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Miller" , "Simon Horman" , "Abdiel Janulgue" , "Daniel Almeida" , "Robin Murphy" , "Andreas Hindborg" , "Boqun Feng" , "Gary Guo" , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , "Benno Lossin" , "Alice Ryhl" , "Trevor Gross" , "Tamir Duberstein" , "Alexandre Courbot" , =?utf-8?q?Onur_=C3=96zkan?= , "Greg Kroah-Hartman" , , , , Subject: Re: [PATCH v2 3/3] rust: dma.rs: Migrate to zerocopy's `Frombytes/IntoBytes` From: "Gary Guo" X-Mailer: aerc 0.22.0 References: <20260906102826.202874-1-sagartaunk@proton.me> <20260906102826.202874-4-sagartaunk@proton.me> In-Reply-To: <20260906102826.202874-4-sagartaunk@proton.me> X-ClientProxiedBy: LO4P123CA0308.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:197::7) To LOAP265MB8560.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:4ab::19) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LOAP265MB8560:EE_|LO0P265MB2699:EE_ X-MS-Office365-Filtering-Correlation-Id: 60d9344c-790e-46a3-c059-08df0c150160 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|10070799003|376014|1800799024|23010399003|366016|4143699003|56012099006|6133799003|18002099003|22082099003|10067099003; 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Are all users of `CoherentBox` already have the both zerocopy and kernel traits implemented? Best, Gary > --- > rust/kernel/dma.rs | 22 +++++++++------------- > 1 file changed, 9 insertions(+), 13 deletions(-) > > diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs > index 2ce09f8e90c6..9bd47f20c784 100644 > --- a/rust/kernel/dma.rs > +++ b/rust/kernel/dma.rs > @@ -25,10 +25,6 @@ > prelude::*, > ptr::KnownSize, > sync::aref::ARef, > - transmute::{ > - AsBytes, > - FromBytes, // > - }, > uaccess::UserSliceWriter, // > }; > use core::{ > @@ -417,7 +413,7 @@ fn from(direction: DataDirection) -> Self { > /// ``` > pub struct CoherentBox(Coherent); > =20 > -impl CoherentBox<[T]> { > +impl CoherentBox<[T]> { > /// [`CoherentBox`] variant of [`Coherent::zeroed_slice_with_attrs`]= . > #[inline] > pub fn zeroed_slice_with_attrs( > @@ -454,7 +450,7 @@ pub fn init_at(&mut self, i: usize, init: impl Ini= t) -> Result > =20 > // SAFETY: > // - `ptr` is valid, properly aligned, and within this allocatio= n. > - // - `T: AsBytes + FromBytes` guarantees all bit patterns are va= lid, so partial writes on > + // - `T: IntoBytes + FromBytes` guarantees all bit patterns are = valid, so partial writes on > // error cannot leave the element in an invalid state. > // - The DMA address has not been exposed yet, so there is no co= ncurrent device access. > unsafe { pin_init::raw_try_init(ptr, init)? }; > @@ -523,7 +519,7 @@ pub fn from_slice( > } > } > =20 > -impl CoherentBox { > +impl CoherentBox { > /// Same as [`CoherentBox::zeroed_slice_with_attrs`], but for a sing= le element. > #[inline] > pub fn zeroed_with_attrs( > @@ -554,7 +550,7 @@ fn deref(&self) -> &Self::Target { > } > } > =20 > -impl DerefMut for CoherentB= ox { > +impl DerefMut for Coheren= tBox { > #[inline] > fn deref_mut(&mut self) -> &mut Self::Target { > // SAFETY: > @@ -565,7 +561,7 @@ fn deref_mut(&mut self) -> &mut Self::Target { > } > } > =20 > -impl From> f= or Coherent { > +impl From>= for Coherent { > #[inline] > fn from(value: CoherentBox) -> Self { > value.0 > @@ -663,7 +659,7 @@ pub unsafe fn as_mut(&self) -> &mut T { > } > } > =20 > -impl Coherent { > +impl Coherent { > /// Allocates a region of `T` of coherent memory. > fn alloc_with_attrs( > dev: &device::Device, > @@ -753,7 +749,7 @@ pub fn init_with_attrs( > // SAFETY: > // - `ptr` is valid, properly aligned, and points to exclusively= owned memory. > // - If `raw_try_init` fails, `self` is dropped, which safely fr= ees the underlying > - // `Coherent`'s DMA memory. `T: AsBytes + FromBytes` ensures t= here are no complex `Drop` > + // `Coherent`'s DMA memory. `T: IntoBytes + FromBytes` ensures= there are no complex `Drop` > // requirements we are bypassing. > unsafe { pin_init::raw_try_init(ptr, init)? }; > =20 > @@ -948,9 +944,9 @@ unsafe impl Send for Co= herent {} > // methods that access the buffer contents (`field_read`, `field_write`,= `as_slice`, > // `as_slice_mut`) are `unsafe`, and callers are responsible for ensurin= g no data races occur. > // The safe methods only return metadata or raw pointers whose use requi= res `unsafe`. > -unsafe impl Sync for= Coherent {} > +unsafe impl Sync f= or Coherent {} > =20 > -impl debugfs::BinaryWriter for Coherent= { > +impl debugfs::BinaryWriter for Cohere= nt { > fn write_to_slice( > &self, > writer: &mut UserSliceWriter,