[PATCH 44/80] rust: serde: add support for deserializing Vec with kernel_alloc feature

From: Ariel Miculas <amiculas@cisco.com>
To: rust-for-linux@vger.kernel.org
Cc: Ariel Miculas <amiculas@cisco.com>
Subject: [PATCH 44/80] rust: serde: add support for deserializing Vec with kernel_alloc feature
Date: Fri,  9 Jun 2023 09:30:42 +0300	[thread overview]
Message-ID: <20230609063118.24852-45-amiculas@cisco.com> (raw)
In-Reply-To: <20230609063118.24852-1-amiculas@cisco.com>

Signed-off-by: Ariel Miculas <amiculas@cisco.com>
---
 rust/Makefile                   |  4 +++-
 rust/serde/de/impls.rs          | 19 +++++++++++++++++--
 rust/serde/lib.rs               |  2 +-
 rust/serde/private/size_hint.rs |  2 +-
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 0b67547d8007..c9feb8e1afe1 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -120,7 +120,9 @@ serde-skip_flags := \
 
 serde-flags := \
     -Amissing_docs \
-    --cfg no_fp_fmt_parse
+    --cfg no_fp_fmt_parse \
+    --cfg 'feature="kernel_alloc"' \
+    --extern alloc
 
 serde_cbor-skip_flags := \
     --edition=2021 \
diff --git a/rust/serde/de/impls.rs b/rust/serde/de/impls.rs
index 9377f5eee650..6b860b2d9450 100644
--- a/rust/serde/de/impls.rs
+++ b/rust/serde/de/impls.rs
@@ -11,9 +11,12 @@
 
 use seed::InPlaceSeed;
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(any(feature = "std", feature = "alloc", feature = "kernel_alloc"))]
 use __private::size_hint;
 
+#[cfg(feature = "kernel_alloc")]
+use alloc::vec::Vec;
+
 ////////////////////////////////////////////////////////////////////////////////
 
 struct UnitVisitor;
@@ -1012,7 +1015,7 @@ fn nop_reserve<T>(_seq: T, _n: usize) {}
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(any(feature = "std", feature = "alloc", feature = "kernel_alloc"))]
 impl<'de, T> Deserialize<'de> for Vec<T>
 where
     T: Deserialize<'de>,
@@ -1039,10 +1042,16 @@ fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
             where
                 A: SeqAccess<'de>,
             {
+                #[cfg(not(feature = "kernel_alloc"))]
                 let mut values = Vec::with_capacity(size_hint::cautious(seq.size_hint()));
+                #[cfg(feature = "kernel_alloc")]
+                let mut values = Vec::try_with_capacity(size_hint::cautious(seq.size_hint())).unwrap();
 
                 while let Some(value) = try!(seq.next_element()) {
+                    #[cfg(not(feature = "kernel_alloc"))]
                     values.push(value);
+                    #[cfg(feature = "kernel_alloc")]
+                    values.try_push(value).unwrap();
                 }
 
                 Ok(values)
@@ -1077,7 +1086,10 @@ fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
             {
                 let hint = size_hint::cautious(seq.size_hint());
                 if let Some(additional) = hint.checked_sub(self.0.len()) {
+                    #[cfg(not(feature = "kernel_alloc"))]
                     self.0.reserve(additional);
+                    #[cfg(feature = "kernel_alloc")]
+                    self.0.try_reserve(additional).unwrap();
                 }
 
                 for i in 0..self.0.len() {
@@ -1092,7 +1104,10 @@ fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
                 }
 
                 while let Some(value) = try!(seq.next_element()) {
+                    #[cfg(not(feature = "kernel_alloc"))]
                     self.0.push(value);
+                    #[cfg(feature = "kernel_alloc")]
+                    self.0.try_push(value).unwrap();
                 }
 
                 Ok(())
diff --git a/rust/serde/lib.rs b/rust/serde/lib.rs
index c3694fef3321..bfc845e98075 100644
--- a/rust/serde/lib.rs
+++ b/rust/serde/lib.rs
@@ -156,7 +156,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "alloc")]
+#[cfg(any(feature = "alloc", feature = "kernel_alloc"))]
 extern crate alloc;
 
 /// A facade around all the types we need from the `std`, `core`, and `alloc`
diff --git a/rust/serde/private/size_hint.rs b/rust/serde/private/size_hint.rs
index f050fca59deb..ac3c9394e7d3 100644
--- a/rust/serde/private/size_hint.rs
+++ b/rust/serde/private/size_hint.rs
@@ -9,7 +9,7 @@ pub fn from_bounds<I>(iter: &I) -> Option<usize>
     helper(iter.size_hint())
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(any(feature = "std", feature = "alloc", feature = "kernel_alloc"))]
 #[inline]
 pub fn cautious(hint: Option<usize>) -> usize {
     cmp::min(hint.unwrap_or(0), 4096)
-- 
2.40.1

