From 3bfc69abf802f56901ffd83bb66b7dd7644ddcc3 Mon Sep 17 00:00:00 2001 From: Dean Jenkins Date: Fri, 2 Oct 2015 14:29:05 +0100 Subject: [PATCH] asix: Tidy-up 32-bit header word synchronisation Tidy-up the Data header 32-bit word synchronisation logic in asix_rx_fixup_internal() by removing redundant logic tests. The code is looking at the following cases of the Data header 32-bit word that is present before each Ethernet frame: a) all 32 bits of the Data header word are in the URB socket buffer b) first 16 bits of the Data header word are at the end of the URB socket buffer c) last 16 bits of the Data header word are at the start of the URB socket buffer eg. split_head = true Note that the lifetime of rx->split_head exists outside of the function call and is accessed per processing of each URB. Therefore, split_head being true acts on the next URB to be processed. To check for b) the offset will be 16 bits (2 bytes) from the end of the buffer then indicate split_head is true. To check for c) split_head must be true because the first 16 bits have been found. To check for a) else c) Note that the || logic of the old code included the state (skb->len - offset == sizeof(u16) && rx->split_head) which is not possible because the split_head cannot be true whilst checking for b). This is because the split_head indicates that the first 16 bits have been found and that is not possible whilst checking for the first 16 bits. Therefore simplify the logic. Signed-off-by: Dean Jenkins Signed-off-by: Mark Craske Signed-off-by: David S. Miller --- drivers/net/usb/asix_common.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c index 2bd5bdda8c2e..89efd6ad9644 100644 --- a/drivers/net/usb/asix_common.c +++ b/drivers/net/usb/asix_common.c @@ -61,21 +61,19 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb, unsigned char *data; if (!rx->remaining) { - if ((skb->len - offset == sizeof(u16)) || - rx->split_head) { - if(!rx->split_head) { - rx->header = get_unaligned_le16( - skb->data + offset); - rx->split_head = true; - offset += sizeof(u16); - break; - } else { - rx->header |= (get_unaligned_le16( - skb->data + offset) - << 16); - rx->split_head = false; - offset += sizeof(u16); - } + if (skb->len - offset == sizeof(u16)) { + rx->header = get_unaligned_le16( + skb->data + offset); + rx->split_head = true; + offset += sizeof(u16); + break; + } + + if (rx->split_head == true) { + rx->header |= (get_unaligned_le16( + skb->data + offset) << 16); + rx->split_head = false; + offset += sizeof(u16); } else { rx->header = get_unaligned_le32(skb->data + offset); -- 2.20.1