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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49571c4b664sm44359805e9.4.2026.07.23.01.12.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2026 01:12:31 -0700 (PDT) Date: Thu, 23 Jul 2026 09:12:29 +0100 From: David Laight To: Bart Van Assche Cc: Bean Huo , Li Qiang , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, alim.akhtar@samsung.com, avri.altman@wdc.com, James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, peter.wang@mediatek.com, beanhuo@micron.com, can.guo@oss.qualcomm.com, adrian.hunter@intel.com, tomas.winkler@intel.com Subject: Re: [PATCH v2 5/6] scsi: ufs: rpmb: Use unaligned accessors for RPMB frames Message-ID: <20260723091229.72bc2da8@pumpkin> In-Reply-To: References: <20260717153914.26321-1-liqiang01@kylinos.cn> <20260717153914.26321-6-liqiang01@kylinos.cn> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 22 Jul 2026 06:54:16 -0700 Bart Van Assche wrote: > On 7/22/26 5:33 AM, Bean Huo wrote: > > consider Sashiko's suggestion, it's better to add __packed on struct rpmb_frame > > {}? > > Do not add __packed to an entire data structure. Only use it on > data structure members that need it. That depends... If the structure itself can be misaligned in memory then the structure needs to be packed. OTOH if there is (for example) a 32bit field on a 16bit boundary then just marking that field __packed will remove the pad. The compiler can then use two 16bit instructions to access the data rather than four 8bit ones. David > > Thanks, > > Bart. >