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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c958cbd21dsm775902185a.42.2025.04.29.13.31.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Apr 2025 13:31:03 -0700 (PDT) Message-ID: <68113707.050a0220.17967c.36c7@mx.google.com> X-Google-Original-Message-ID: Received: from phl-compute-04.internal (phl-compute-04.phl.internal [10.202.2.44]) by mailfauth.phl.internal (Postfix) with ESMTP id 9362D1200068; Tue, 29 Apr 2025 16:31:02 -0400 (EDT) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-04.internal (MEProxy); Tue, 29 Apr 2025 16:31:02 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvieegjeekucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggv pdfurfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpih gvnhhtshculddquddttddmnecujfgurhepfffhvfevuffkfhggtggujgesthdtredttddt vdenucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrih hlrdgtohhmqeenucggtffrrghtthgvrhhnpeehudfgudffffetuedtvdehueevledvhfel leeivedtgeeuhfegueevieduffeivdenucevlhhushhtvghrufhiiigvpedtnecurfgrrh grmhepmhgrihhlfhhrohhmpegsohhquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgr lhhithihqdeiledvgeehtdeigedqudejjeekheehhedvqdgsohhquhhnrdhfvghngheppe hgmhgrihhlrdgtohhmsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohepudehpdhm ohguvgepshhmthhpohhuthdprhgtphhtthhopehjhhhusggsrghrugesnhhvihguihgrrd gtohhmpdhrtghpthhtoheprghlihgtvghrhihhlhesghhoohhglhgvrdgtohhmpdhrtghp thhtohepohhjvggurgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprghkphhmsehlih hnuhigqdhfohhunhgurghtihhonhdrohhrghdprhgtphhtthhopehvihhrohesiigvnhhi vhdrlhhinhhugidrohhrghdruhhkpdhrtghpthhtohepghhrvghgkhhhsehlihhnuhigfh houhhnuggrthhiohhnrdhorhhgpdhrtghpthhtohepghgrrhihsehgrghrhihguhhordhn vghtpdhrtghpthhtohepsghjohhrnhefpghghhesphhrohhtohhnmhgrihhlrdgtohhmpd hrtghpthhtohepsggvnhhnohdrlhhoshhsihhnsehprhhothhonhdrmhgv X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 29 Apr 2025 16:31:01 -0400 (EDT) Date: Tue, 29 Apr 2025 13:31:00 -0700 From: Boqun Feng To: John Hubbard Cc: Alice Ryhl , Miguel Ojeda , Andrew Morton , Alexander Viro , Greg Kroah-Hartman , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Trevor Gross , Danilo Krummrich , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] uaccess: rust: add strncpy_from_user References: <20250429-strncpy-from-user-v2-0-7e6facac0bf0@google.com> <20250429-strncpy-from-user-v2-1-7e6facac0bf0@google.com> <68110cce.c80a0220.3b03fb.43d0@mx.google.com> <0ac7cfba-6b69-439e-a9ee-1175ca8d0913@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0ac7cfba-6b69-439e-a9ee-1175ca8d0913@nvidia.com> On Tue, Apr 29, 2025 at 01:28:09PM -0700, John Hubbard wrote: > On 4/29/25 10:30 AM, Boqun Feng wrote: > > On Tue, Apr 29, 2025 at 09:02:22AM +0000, Alice Ryhl wrote: > ... > >> +#[inline] > >> +pub fn raw_strncpy_from_user(ptr: UserPtr, buf: &mut [MaybeUninit]) -> Result { > >> + // CAST: Slice lengths are guaranteed to be `<= isize::MAX`. > >> + let len = buf.len() as isize; > >> + > >> + // SAFETY: `buf` is valid for writing `buf.len()` bytes. > >> + let res = unsafe { > >> + bindings::strncpy_from_user(buf.as_mut_ptr().cast::(), ptr as *const c_char, len) > >> + }; > >> + > >> + if res < 0 { > >> + return Err(Error::from_errno(res as i32)); > >> + } > >> + > > > > Nit: this can be a > > > > let copy_len = kernel::error::to_result(res)?; > > > > Doesn't that discard the length, though, by returning Ok(()) ? > Oh, you're right, so probably we need a to_result_i32(): pub fn to_result_i32() -> Result , so we don't have to open-code "if res < 0" every time. Regards, Boqun > > thanks, > -- > John Hubbard >