diff options
Diffstat (limited to 'rust/kernel/error.rs')
| -rw-r--r-- | rust/kernel/error.rs | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 935787c2a91c..decceb6ae855 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -452,6 +452,9 @@ pub fn to_result(err: crate::ffi::c_int) -> Result { /// for errors. This function performs the check and converts the "error pointer" /// to a normal pointer in an idiomatic fashion. /// +/// Note that a `NULL` pointer is not considered an error pointer, and is returned +/// as-is, wrapped in [`Ok`]. +/// /// # Examples /// /// ```ignore @@ -466,6 +469,34 @@ pub fn to_result(err: crate::ffi::c_int) -> Result { /// from_err_ptr(unsafe { bindings::devm_platform_ioremap_resource(pdev.to_ptr(), index) }) /// } /// ``` +/// +/// ``` +/// # use kernel::error::from_err_ptr; +/// # mod bindings { +/// # #![expect(clippy::missing_safety_doc)] +/// # use kernel::prelude::*; +/// # pub(super) unsafe fn einval_err_ptr() -> *mut kernel::ffi::c_void { +/// # EINVAL.to_ptr() +/// # } +/// # pub(super) unsafe fn null_ptr() -> *mut kernel::ffi::c_void { +/// # core::ptr::null_mut() +/// # } +/// # pub(super) unsafe fn non_null_ptr() -> *mut kernel::ffi::c_void { +/// # 0x1234 as *mut kernel::ffi::c_void +/// # } +/// # } +/// // SAFETY: ... +/// let einval_err = from_err_ptr(unsafe { bindings::einval_err_ptr() }); +/// assert_eq!(einval_err, Err(EINVAL)); +/// +/// // SAFETY: ... +/// let null_ok = from_err_ptr(unsafe { bindings::null_ptr() }); +/// assert_eq!(null_ok, Ok(core::ptr::null_mut())); +/// +/// // SAFETY: ... +/// let non_null = from_err_ptr(unsafe { bindings::non_null_ptr() }).unwrap(); +/// assert_ne!(non_null, core::ptr::null_mut()); +/// ``` pub fn from_err_ptr<T>(ptr: *mut T) -> Result<*mut T> { // CAST: Casting a pointer to `*const crate::ffi::c_void` is always valid. let const_ptr: *const crate::ffi::c_void = ptr.cast(); |