but it could be configured to 16K or 64K.
When PAGE_SIZE is set to 16K or 64K, ENETC_RXB_TRUESIZE is not correct, and the RX ring will always use the first half of the page. This is not consistent with the description in the relevant kernel doc and commit messages.
This issue is invisible in most cases, but if users want to increase PAGE_SIZE to receive a Jumbo frame with a single buffer for some use cases, it will not work as expected, because the buffer size of each RX BD is fixed to 2048 bytes.
Based on the above two points, we expect to correct ENETC_RXB_TRUESIZE to (PAGE_SIZE >> 1), as described in the comment.
Fixes: d4fd0404c1c9 ("enetc: Introduce basic PF and VF ENETC ethernet drivers") Signed-off-by: Wei Fang wei.fang@nxp.com Reviewed-by: Claudiu Manoil claudiu.manoil@nxp.com Link: https://patch.msgid.link/20251016080131.3127122-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/freescale/enetc/enetc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/freescale/enetc/enetc.h b/drivers/net/ethernet/freescale/enetc/enetc.h index b8801a2b6a025..6203d117d0d2c 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc.h +++ b/drivers/net/ethernet/freescale/enetc/enetc.h @@ -27,7 +27,7 @@ struct enetc_tx_swbd { };
#define ENETC_RX_MAXFRM_SIZE ENETC_MAC_MAXFRM_SIZE -#define ENETC_RXB_TRUESIZE 2048 /* PAGE_SIZE >> 1 */ +#define ENETC_RXB_TRUESIZE (PAGE_SIZE >> 1) #define ENETC_RXB_PAD NET_SKB_PAD /* add extra space if needed */ #define ENETC_RXB_DMA_SIZE \ (SKB_WITH_OVERHEAD(ENETC_RXB_TRUESIZE) - ENETC_RXB_PAD)