From: Jianbo Liu Date: Thu, 19 Jun 2025 09:48:51 +0000 (+0300) Subject: xfrm: hold device only for the asynchronous decryption X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b05d42eefac737ce3cd80114d3579111023941b8;p=users%2Fjedix%2Flinux-maple.git xfrm: hold device only for the asynchronous decryption The dev_hold() on skb->dev during packet reception was originally added to prevent the device from being released prematurely during asynchronous decryption operations. As current hardware can offload decryption, this asynchronous path is not always utilized. This often results in a pattern of dev_hold() immediately followed by dev_put() for each packet, creating unnecessary reference counting overhead detrimental to performance. This patch optimizes this by skipping the dev_hold() and subsequent dev_put() when asynchronous decryption is not being performed. Signed-off-by: Jianbo Liu Reviewed-by: Cosmin Ratiu Signed-off-by: Steffen Klassert --- diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index 7e6a71b9d6a3a..c9ddef869aa55 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -503,6 +503,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) /* An encap_type of -1 indicates async resumption. */ if (encap_type == -1) { async = 1; + dev_put(skb->dev); seq = XFRM_SKB_CB(skb)->seq.input.low; goto resume; } @@ -649,18 +650,18 @@ lock: XFRM_SKB_CB(skb)->seq.input.low = seq; XFRM_SKB_CB(skb)->seq.input.hi = seq_hi; - dev_hold(skb->dev); - - if (crypto_done) + if (crypto_done) { nexthdr = x->type_offload->input_tail(x, skb); - else + } else { + dev_hold(skb->dev); + nexthdr = x->type->input(x, skb); + if (nexthdr == -EINPROGRESS) + return 0; - if (nexthdr == -EINPROGRESS) - return 0; + dev_put(skb->dev); + } resume: - dev_put(skb->dev); - spin_lock(&x->lock); if (nexthdr < 0) { if (nexthdr == -EBADMSG) {