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| -rw-r--r-- | rust/kernel/uaccess.rs | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs index a8fb4764185a..1409cb907015 100644 --- a/rust/kernel/uaccess.rs +++ b/rust/kernel/uaccess.rs @@ -287,6 +287,23 @@ impl UserSliceReader { self.read_raw(out) } + /// Reads raw data from the user slice into a kernel buffer partially. + /// + /// This is the same as [`Self::read_slice`] but considers the given `offset` into `out` and + /// truncates the read to the boundaries of `self` and `out`. + /// + /// On success, returns the number of bytes read. + pub fn read_slice_partial(&mut self, out: &mut [u8], offset: usize) -> Result<usize> { + let end = offset.saturating_add(self.len()).min(out.len()); + + let Some(dst) = out.get_mut(offset..end) else { + return Ok(0); + }; + + self.read_slice(dst)?; + Ok(dst.len()) + } + /// Reads a value of the specified type. /// /// Fails with [`EFAULT`] if the read happens on a bad address, or if the read goes out of |