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AJvYcCV1oQbhPywRUF9IKNz1zI6ZC6GuT9ro/mBRbaNQn4a+V/6/zdt1BW7ZFBeyiHGJKaTa6d5wz4xk/hqkLvqT9PfEF4t08pEbSCDh1ItI8GlneLLdLTEL0EHL6tJHQn+/F3gBkcdt X-Gm-Message-State: AOJu0Yx6mqdITLer9K6OGMADZDpY/3Q/Ml7VyKvZv/wqlrVvXGJMmm7q +uuuaEAaMMRGHUcejk2WJsj/ZSsIqOiyuaqWz/h9efF2TtcdUfyzkEQVl9GvLloQIQ== X-Google-Smtp-Source: AGHT+IGmWBuFODJV7ioe217b0PQGyIcD6RxTMMG+fuHy4GLZ88+lqwWk/PMH6SdhzfghGJKAWrZa3g== X-Received: by 2002:a05:6a21:3393:b0:1c1:e75a:5504 with SMTP id adf61e73a8af0-1c29821bb16mr13156121637.15.1720772255334; Fri, 12 Jul 2024 01:17:35 -0700 (PDT) Received: from localhost.localdomain ([240e:604:203:6020:60b8:1bf4:882c:1f7a]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2cacd41a01asm879730a91.32.2024.07.12.01.17.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jul 2024 01:17:34 -0700 (PDT) From: Fred Li To: willemdebruijn.kernel@gmail.com Cc: bpf@vger.kernel.org, herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH] net: linearizing skb when downgrade gso_size Date: Fri, 12 Jul 2024 16:17:24 +0800 Message-Id: <20240712081724.95738-1-dracodingfly@gmail.com> X-Mailer: git-send-email 2.32.1 (Apple Git-133) In-Reply-To: <668d5cf1ec330_1c18c32947@willemb.c.googlers.com.notmuch> References: <668d5cf1ec330_1c18c32947@willemb.c.googlers.com.notmuch> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > No need for ternary statement. > > Instead of the complex test in skb_is_nonsg, can we just assume that > alignment will be off if having frag_list and changing gso_size. > > The same will apply to bpf_skb_net_shrink too. increase gso_size may be no problem and we can use BPF_F_ADJ_ROOM_FIXED_GSO to avoid update gso_size when shrink. > > Not sure that it is okay to linearize inside a BPF helper function. > Hopefully bpf experts can chime in on that. Thanks Fred Li