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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4607b119f59sm9611601cf.47.2024.10.15.11.43.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Oct 2024 11:43:29 -0700 (PDT) Received: from phl-compute-03.internal (phl-compute-03.phl.internal [10.202.2.43]) by mailfauth.phl.internal (Postfix) with ESMTP id 721CF1200076; Tue, 15 Oct 2024 14:43:29 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-03.internal (MEProxy); Tue, 15 Oct 2024 14:43:29 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddrvdegjedguddvkecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdp uffrtefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivg hnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtuggjsehttdertddttddv necuhfhrohhmpeeuohhquhhnucfhvghnghcuoegsohhquhhnrdhfvghnghesghhmrghilh drtghomheqnecuggftrfgrthhtvghrnhephedugfduffffteeutddvheeuveelvdfhleel ieevtdeguefhgeeuveeiudffiedvnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrg hmpehmrghilhhfrhhomhepsghoqhhunhdomhgvshhmthhprghuthhhphgvrhhsohhnrghl ihhthidqieelvdeghedtieegqddujeejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepgh hmrghilhdrtghomhesfhhigihmvgdrnhgrmhgvpdhnsggprhgtphhtthhopeduhedpmhho uggvpehsmhhtphhouhhtpdhrtghpthhtoheprghlihgtvgesrhihhhhlrdhiohdprhgtph htthhopegrlhhitggvrhihhhhlsehgohhoghhlvgdrtghomhdprhgtphhtthhopehojhgv uggrsehkvghrnhgvlhdrohhrghdprhgtphhtthhopegrkhhpmheslhhinhhugidqfhhouh hnuggrthhiohhnrdhorhhgpdhrtghpthhtohepfihilhhlhiesihhnfhhrrgguvggrugdr ohhrghdprhgtphhtthhopegrlhgvgidrghgrhihnohhrsehgmhgrihhlrdgtohhmpdhrtg hpthhtohepghgrrhihsehgrghrhihguhhordhnvghtpdhrtghpthhtohepsghjohhrnhef pghghhesphhrohhtohhnmhgrihhlrdgtohhmpdhrtghpthhtohepsggvnhhnohdrlhhosh hsihhnsehprhhothhonhdrmhgv X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 15 Oct 2024 14:43:28 -0400 (EDT) Date: Tue, 15 Oct 2024 11:43:08 -0700 From: Boqun Feng To: Alice Ryhl Cc: Alice Ryhl , Miguel Ojeda , Andrew Morton , "Matthew Wilcox (Oracle)" , Alex Gaynor , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Trevor Gross , linux-mm@kvack.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rust: page: add Rust version of PAGE_ALIGN Message-ID: References: <20241015-page-align-v1-1-68fbd8b6d10c@google.com> <3ea20eb4-2a88-40bd-a453-bf2ff5d52d03@ryhl.io> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3ea20eb4-2a88-40bd-a453-bf2ff5d52d03@ryhl.io> X-Rspamd-Queue-Id: 82BB21C001A X-Stat-Signature: mabkki8ts8piqth6hchser3hgyji377u X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1729017796-220511 X-HE-Meta: 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 URtJOVnL 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Oct 15, 2024 at 08:44:22PM +0200, Alice Ryhl wrote: > On 10/15/24 8:33 PM, Boqun Feng wrote: > > On Tue, Oct 15, 2024 at 02:28:28PM +0000, Alice Ryhl wrote: > > > This is a useful for helper for working with indices into buffers that > > > consist of several pages. I forgot to include it when I added PAGE_SIZE > > > and PAGE_MASK for the same purpose in commit fc6e66f4696b ("rust: add > > > abstraction for `struct page`"). > > > > > > Signed-off-by: Alice Ryhl > > > --- > > > rust/kernel/page.rs | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs > > > index 208a006d587c..90846e3fe829 100644 > > > --- a/rust/kernel/page.rs > > > +++ b/rust/kernel/page.rs > > > @@ -20,6 +20,11 @@ > > > /// A bitmask that gives the page containing a given address. > > > pub const PAGE_MASK: usize = !(PAGE_SIZE - 1); > > > +/// Round up the given number to a multiple of `PAGE_SIZE`. > > > +pub fn page_align(addr: usize) -> usize { > > > > Make it a `const` function? For example, there is a VMBUS_RING_SIZE() > > macro in C that calculates a const number for a vmbus ringbuffer size, > > so it will be useful. > > Good idea. > > > > + (addr + (PAGE_SIZE - 1)) & PAGE_MASK > > > > I guess overflows are unexpected, i.e. the users should not pass a > > `addr` that `> usize::MAX - PAGE_SIZE + 1`? > Correct. If this wraps around to zero, that's incorrect. Note that the minus > one is in brackets to only trigger overflow detection in the right cases. > Make senses, with the const change and some docs on the overflow case, feel free to add: Reviewed-by: Boqun Feng Regards, Boqun > I can mention this in the docs. > > Alice