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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/ZANAwAKAeG4Gj55KGN3AcsmYgBpifFb+WmuAcVCQgvEERtgQ/qOeo8uSZnzezgaA +8xw4pzCZmJAjMEAAEKAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaYnxWwAKCRDhuBo+eShj d4DhD/9wCbNkHivRJZdlO3SafsRrM1Jz/9FULnqXMomuVFOyx4R8DA04Vr1ryCJ05XWJyhekl4Z G5vVUO8k7DN6sWkUJEoaVgwaA+cAdqR6vETzYtNa8CNUYFrBH7F7IuNhOehoVVMRvTViVrfBiHn Omr9wEVK9MuXNHJWTwnGsLCVyGGgpqzlbwlL0r9HilBKQ2sJM4Ms/9G2LmyjDh8PExLTNxDxl/f n6TZWTg20i8MW5Ah6w0oDUrXSzduI0NuQTki4WxhKTtaRzvofUZuAztzg0lyT49muXqhhqMLBas JGmniyaN9E+oneAYw1iXPAZGQ6BSioVn5m6JPVB/FdUc3w7+4Yh6WG//E9j6bJHQn+Nwh0Csc/W OOVLjAamz/vGabbs7W8G+tWP3rJhq01jdtXaAONXcE/S2CT5B3exP5+ymlnemY9MqAVktGE2mvg 5OTbekmZVE37vqI9e9/9CjVsFw6dyC0espFckCrEbgE0zh6CpPt5IEaSGPF4sBhm9WyLmQsZCpw GdbWMoq0K9av8QM75C7DvHme4QBQJWpvAlBhaRNX4F+G2MzpBZZTMGes/bcWRSW+igfHxyum7j5 /uriDRU6pIaS6gsbLqj+fjWHKwrsxdFBlP9Ix+nyDnMigT+SRQZm2PlAuEwSok+Ws/jmFTFBW/m GYLsZBX4KKU+Zrg== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 919011A000C X-Stat-Signature: tqx9f7prjzupjtsq3u468w3hpt8c5h63 X-HE-Tag: 1770647994-676667 X-HE-Meta: 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 ogK2JbNw kgjEdCjT81DSrRGW4luofJFn+990kYuYk4RPlUuH6BYlM2aU= 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