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a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=1917; i=aliceryhl@google.com; h=from:subject:message-id; bh=oq9udGuCcSsMEvbqP89aogF1VgUZC37t/ErsD/OVHrw=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBn3B3NFeE1Ogr3RQZHN9/v7DaROFK5k4mpOMKCD 1Bd7vq5b1SJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCZ9wdzQAKCRAEWL7uWMY5 RgB6D/0WkW5RJz0jjMuXX3XTipgrz//n0nnWXy+rkrG5AGwSDuVf3M4Pio0sjmwpUUIw1uWFewq FCeIWWqhvI1k8xFxhXzkGXobRcV2V7agTcSuheKZwR5cIHu4zTBdu4ixma4xl+PrH9PpNptnnbx cjKzDQeS4Tuc6Cp2tdcsz9DG+Gpy38V0184/y2k3RFf8RCvWaFUN1FVNeSN53SI9QOVImcyL8CD 5P6MuQkgyaVRCDU3F9gQzJ79VDNbxCRPdKTHzoAGoW+9I4LQX0Up+qUORWONQNaZ4nT0nAKnY6B z5JcOXwELHaNMqCoiy7xPr85LYgJ4DHuqXp+WOJP4aBgwoUlVA4bkSx9TpMf3BJmaYfrRTPpnpu Ji7jw+sjx+UddZ7X7J6lCfrJTYEm2QHQvAtvFh7bBTjI+aeMV9syMuii0aUXkgsxPCSP91Nh4xI uokdy/KAnkk1Shz4V6+Gr+870N9TQx414tLvmduVix5D9q2xYEvyxEaOgZduvIvhHBiW+8mYJ9W YbiX+p4ZII5fHHxZErqUrje8kXdgDeRRFIkuN8FJHWfsrRF3kCUwQphuQpbRlBCLm0MrrYD4bur bj7mHFHm1rNBaqvWJIwMV62lrKw4z/bsJlH1gpHzsl6uFalCYCpMKc4saFWoFaep/YQenO8dZmx v6y+Oy7M5/gyWVw== X-Mailer: b4 0.14.2 Message-ID: <20250320-vec-methods-v1-3-7dff5cf25fe8@google.com> Subject: [PATCH 3/5] rust: alloc: add Vec::push_within_capacity From: Alice Ryhl To: Danilo Krummrich Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Alice Ryhl Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable This introduces a new method called `push_within_capacity` for appending to a vector without attempting to allocate if the capacity is full. Rust Binder will use this in various places to safely push to a vector while holding a spinlock. The existing Vec::push method is reimplemented in terms of the new method. Signed-off-by: Alice Ryhl Reviewed-by: Benno Lossin --- rust/kernel/alloc/kvec.rs | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 9943358c70aa63f5ad7ed9782cb8879d7a80a8fb..df930ff0d0b85b8b03c9b7932a2= b31dfb62612ed 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -284,6 +284,31 @@ pub fn spare_capacity_mut(&mut self) -> &mut [MaybeUni= nit] { /// ``` pub fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError> { self.reserve(1, flags)?; + let err =3D self.push_within_capacity(v); + // SAFETY: The call to `reserve` was successful, so `push_within_c= apacity` cannot fail. + unsafe { err.unwrap_unchecked() }; + Ok(()) + } + + /// Appends an element to the back of the [`Vec`] instance. + /// + /// Fails if the vector does not have capacity for the new element. + /// + /// # Examples + /// + /// ``` + /// let mut v =3D KVec::with_capacity(10, GFP_KERNEL); + /// for i in 0..10 { + /// v.push_within_capacity(i).unwrap(); + /// } + /// + /// assert!(v.push_within_capacity(11).is_err()); + /// # Ok::<(), Error>(()) + /// ``` + pub fn push_within_capacity(&mut self, v: T) -> Result<(), T> { + if self.len() >=3D self.capacity() { + return Err(v); + } =20 // SAFETY: // - `self.len` is smaller than `self.capacity` and hence, the res= ulting pointer is --=20 2.49.0.rc1.451.g8f38331e32-goog