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Date:   Wed, 06 May 2020 14:52:20 -0700 (PDT)
Message-Id: <20200506.145220.1567628861970386108.davem@davemloft.net>
To:     ayush.sawal@chelsio.com
Cc:     herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org,
        netdev@vger.kernel.org, manojmalaviya@chelsio.com
Subject: Re: [PATCH net-next] Revert "crypto: chelsio - Inline single pdu
 only"
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20200506144719.3725-1-ayush.sawal@chelsio.com>
References: <20200506144719.3725-1-ayush.sawal@chelsio.com>
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From: Ayush Sawal <ayush.sawal@chelsio.com>
Date: Wed,  6 May 2020 20:17:19 +0530

> This reverts commit 27c6feb0fb33a665a746346e76714826a5be5d10.
> 
> For ipsec offload the chelsio's ethernet driver expects a single mtu
> sized packet.
> 
> But when ipsec traffic is running using iperf, most of the packets in
> that traffic are gso packets(large sized skbs) because GSO is enabled by
> default in TCP, due to this commit 0a6b2a1dc2a2 ("tcp: switch to GSO
> being always on"), so chcr_ipsec_offload_ok() receives a gso
> skb(with gso_size non zero).
> 
> Due to the check in chcr_ipsec_offload_ok(), this function returns false
> for most of the packet, then ipsec offload is skipped and the skb goes
> out taking the coprocessor path which reduces the bandwidth for inline
> ipsec.
> 
> If this check is removed then for most of the packets(large sized skbs)
> the chcr_ipsec_offload_ok() returns true and then as GSO is on, the
> segmentation of the packet happens in the kernel and then finally the
> driver_xmit is called, which receives a segmented mtu sized packet which
> is what the driver expects for ipsec offload. So this case becomes
> unnecessary here, therefore removing it.
> 
> Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>

Applied.