From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f48.google.com (mail-ed1-f48.google.com [209.85.208.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FA086AAE for ; Mon, 27 Feb 2023 13:28:42 +0000 (UTC) Received: by mail-ed1-f48.google.com with SMTP id d30so25794201eda.4 for ; Mon, 27 Feb 2023 05:28:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=metaspace-dk.20210112.gappssmtp.com; s=20210112; h=mime-version:message-id:in-reply-to:date:subject:cc:to:from :user-agent:references:from:to:cc:subject:date:message-id:reply-to; bh=+mE5gZc6viG/xXOsPF+F+4EMY6E1n4H7xrKSm+Ny0wU=; b=RPsVl1pelawQdZFTgN5E3b042km9q3OpmP9vlTAn4emotmAngVfbo2/rBicZ1Pdcqg UYEcT4Blo5vl3aTuUFSetJwe+nQQtI/wDeUezLQ58XypftLtLEx49mtLeaY7uOMfPzGQ TJdpPF0ROiLD+uEDJf+tsXWsB+i8iIDr36RK6JyOG+T+rlMiBtpZCJlSd2gb3RRMVyyC UrSdmqYR0QvV6bsS3ZUwIgegzKA28O4nA/Rj9eUMDMSV6kfpBoI06+eJu7Pc+Nfk+OFP FnApEHPONZNf5TPHnrSjqTXbmg+01oeMKes6LRSVYawaUL3/bmaJKkwA5oBEsj/exO2l up0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:message-id:in-reply-to:date:subject:cc:to:from :user-agent:references:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=+mE5gZc6viG/xXOsPF+F+4EMY6E1n4H7xrKSm+Ny0wU=; b=iQuAqqyhMfUoF9Zo+fm8cwH6Xlm8WLdvuk7WB9+48LPTslLhC3CVvRlNHmon+miYTh lr6NeFuYMucNJo67289pDRJC5PsXbZutleCa3ktOcfWLH1xO8GJzCSxlJwpr1lHAAq0X 4eOwzv/dHfuPNcDKIW2RVfqnDWGc0XUY2D8VOOtVC+E2tMKCdyuVF5yAxZWRB5Z/mZp+ 6qniaRVFtaMGTd+m8c7fxdbNZA11+JNgRHK6QDgPaCGCK/Hqww38WqvTvi1zC/iSE1sG wlsMd6Qy2ITuFMb8cVykRuSLD0lBMI8SFlr7Lw1YHtcQlWDgch0jvkz5Z53wcl/jTefo ZWPQ== X-Gm-Message-State: AO0yUKWyq/1PdycnahmnyTZNrhWzT6OtsYbzXY8YPPR35oHZcSpUYv2u MVbbHOvo4XNfi3SyR18NlUFPDg== X-Google-Smtp-Source: AK7set9nqaifHxGsTvMKC77HnKFJJaZIb/iugkiKGlhVtmtoXmZ+i/7pzOdwMnhvj2jkpONQrSu7GA== X-Received: by 2002:a05:6402:31fb:b0:4ac:d2bc:32f9 with SMTP id dy27-20020a05640231fb00b004acd2bc32f9mr24372223edb.4.1677504520550; Mon, 27 Feb 2023 05:28:40 -0800 (PST) Received: from localhost ([194.62.217.2]) by smtp.gmail.com with ESMTPSA id jj22-20020a170907985600b008b17879ec95sm3206035ejc.22.2023.02.27.05.28.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Feb 2023 05:28:40 -0800 (PST) References: <20230224-rust-error-v1-0-f8f9a9a87303@asahilina.net> <20230224-rust-error-v1-2-f8f9a9a87303@asahilina.net> User-agent: mu4e 1.9.18; emacs 28.2.50 From: Andreas Hindborg To: Asahi Lina Cc: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn?= Roy Baron , Sven Van Asbroeck , Fox Chen , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev Subject: Re: [PATCH 2/5] rust: error: Add Error::from_kernel_errno() Date: Mon, 27 Feb 2023 14:27:44 +0100 In-reply-to: <20230224-rust-error-v1-2-f8f9a9a87303@asahilina.net> Message-ID: <87edqb9r08.fsf@metaspace.dk> Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Asahi Lina writes: > From: Miguel Ojeda > > Add a function to create `Error` values out of a kernel error return, > which safely upholds the invariant that the error code is well-formed > (negative and greater than -MAX_ERRNO). If a malformed code is passed > in, it will be converted to EINVAL. > > Lina: Imported from rust-for-linux/rust as authored by Miguel and Fox > with refactoring from Wedson. > > Co-developed-by: Fox Chen > Signed-off-by: Fox Chen > Co-developed-by: Wedson Almeida Filho > Signed-off-by: Wedson Almeida Filho > Signed-off-by: Miguel Ojeda > Signed-off-by: Asahi Lina > --- Reviewed-by: Andreas Hindborg > rust/kernel/error.rs | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs > index 8611758e27f4..3b439fdb405c 100644 > --- a/rust/kernel/error.rs > +++ b/rust/kernel/error.rs > @@ -72,6 +72,25 @@ pub mod code { > pub struct Error(core::ffi::c_int); > > impl Error { > + /// Creates an [`Error`] from a kernel error code. > + /// > + /// It is a bug to pass an out-of-range `errno`. `EINVAL` would > + /// be returned in such a case. > + pub(crate) fn from_kernel_errno(errno: core::ffi::c_int) -> Error { > + if errno < -(bindings::MAX_ERRNO as i32) || errno >= 0 { > + // TODO: Make it a `WARN_ONCE` once available. > + crate::pr_warn!( > + "attempted to create `Error` with out of range `errno`: {}", > + errno > + ); > + return code::EINVAL; > + } > + > + // INVARIANT: The check above ensures the type invariant > + // will hold. > + Error(errno) > + } > + > /// Returns the kernel error code. > pub fn to_kernel_errno(self) -> core::ffi::c_int { > self.0