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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43943cd4442sm10137305e9.24.2025.02.09.11.02.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Feb 2025 11:02:12 -0800 (PST) Date: Sun, 9 Feb 2025 19:02:11 +0000 From: David Laight To: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Christian Brauner , Jan Kara , Arnd Bergmann , Kees Cook Subject: Re: [PATCH 1/2] uaccess: Simplify code pattern for masked user copies Message-ID: <20250209190211.5a11d6d6@pumpkin> In-Reply-To: References: <20250209105600.3388-1-david.laight.linux@gmail.com> <20250209105600.3388-2-david.laight.linux@gmail.com> <20250209183437.340dcee6@pumpkin> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-fsdevel@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 Sun, 9 Feb 2025 10:46:03 -0800 Linus Torvalds wrote: > On Sun, 9 Feb 2025 at 10:40, Linus Torvalds > wrote: > > > > It's *really* easy to miss the "oh, that changes X" when the only > > little tiny sign of it is that "&" character inside the argument list, > > and then the *normal* mental model is that arguments are arguments > > *to* the function, not returns *from* the function. > > While I'm ranting, this is just another case of "C++ really got this > very very wrong". > > C++ made pass-by-reference really easy, and removed the need for even > that tiny marker in the caller. > > So then you really can't even visually see that "oh, that call changes > its argument", and have to just know. Or make a habit of appending '+ 0' to every argument :-) > > Linus