| Message ID | 20241210-miscdevice-file-param-v3-3-b2a79b666dc5@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Additional miscdevice fops parameters | expand |
On Tue, 10 Dec 2024, Alice Ryhl wrote: > From: Lee Jones <lee@kernel.org> > > There are situations where a pointer to a `struct device` will become > necessary (e.g. for calling into dev_*() functions). This accessor > allows callers to pull this out from the `struct miscdevice`. > > Signed-off-by: Lee Jones <lee@kernel.org> > Signed-off-by: Alice Ryhl <aliceryhl@google.com> > --- > rust/kernel/miscdevice.rs | 11 +++++++++++ > 1 file changed, 11 insertions(+) This might be superfluous, but: Tested-by: Lee Jones <lee@kernel.org>
diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 75a9d26c8001..20895e809607 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -10,6 +10,7 @@ use crate::{ bindings, + device::Device, error::{to_result, Error, Result, VTABLE_DEFAULT_ERROR}, fs::File, prelude::*, @@ -85,6 +86,16 @@ pub fn register(opts: MiscDeviceOptions) -> impl PinInit<Self, Error> { pub fn as_raw(&self) -> *mut bindings::miscdevice { self.inner.get() } + + /// Access the `this_device` field. + pub fn device(&self) -> &Device { + // SAFETY: This can only be called after a successful register(), which always + // initialises `this_device` with a valid device. Furthermore, the signature of this + // function tells the borrow-checker that the `&Device` reference must not outlive the + // `&MiscDeviceRegistration<T>` used to obtain it, so the last use of the reference must be + // before the underlying `struct miscdevice` is destroyed. + unsafe { Device::as_ref((*self.as_raw()).this_device) } + } } #[pinned_drop]