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Date: Sat, 28 Oct 2023 00:36:35 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>,
	FUJITA Tomonori <fujita.tomonori@gmail.com>, netdev@vger.kernel.org,
	rust-for-linux@vger.kernel.org, tmgross@umich.edu,
	miguel.ojeda.sandonis@gmail.com, wedsonaf@gmail.com
Subject: Re: [PATCH net-next v7 1/5] rust: core abstractions for network PHY
 drivers
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References: <20231026001050.1720612-1-fujita.tomonori@gmail.com>
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 <ZTwWse0COE3w6_US@boqun-archlinux>
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In-Reply-To: <ZTw3_--yDkJ9ZwIP@boqun-archlinux>

> Hmm... but does it mean even `set_speed()` has the similar issue?
> 
> 	let phydev: *mut phy_device = self.0.get();
> 	unsafe { (*phydev).speed = ...; }
> 
> The `(*phydev)` creates a `&mut` IIUC. So we need the following maybe?
> 
> 	let phydev: *mut phy_device = self.0.get();
> 	unsafe { *addr_mut_of!((*phydev).speed) = ...; }
> 
> because at least from phylib core guarantee, we know no one accessing
> `speed` in the same time. However, yes, bit fields are tricky...

Speed is not a bitfield. Its a plain boring int. link is however a bit
field.

	Andrew