From: "Qingsong Chen" <changxian.cqs@antgroup.com>
To: linux-kernel@vger.kernel.org
Cc: 田洪亮 <tate.thl@antgroup.com>,
"Qingsong Chen" <changxian.cqs@antgroup.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Wedson Almeida Filho" <wedsonaf@gmail.com>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <benno.lossin@proton.me>,
rust-for-linux@vger.kernel.org
Subject: [PATCH v2 2/3] rust: kernel: implement iterators for ScatterList
Date: Fri, 02 Jun 2023 18:18:18 +0800 [thread overview]
Message-ID: <20230602101819.2134194-3-changxian.cqs@antgroup.com> (raw)
In-Reply-To: <20230602101819.2134194-1-changxian.cqs@antgroup.com>
ScatterList could be transmuted from raw pointers of a valid
`sg_table`. Then we can use those iterators to access the
following normal entries.
Signed-off-by: Qingsong Chen <changxian.cqs@antgroup.com>
---
rust/kernel/scatterlist.rs | 50 ++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/rust/kernel/scatterlist.rs b/rust/kernel/scatterlist.rs
index 8d6a34afb191..292fcb63a329 100644
--- a/rust/kernel/scatterlist.rs
+++ b/rust/kernel/scatterlist.rs
@@ -277,4 +277,54 @@ impl ScatterList<'_> {
// SAFETY: By the type invariant, we know that `self.opaque` is valid.
unsafe { bindings::sg_nents(self.opaque.get()) as _ }
}
+
+ /// Get an iterator for immutable references.
+ pub fn iter(&self) -> Iter<'_> {
+ Iter(ScatterList::as_ref(self.opaque.get()))
+ }
+
+ /// Get an iterator for mutable references.
+ pub fn iter_mut(&mut self) -> IterMut<'_> {
+ IterMut(ScatterList::as_mut(self.opaque.get()))
+ }
+}
+
+/// An iterator that yields [`Pin<&ScatterList>`].
+///
+/// Only iterate normal scatterlist entries, chainable entry will be skipped.
+pub struct Iter<'a>(Option<Pin<&'a ScatterList<'a>>>);
+
+impl<'a> Iterator for Iter<'a> {
+ type Item = Pin<&'a ScatterList<'a>>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.0.is_none() {
+ return None;
+ }
+ let ptr = self.0.as_ref().unwrap().opaque.get();
+ // SAFETY: `ptr` is from `self.opaque`, it is valid by the type invariant.
+ let next = unsafe { bindings::sg_next(ptr) };
+ self.0 = ScatterList::as_ref(next);
+ ScatterList::as_ref(ptr)
+ }
+}
+
+/// An iterator that yields [`Pin<&mut ScatterList>`].
+///
+/// Only iterate normal scatterlist entries, chainable entry will be skipped.
+pub struct IterMut<'a>(Option<Pin<&'a mut ScatterList<'a>>>);
+
+impl<'a> Iterator for IterMut<'a> {
+ type Item = Pin<&'a mut ScatterList<'a>>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.0.is_none() {
+ return None;
+ }
+ let ptr = self.0.as_ref().unwrap().opaque.get();
+ // SAFETY: `ptr` is from `self.opaque`, it is valid by the type invariant.
+ let next = unsafe { bindings::sg_next(ptr) };
+ self.0 = ScatterList::as_mut(next);
+ ScatterList::as_mut(ptr)
+ }
}
--
2.40.1
next prev parent reply other threads:[~2023-06-02 10:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 10:18 [PATCH v2 0/3] Rust scatterlist abstractions Qingsong Chen
2023-06-02 10:18 ` [PATCH v2 1/3] rust: kernel: add ScatterList abstraction Qingsong Chen
2023-06-02 19:54 ` Martin Rodriguez Reboredo
2023-06-05 8:12 ` Qingsong Chen
2023-06-05 11:36 ` Miguel Ojeda
2023-06-05 15:26 ` Boqun Feng
2023-06-06 7:01 ` Qingsong Chen
2023-06-07 17:18 ` Boqun Feng
2023-06-07 18:42 ` Gary Guo
2023-06-07 19:40 ` Boqun Feng
2023-06-02 10:18 ` Qingsong Chen [this message]
2023-06-02 19:59 ` [PATCH v2 2/3] rust: kernel: implement iterators for ScatterList Martin Rodriguez Reboredo
2023-06-02 10:18 ` [PATCH v2 3/3] rust: kernel: add SgTable abstraction Qingsong Chen
2023-06-02 20:47 ` Martin Rodriguez Reboredo
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