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([2620:10d:c092:600::1:72cc]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ae6e7eec2a0sm1338371766b.67.2025.07.17.02.21.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 17 Jul 2025 02:22:01 -0700 (PDT) Message-ID: <325c6297-b47f-43ad-8d2f-276cf70f3d57@gmail.com> Date: Thu, 17 Jul 2025 10:23:25 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v10 02/12] netmem: use netmem_desc instead of page to access ->pp in __netmem_get_pp() From: Pavel Begunkov To: Mina Almasry , Byungchul Park , "Lobakin, Aleksander" Cc: willy@infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, ilias.apalodimas@linaro.org, harry.yoo@oracle.com, akpm@linux-foundation.org, andrew+netdev@lunn.ch, toke@redhat.com, david@redhat.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, vishal.moola@gmail.com, hannes@cmpxchg.org, ziy@nvidia.com, jackmanb@google.com, wei.fang@nxp.com, shenwei.wang@nxp.com, xiaoning.wang@nxp.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, anthony.l.nguyen@intel.com, przemyslaw.kitszel@intel.com, sgoutham@marvell.com, gakula@marvell.com, sbhatta@marvell.com, hkelam@marvell.com, bbhushan2@marvell.com, tariqt@nvidia.com, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, saeedm@nvidia.com, leon@kernel.org, mbloch@nvidia.com, danishanwar@ti.com, rogerq@kernel.org, nbd@nbd.name, lorenzo@kernel.org, ryder.lee@mediatek.com, shayne.chen@mediatek.com, sean.wang@mediatek.com, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, horms@kernel.org, m-malladi@ti.com, krzysztof.kozlowski@linaro.org, matthias.schiffer@ew.tq-group.com, robh@kernel.org, imx@lists.linux.dev, intel-wired-lan@lists.osuosl.org, linux-arm-kernel@lists.infradead.org, linux-wireless@vger.kernel.org, linux-mediatek@lists.infradead.org References: <20250714120047.35901-1-byungchul@sk.com> <20250714120047.35901-3-byungchul@sk.com> <20250715013626.GA49874@system.software.com> <20250716045124.GB12760@system.software.com> <6e4a4ae7-b84e-470d-81e9-a58ecf9c9157@gmail.com> Content-Language: en-US In-Reply-To: <6e4a4ae7-b84e-470d-81e9-a58ecf9c9157@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 7/17/25 10:17, Pavel Begunkov wrote: > On 7/16/25 20:41, Mina Almasry wrote: > ...>> I will kill __netmem_get_pp() as you and I prefer.  However, >>> __netmem_get_pp() users e.i. libeth_xdp_return_va() and >>> libeth_xdp_tx_fill_buf() should be altered.  I will modify the code like: >>> >>> as is: __netmem_get_pp(netmem) >>> to be: __netmem_nmdesc(netmem)->pp >>> >>> Is it okay with you? >>> >> >> When Pavel and I were saying 'remove __netmem_get_pp', I think we >> meant to remove the entire concept of unsafe netmem -> page >> conversions. I think we both don't like them. From this perspective, >> __netmem_nmdesc(netmem)->pp is just as bad as __netmem_get_pp(netmem). > > Yes. It'd great to have all of them gone. IMHO it's much better > to let the caller do the casting so at least it's explicit and > assumptions are not hidden. E.g. instead of > > pp = __netmem_nmdesc(netmem)->pp; > > It'd be > > struct page *page = __netmem_to_page(netmem); > > page_to_nmdesc(page)->pp; > // or page_get_pp(page), or whatever the helper is > > That might be easier as well. FWIW, no need to respin a v12 for that -- Pavel Begunkov