rust: uaccess: generalize userSliceReader to support any Vec

The UserSliceReader::read_all function is currently restricted to use
only Vec with the kmalloc allocator. However, there is no reason for
this limitation.

This patch generalizes the function to accept any Vec regardless of the
allocator used.

There's a use-case for a KVVec in Binder to avoid maximum sizes for a
certain array.

Link: https://github.com/Rust-for-Linux/linux/issues/1136
Signed-off-by: Filipe Xavier <felipeaggger@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250107-gen-userslice-readall-alloc-v2-1-d7fe4d19241a@gmail.com
[ Reflowed and slightly reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs
index cc044924867b89f6116c7f9ec216d8cea2b3f8d7..719b0a48ff5550acc19f2e607c0a09f818145def 100644 (file)
--- a/rust/kernel/uaccess.rs
+++ b/rust/kernel/uaccess.rs
@@ -5,7 +5,7 @@
 //! C header: [`include/linux/uaccess.h`](srctree/include/linux/uaccess.h)
 
 use crate::{
-    alloc::Flags,
+    alloc::{Allocator, Flags},
     bindings,
     error::Result,
     ffi::c_void,
@@ -127,7 +127,7 @@ impl UserSlice {
     /// Reads the entirety of the user slice, appending it to the end of the provided buffer.
     ///
     /// Fails with [`EFAULT`] if the read happens on a bad address.
-    pub fn read_all(self, buf: &mut KVec<u8>, flags: Flags) -> Result {
+    pub fn read_all<A: Allocator>(self, buf: &mut Vec<u8, A>, flags: Flags) -> Result {
         self.reader().read_all(buf, flags)
     }
 
@@ -281,7 +281,7 @@ impl UserSliceReader {
     /// Reads the entirety of the user slice, appending it to the end of the provided buffer.
     ///
     /// Fails with [`EFAULT`] if the read happens on a bad address.
-    pub fn read_all(mut self, buf: &mut KVec<u8>, flags: Flags) -> Result {
+    pub fn read_all<A: Allocator>(mut self, buf: &mut Vec<u8, A>, flags: Flags) -> Result {
         let len = self.length;
         buf.reserve(len, flags)?;