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Howlett" , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo Cc: Daniel Gomez , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=4023; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=ziAsziTOC+GzNf139Ut4jKaT94DhutbUW+Q40shocZ0=; b=owEBbQKS/ZANAwAKAeG4Gj55KGN3AcsmYgBphljnlh0PwhOjbdwrAoJpOnH1unnfNaF62jnVf OpMfNpflSuJAjMEAAEKAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaYZY5wAKCRDhuBo+eShj d8lxD/96tdOwjEygElTB5W6BwdRyLgvYB/hCTUV/zpbiLgUPQl0pzk+j00jlWUivFwhQBOnlwrE YEgUGsY/y5uzXaAiw5NXnitAZoS6ZGWv2tpbAHvUCwwc/flX1p5Uu6leUtXPY6T8t+ok4lz9DR1 fGSwg7Gb4f1ffmZkq62vlMR9FqECeE+RmhnAT3e9r2m86CSHMgXP5/qHqmzJlmSLxx+3YXqBR6U Yrh1rib85R+ov46tLBhvLSAKzrL6BSdNV8tklv3VD6n6gsCV7q7/JX3FgKFSw24OOX2x6sbc8oo zGsiXe2tpDo6CRpW9wavJsKgtq/VDBtvN7UohRxYDjmJXzRuYW88v4vMnUfPhOz5zgpYbbOEuZC M+vfJ29OIKm2qyjV2440+qdZP3PQFKHf4qOfOowsUnl/l6cBO2mj3GvbRXQ9I/1YcSj/Lt8mBIf hx9fybxfvq/KPIruXbehNTsdyXANogQmXTM5FNNbNLzYWLRarWRxU5cLHl38aMYDJLZwSfYQYlT fP5dvm4HKTSK0uw6wgVIg0dKjwug2PyccQwuqOtW71GIX20wNp89kFn3Dvh16L15xMTuxvxwjMd AltU2qTF9HFwtjnkMPV7R0bERe3P/+XCRDU64hmmiITp7fSgoqnSVu+poZABp+Ue1z5gi/tT4sH gUswhjAe8geVmNg== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 X-Rspam-User: X-Rspamd-Queue-Id: B67A5140004 X-Rspamd-Server: rspam07 X-Stat-Signature: rm5g3yk5a1k4wsx448pbfz7ghkww4jbo X-HE-Tag: 1770412301-576878 X-HE-Meta: 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 V5DWZIsq yeZP5pTBqpPMR3WOLUMKG9YVXUkC32X+HEPWY/vUgU4oFE/MfrakJBHW6BbGnt8tjLA+Ab6JWJRDjEJ9ovE/LTxv9Y3sG4jXD3QkaZJbNxuCF/KKDkLIOKCngLRS2OQkHMhiyzsBPF8zPuKbB7Jsw6Ps3p31Z4Cb/yW9Txa43Gc7klbV+hJrgNlq4q45TG4Duqbwgpx8mMyoWNn9pFi7uYGKQ1vTc+lEzRaiKGP9d10D2ENdSOkTyOFjZtxyc/oMJdmdJParC93cOmmWV76tC+OIpYogtpQLQ1lyZ8O/T7oKGU9FJ9eSQmcxMeXzLuop6VHkfXZpU650MmW0tQXmp2Ls+6ysefWyUTnhHu7cZYxviwi4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add methods to find the next element in an XArray starting from a given index. The methods return a tuple containing the index where the element was found and a reference to the element. The implementation uses the XArray state API via `xas_find` to avoid taking the rcu lock as an exclusive lock is already held by `Guard`. Signed-off-by: Andreas Hindborg --- rust/kernel/xarray.rs | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs index e654bf56dc97c..656ec897a0c41 100644 --- a/rust/kernel/xarray.rs +++ b/rust/kernel/xarray.rs @@ -251,6 +251,67 @@ pub fn get_mut(&mut self, index: usize) -> Option> { Some(unsafe { T::borrow_mut(ptr.as_ptr()) }) } + fn load_next(&self, index: usize) -> Option<(usize, NonNull)> { + XArrayState::new(self, index).load_next() + } + + /// Finds the next element starting from the given index. + /// + /// # Examples + /// + /// ``` + /// # use kernel::{prelude::*, xarray::{AllocKind, XArray}}; + /// let mut xa = KBox::pin_init(XArray::>::new(AllocKind::Alloc), GFP_KERNEL)?; + /// let mut guard = xa.lock(); + /// + /// guard.store(10, KBox::new(10u32, GFP_KERNEL)?, GFP_KERNEL)?; + /// guard.store(20, KBox::new(20u32, GFP_KERNEL)?, GFP_KERNEL)?; + /// + /// if let Some((found_index, value)) = guard.find_next(11) { + /// assert_eq!(found_index, 20); + /// assert_eq!(*value, 20); + /// } + /// + /// if let Some((found_index, value)) = guard.find_next(5) { + /// assert_eq!(found_index, 10); + /// assert_eq!(*value, 10); + /// } + /// + /// # Ok::<(), kernel::error::Error>(()) + /// ``` + pub fn find_next(&self, index: usize) -> Option<(usize, T::Borrowed<'_>)> { + self.load_next(index) + // SAFETY: `ptr` came from `T::into_foreign`. + .map(|(index, ptr)| (index, unsafe { T::borrow(ptr.as_ptr()) })) + } + + /// Finds the next element starting from the given index, returning a mutable reference. + /// + /// # Examples + /// + /// ``` + /// # use kernel::{prelude::*, xarray::{AllocKind, XArray}}; + /// let mut xa = KBox::pin_init(XArray::>::new(AllocKind::Alloc), GFP_KERNEL)?; + /// let mut guard = xa.lock(); + /// + /// guard.store(10, KBox::new(10u32, GFP_KERNEL)?, GFP_KERNEL)?; + /// guard.store(20, KBox::new(20u32, GFP_KERNEL)?, GFP_KERNEL)?; + /// + /// if let Some((found_index, mut_value)) = guard.find_next_mut(5) { + /// assert_eq!(found_index, 10); + /// *mut_value = 0x99; + /// } + /// + /// assert_eq!(guard.get(10).copied(), Some(0x99)); + /// + /// # Ok::<(), kernel::error::Error>(()) + /// ``` + pub fn find_next_mut(&mut self, index: usize) -> Option<(usize, T::BorrowedMut<'_>)> { + self.load_next(index) + // SAFETY: `ptr` came from `T::into_foreign`. + .map(move |(index, ptr)| (index, unsafe { T::borrow_mut(ptr.as_ptr()) })) + } + /// Removes and returns the element at the given index. pub fn remove(&mut self, index: usize) -> Option { // SAFETY: @@ -354,6 +415,13 @@ fn load(&mut self) -> Option> { let ptr = unsafe { bindings::xas_load(&raw mut self.state) }; NonNull::new(ptr.cast()) } + + fn load_next(&mut self) -> Option<(usize, NonNull)> { + // SAFETY: `self.state` is always valid by the type invariant of + // `XArrayState` and the we hold the xarray lock. + let ptr = unsafe { bindings::xas_find(&raw mut self.state, usize::MAX) }; + NonNull::new(ptr).map(|ptr| (self.state.xa_index, ptr)) + } } // SAFETY: `XArray` has no shared mutable state so it is `Send` iff `T` is `Send`. -- 2.51.2