These will be used for the read_iter() and write_iter() callbacks, which
are now the preferred back-ends for when a user operates on a char device
with read() and write() respectively.
Co-developed-by: Lee Jones <lee@xxxxxxxxxx>
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
Reviewed-by: Andreas Hindborg <a.hindborg@xxxxxxxxxx>
Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
---
rust/kernel/miscdevice.rs | 63 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs
index 6373fe183b2748162988b45d7ed8f563045d3b4d..35630fc638751c416d009fcf0c0ffdf0a4da1218 100644
--- a/rust/kernel/miscdevice.rs
+++ b/rust/kernel/miscdevice.rs
@@ -13,7 +13,8 @@
device::Device,
error::{to_result, Error, Result, VTABLE_DEFAULT_ERROR},
ffi::{c_int, c_long, c_uint, c_ulong},
- fs::File,
+ fs::{File, Kiocb},
+ iov::{IovIterDest, IovIterSource},
mm::virt::VmaNew,
prelude::*,
seq_file::SeqFile,
@@ -141,6 +142,16 @@ fn mmap(
build_error!(VTABLE_DEFAULT_ERROR)
}
+ /// Read from this miscdevice.
+ fn read_iter(_kiocb: Kiocb<'_, Self::Ptr>, _iov: &mut IovIterDest<'_>) -> Result<usize> {
+ build_error!(VTABLE_DEFAULT_ERROR)
+ }
+
+ /// Write to this miscdevice.
+ fn write_iter(_kiocb: Kiocb<'_, Self::Ptr>, _iov: &mut IovIterSource<'_>) -> Result<usize> {
+ build_error!(VTABLE_DEFAULT_ERROR)
+ }
+
/// Handler for ioctls.
///
/// The `cmd` argument is usually manipulated using the utilities in [`kernel::ioctl`].
@@ -245,6 +256,46 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
0
}
+ /// # Safety
+ ///
+ /// `kiocb` must be correspond to a valid file that is associated with a
+ /// `MiscDeviceRegistration<T>`. `iter` must be a valid `struct iov_iter` for writing.
+ unsafe extern "C" fn read_iter(
+ kiocb: *mut bindings::kiocb,
+ iter: *mut bindings::iov_iter,
+ ) -> isize {
+ // SAFETY: The caller provides a valid `struct kiocb` associated with a
+ // `MiscDeviceRegistration<T>` file.
+ let kiocb = unsafe { Kiocb::from_raw(kiocb) };
+ // SAFETY: This is a valid `struct iov_iter` for writing.
+ let iov = unsafe { IovIterDest::from_raw(iter) };
+
+ match T::read_iter(kiocb, iov) {
+ Ok(res) => res as isize,
+ Err(err) => err.to_errno() as isize,
+ }
+ }
+
+ /// # Safety
+ ///
+ /// `kiocb` must be correspond to a valid file that is associated with a
+ /// `MiscDeviceRegistration<T>`. `iter` must be a valid `struct iov_iter` for writing.
+ unsafe extern "C" fn write_iter(
+ kiocb: *mut bindings::kiocb,
+ iter: *mut bindings::iov_iter,
+ ) -> isize {
+ // SAFETY: The caller provides a valid `struct kiocb` associated with a
+ // `MiscDeviceRegistration<T>` file.
+ let kiocb = unsafe { Kiocb::from_raw(kiocb) };
+ // SAFETY: This is a valid `struct iov_iter` for reading.
+ let iov = unsafe { IovIterSource::from_raw(iter) };
+
+ match T::write_iter(kiocb, iov) {
+ Ok(res) => res as isize,
+ Err(err) => err.to_errno() as isize,
+ }
+ }
+
/// # Safety
///
/// `file` must be a valid file that is associated with a `MiscDeviceRegistration<T>`.
@@ -341,6 +392,16 @@ impl<T: MiscDevice> MiscdeviceVTable<T> {
open: Some(Self::open),
release: Some(Self::release),
mmap: if T::HAS_MMAP { Some(Self::mmap) } else { None },
+ read_iter: if T::HAS_READ_ITER {
+ Some(Self::read_iter)
+ } else {
+ None
+ },
+ write_iter: if T::HAS_WRITE_ITER {
+ Some(Self::write_iter)
+ } else {
+ None
+ },
unlocked_ioctl: if T::HAS_IOCTL {
Some(Self::ioctl)
} else {
--
2.51.0.rc2.233.g662b1ed5c5-goog
