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Revert "FROMLIST: rust: miscdevice: add mmap support"

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This reverts commit 88a4dfa30b.

Bug: 429146594
Change-Id: Ia75f9f7f9706971fe47e6ab74a8f0009876396af
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
This commit is contained in:
Alice Ryhl
2025-07-02 12:15:47 +00:00
parent b7f54dd23b
commit 6de3ace5b5
1 changed files with 0 additions and 44 deletions
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44
rust/kernel/miscdevice.rs
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@@ -14,7 +14,6 @@ use crate::{
error::{to_result, Error, Result, VTABLE_DEFAULT_ERROR},
ffi::{c_int, c_long, c_uint, c_ulong, c_void},
fs::{File, LocalFile},
mm::virt::VmAreaNew,
prelude::*,
seq_file::SeqFile,
str::CStr,
@@ -124,22 +123,6 @@ pub trait MiscDevice: Sized {
drop(device);
}
/// Handle for mmap.
///
/// This function is invoked when a user space process invokes the `mmap` system call on
/// `file`. The function is a callback that is part of the VMA initializer. The kernel will do
/// initial setup of the VMA before calling this function. The function can then interact with
/// the VMA initialization by calling methods of `vma`. If the function does not return an
/// error, the kernel will complete initialization of the VMA according to the properties of
/// `vma`.
fn mmap(
_device: <Self::Ptr as ForeignOwnable>::Borrowed<'_>,
_file: &File,
_vma: &VmAreaNew,
) -> Result {
kernel::build_error!(VTABLE_DEFAULT_ERROR)
}
/// Seeks this miscdevice.
fn llseek(
_device: <Self::Ptr as ForeignOwnable>::Borrowed<'_>,
@@ -286,7 +269,6 @@ const fn create_vtable<T: MiscDevice>() -> &'static bindings::file_operations {
const VTABLE: bindings::file_operations = bindings::file_operations {
open: Some(fops_open::<T>),
release: Some(fops_release::<T>),
mmap: maybe_fn(T::HAS_MMAP, fops_mmap::<T>),
llseek: maybe_fn(T::HAS_LLSEEK, fops_llseek::<T>),
read_iter: maybe_fn(T::HAS_READ_ITER, fops_read_iter::<T>),
write_iter: maybe_fn(T::HAS_WRITE_ITER, fops_write_iter::<T>),
@@ -371,32 +353,6 @@ unsafe extern "C" fn fops_release<T: MiscDevice>(
0
}
/// # Safety
///
/// `file` must be a valid file that is associated with a `MiscDeviceRegistration<T>`.
/// `vma` must be a vma that is currently being mmap'ed with this file.
unsafe extern "C" fn fops_mmap<T: MiscDevice>(
file: *mut bindings::file,
vma: *mut bindings::vm_area_struct,
) -> c_int {
// SAFETY: The mmap call of a file can access the private data.
let private = unsafe { (*file).private_data };
// SAFETY: This is a Rust Miscdevice, so we call `into_foreign` in `open` and `from_foreign` in
// `release`, and `fops_mmap` is guaranteed to be called between those two operations.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
// SAFETY: The caller provides a vma that is undergoing initial VMA setup.
let area = unsafe { VmAreaNew::from_raw(vma) };
// SAFETY:
// * The file is valid for the duration of this call.
// * There is no active fdget_pos region on the file on this thread.
let file = unsafe { File::from_raw_file(file) };
match T::mmap(device, file, area) {
Ok(()) => 0,
Err(err) => err.to_errno() as c_int,
}
}
/// # Safety
///
/// `file` must be a valid file that is associated with a `MiscDeviceRegistration<T>`.