[PATCH 0/3] Rust 1.73.0 upgrade

[PATCH 0/3] Rust 1.73.0 upgrade

[Miguel Ojeda]

This is the next upgrade to the Rust toolchain since the initial Rust
merge, from 1.72.1 to 1.73.0 (i.e. the latest, released today).

Please see the main patch message for a long explanation of the upgrade,
the policy for future upgrades and some indications on how to easily
review this.

The series is based on `rust-next`.

Miguel Ojeda (3):
  rust: task: remove redundant explicit link
  rust: print: use explicit link in documentation
  rust: upgrade to Rust 1.73.0

 Documentation/process/changes.rst |  2 +-
 rust/alloc/alloc.rs               | 22 --------------
 rust/alloc/boxed.rs               | 48 ++++++++++++++++++++-----------
 rust/alloc/lib.rs                 |  5 ++--
 rust/alloc/raw_vec.rs             | 30 ++++++++++++-------
 rust/alloc/vec/mod.rs             |  4 +--
 rust/alloc/vec/spec_extend.rs     |  8 +++---
 rust/compiler_builtins.rs         |  1 +
 rust/kernel/print.rs              |  1 +
 rust/kernel/task.rs               |  2 +-
 scripts/min-tool-version.sh       |  2 +-
 11 files changed, 65 insertions(+), 60 deletions(-)


base-commit: b2516f7af9d238ebc391bdbdae01ac9528f1109e
--
2.42.0

[PATCH 1/3] rust: task: remove redundant explicit link

[Miguel Ojeda]

Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
links with its new lint `redundant_explicit_links` [1]:

    error: redundant explicit link target
      --> rust/kernel/task.rs:85:21
       |
    85 |     /// [`current`](crate::current) macro because it is safe.
       |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
       |          |
       |          because label contains path that resolves to same destination
       |
       = note: when a link's destination is not specified,
               the label is used to resolve intra-doc links
       = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
    help: remove explicit link target
       |
    85 |     /// [`current`] macro because it is safe.

In order to avoid the warning in the compiler upgrade commit,
make it an intra-doc link as the tool suggests.

Link: https://github.com/rust-lang/rust/pull/113167 [1]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/kernel/task.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
index 7eda15e5f1b3..b2299bc7ac1f 100644
--- a/rust/kernel/task.rs
+++ b/rust/kernel/task.rs
@@ -82,7 +82,7 @@ impl Task {
     /// Returns a task reference for the currently executing task/thread.
     ///
     /// The recommended way to get the current task/thread is to use the
-    /// [`current`](crate::current) macro because it is safe.
+    /// [`current`] macro because it is safe.
     ///
     /// # Safety
     ///
-- 
2.42.0

Re: [PATCH 1/3] rust: task: remove redundant explicit link

[Martin Rodriguez Reboredo]

On 10/5/23 18:05, Miguel Ojeda wrote:
> Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
> links with its new lint `redundant_explicit_links` [1]:
> 
>      error: redundant explicit link target
>        --> rust/kernel/task.rs:85:21
>         |
>      85 |     /// [`current`](crate::current) macro because it is safe.
>         |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
>         |          |
>         |          because label contains path that resolves to same destination
>         |
>         = note: when a link's destination is not specified,
>                 the label is used to resolve intra-doc links
>         = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
>      help: remove explicit link target
>         |
>      85 |     /// [`current`] macro because it is safe.
> 
> In order to avoid the warning in the compiler upgrade commit,
> make it an intra-doc link as the tool suggests.
> 
> Link: https://github.com/rust-lang/rust/pull/113167 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> [...]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

Re: [PATCH 1/3] rust: task: remove redundant explicit link

[Finn Behrens]

On 5 Oct 2023, at 23:05, Miguel Ojeda wrote:

> Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
> links with its new lint `redundant_explicit_links` [1]:
>
>     error: redundant explicit link target
>       --> rust/kernel/task.rs:85:21
>        |
>     85 |     /// [`current`](crate::current) macro because it is safe.
>        |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
>        |          |
>        |          because label contains path that resolves to same destination
>        |
>        = note: when a link's destination is not specified,
>                the label is used to resolve intra-doc links
>        = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
>     help: remove explicit link target
>        |
>     85 |     /// [`current`] macro because it is safe.
>
> In order to avoid the warning in the compiler upgrade commit,
> make it an intra-doc link as the tool suggests.
>
> Link: https://github.com/rust-lang/rust/pull/113167 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---

Reviewed-by: Finn Behrens <me@kloenk.dev>

Re: [PATCH 1/3] rust: task: remove redundant explicit link

[Alice Ryhl]

On Thu, Oct 5, 2023 at 11:06 PM Miguel Ojeda <ojeda@kernel.org> wrote:
> Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
> links with its new lint `redundant_explicit_links` [1]:
>
>     error: redundant explicit link target
>       --> rust/kernel/task.rs:85:21
>        |
>     85 |     /// [`current`](crate::current) macro because it is safe.
>        |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
>        |          |
>        |          because label contains path that resolves to same destination
>        |
>        = note: when a link's destination is not specified,
>                the label is used to resolve intra-doc links
>        = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
>     help: remove explicit link target
>        |
>     85 |     /// [`current`] macro because it is safe.
>
> In order to avoid the warning in the compiler upgrade commit,
> make it an intra-doc link as the tool suggests.
>
> Link: https://github.com/rust-lang/rust/pull/113167 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH 1/3] rust: task: remove redundant explicit link

[Vincenzo Palazzo]

> Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
> links with its new lint `redundant_explicit_links` [1]:
>
>     error: redundant explicit link target
>       --> rust/kernel/task.rs:85:21
>        |
>     85 |     /// [`current`](crate::current) macro because it is safe.
>        |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
>        |          |
>        |          because label contains path that resolves to same destination
>        |
>        = note: when a link's destination is not specified,
>                the label is used to resolve intra-doc links
>        = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
>     help: remove explicit link target
>        |
>     85 |     /// [`current`] macro because it is safe.
>
> In order to avoid the warning in the compiler upgrade commit,
> make it an intra-doc link as the tool suggests.
>
> Link: https://github.com/rust-lang/rust/pull/113167 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

[PATCH 2/3] rust: print: use explicit link in documentation

[Miguel Ojeda]

The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
link for `pr_info!`:

    error: unresolved link to `pr_info`
       --> rust/kernel/print.rs:395:63
        |
    395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
        |                                                               ^^^^^^^^ no item named `pr_info` in scope
        |
        = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

Thus do so to avoid a broken link while upgrading.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/kernel/print.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
index 8009184bf6d7..f48926e3e9fe 100644
--- a/rust/kernel/print.rs
+++ b/rust/kernel/print.rs
@@ -399,6 +399,7 @@ macro_rules! pr_debug (
 /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
 /// `alloc::format!` for information about the formatting syntax.
 ///
+/// [`pr_info!`]: crate::pr_info!
 /// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont
 /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
 ///
-- 
2.42.0

Re: [PATCH 2/3] rust: print: use explicit link in documentation

[Martin Rodriguez Reboredo]

On 10/5/23 18:05, Miguel Ojeda wrote:
> The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
> link for `pr_info!`:
> 
>      error: unresolved link to `pr_info`
>         --> rust/kernel/print.rs:395:63
>          |
>      395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
>          |                                                               ^^^^^^^^ no item named `pr_info` in scope
>          |
>          = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
>          = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
> 
> Thus do so to avoid a broken link while upgrading.
> 
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> [...]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

Re: [PATCH 2/3] rust: print: use explicit link in documentation

[Finn Behrens]

On 5 Oct 2023, at 23:05, Miguel Ojeda wrote:

> The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
> link for `pr_info!`:
>
>     error: unresolved link to `pr_info`
>        --> rust/kernel/print.rs:395:63
>         |
>     395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
>         |                                                               ^^^^^^^^ no item named `pr_info` in scope
>         |
>         = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
>         = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
>
> Thus do so to avoid a broken link while upgrading.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---

Reviewed-by: Finn Behrens <me@kloenk.dev>

Re: [PATCH 2/3] rust: print: use explicit link in documentation

[Alice Ryhl]

On Thu, Oct 5, 2023 at 11:06 PM Miguel Ojeda <ojeda@kernel.org> wrote:
> The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
> link for `pr_info!`:
>
>     error: unresolved link to `pr_info`
>        --> rust/kernel/print.rs:395:63
>         |
>     395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
>         |                                                               ^^^^^^^^ no item named `pr_info` in scope
>         |
>         = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
>         = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
>
> Thus do so to avoid a broken link while upgrading.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH 2/3] rust: print: use explicit link in documentation

[Vincenzo Palazzo]

> The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
> link for `pr_info!`:
>
>     error: unresolved link to `pr_info`
>        --> rust/kernel/print.rs:395:63
>         |
>     395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
>         |                                                               ^^^^^^^^ no item named `pr_info` in scope
>         |
>         = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
>         = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
>
> Thus do so to avoid a broken link while upgrading.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

[PATCH 3/3] rust: upgrade to Rust 1.73.0

[Miguel Ojeda]

This is the next upgrade to the Rust toolchain, from 1.72.1 to 1.73.0
(i.e. the latest) [1].

See the upgrade policy [2] and the comments on the first upgrade in
commit 3ed03f4da06e ("rust: upgrade to Rust 1.68.2").

# Unstable features

No unstable features (that we use) were stabilized.

Therefore, the only unstable feature allowed to be used outside
the `kernel` crate is still `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [3] for details.

# Required changes

For the upgrade, the following changes are required:

  - Allow `internal_features` for `feature(compiler_builtins)` since
    now Rust warns about using internal compiler and standard library
    features (similar to how it also warns about incomplete ones) [4].

  - A cleanup for a documentation link thanks to a new `rustdoc` lint.
    See previous commits for details.

  - A need to make an intra-doc link to a macro explicit, due to a
    change in behavior in `rustdoc`. See previous commits for details.

# `alloc` upgrade and reviewing

The vast majority of changes are due to our `alloc` fork being upgraded
at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1730-2023-10-05 [1]
Link: https://rust-for-linux.com/rust-version-policy [2]
Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
Link: https://github.com/rust-lang/compiler-team/issues/596 [4]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 Documentation/process/changes.rst |  2 +-
 rust/alloc/alloc.rs               | 22 --------------
 rust/alloc/boxed.rs               | 48 ++++++++++++++++++++-----------
 rust/alloc/lib.rs                 |  5 ++--
 rust/alloc/raw_vec.rs             | 30 ++++++++++++-------
 rust/alloc/vec/mod.rs             |  4 +--
 rust/alloc/vec/spec_extend.rs     |  8 +++---
 rust/compiler_builtins.rs         |  1 +
 scripts/min-tool-version.sh       |  2 +-
 9 files changed, 63 insertions(+), 59 deletions(-)

diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 731cc104c56f..bb96ca0f774b 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -31,7 +31,7 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
-Rust (optional)        1.72.1           rustc --version
+Rust (optional)        1.73.0           rustc --version
 bindgen (optional)     0.65.1           bindgen --version
 GNU make               3.82             make --version
 bash                   4.2              bash --version
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index 51821feb20b1..8cb4a31cf6e5 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -6,11 +6,7 @@
 
 #[cfg(not(test))]
 use core::intrinsics;
-#[cfg(all(bootstrap, not(test)))]
-use core::intrinsics::{min_align_of_val, size_of_val};
 
-#[cfg(all(bootstrap, not(test)))]
-use core::ptr::Unique;
 #[cfg(not(test))]
 use core::ptr::{self, NonNull};
 
@@ -339,23 +335,6 @@ unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
     }
 }
 
-#[cfg(all(bootstrap, not(test)))]
-#[lang = "box_free"]
-#[inline]
-// This signature has to be the same as `Box`, otherwise an ICE will happen.
-// When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
-// well.
-// For example if `Box` is changed to  `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
-// this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
-unsafe fn box_free<T: ?Sized, A: Allocator>(ptr: Unique<T>, alloc: A) {
-    unsafe {
-        let size = size_of_val(ptr.as_ref());
-        let align = min_align_of_val(ptr.as_ref());
-        let layout = Layout::from_size_align_unchecked(size, align);
-        alloc.deallocate(From::from(ptr.cast()), layout)
-    }
-}
-
 // # Allocation error handler
 
 #[cfg(not(no_global_oom_handling))]
@@ -415,7 +394,6 @@ pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
             static __rust_alloc_error_handler_should_panic: u8;
         }
 
-        #[allow(unused_unsafe)]
         if unsafe { __rust_alloc_error_handler_should_panic != 0 } {
             panic!("memory allocation of {size} bytes failed")
         } else {
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
index bdab710f7737..9620eba17268 100644
--- a/rust/alloc/boxed.rs
+++ b/rust/alloc/boxed.rs
@@ -159,12 +159,12 @@
 use core::iter::FusedIterator;
 use core::marker::Tuple;
 use core::marker::Unsize;
-use core::mem;
+use core::mem::{self, SizedTypeProperties};
 use core::ops::{
     CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
 };
 use core::pin::Pin;
-use core::ptr::{self, Unique};
+use core::ptr::{self, NonNull, Unique};
 use core::task::{Context, Poll};
 
 #[cfg(not(no_global_oom_handling))]
@@ -483,8 +483,12 @@ pub fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocE
     where
         A: Allocator,
     {
-        let layout = Layout::new::<mem::MaybeUninit<T>>();
-        let ptr = alloc.allocate(layout)?.cast();
+        let ptr = if T::IS_ZST {
+            NonNull::dangling()
+        } else {
+            let layout = Layout::new::<mem::MaybeUninit<T>>();
+            alloc.allocate(layout)?.cast()
+        };
         unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
     }
 
@@ -553,8 +557,12 @@ pub fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocE
     where
         A: Allocator,
     {
-        let layout = Layout::new::<mem::MaybeUninit<T>>();
-        let ptr = alloc.allocate_zeroed(layout)?.cast();
+        let ptr = if T::IS_ZST {
+            NonNull::dangling()
+        } else {
+            let layout = Layout::new::<mem::MaybeUninit<T>>();
+            alloc.allocate_zeroed(layout)?.cast()
+        };
         unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
     }
 
@@ -679,14 +687,16 @@ pub fn new_zeroed_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
     #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn try_new_uninit_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
-        unsafe {
+        let ptr = if T::IS_ZST || len == 0 {
+            NonNull::dangling()
+        } else {
             let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
                 Ok(l) => l,
                 Err(_) => return Err(AllocError),
             };
-            let ptr = Global.allocate(layout)?;
-            Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
-        }
+            Global.allocate(layout)?.cast()
+        };
+        unsafe { Ok(RawVec::from_raw_parts_in(ptr.as_ptr(), len, Global).into_box(len)) }
     }
 
     /// Constructs a new boxed slice with uninitialized contents, with the memory
@@ -711,14 +721,16 @@ pub fn try_new_uninit_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, Al
     #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn try_new_zeroed_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
-        unsafe {
+        let ptr = if T::IS_ZST || len == 0 {
+            NonNull::dangling()
+        } else {
             let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
                 Ok(l) => l,
                 Err(_) => return Err(AllocError),
             };
-            let ptr = Global.allocate_zeroed(layout)?;
-            Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
-        }
+            Global.allocate_zeroed(layout)?.cast()
+        };
+        unsafe { Ok(RawVec::from_raw_parts_in(ptr.as_ptr(), len, Global).into_box(len)) }
     }
 }
 
@@ -1223,7 +1235,9 @@ fn drop(&mut self) {
 
         unsafe {
             let layout = Layout::for_value_raw(ptr.as_ptr());
-            self.1.deallocate(From::from(ptr.cast()), layout)
+            if layout.size() != 0 {
+                self.1.deallocate(From::from(ptr.cast()), layout);
+            }
         }
     }
 }
@@ -2173,7 +2187,7 @@ pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn E
         let err: Box<dyn Error> = self;
         <dyn Error>::downcast(err).map_err(|s| unsafe {
             // Reapply the `Send` marker.
-            mem::transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s)
+            Box::from_raw(Box::into_raw(s) as *mut (dyn Error + Send))
         })
     }
 }
@@ -2187,7 +2201,7 @@ pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>
         let err: Box<dyn Error> = self;
         <dyn Error>::downcast(err).map_err(|s| unsafe {
             // Reapply the `Send + Sync` marker.
-            mem::transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s)
+            Box::from_raw(Box::into_raw(s) as *mut (dyn Error + Send + Sync))
         })
     }
 }
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
index 115fcb053e73..73b9ffd845d9 100644
--- a/rust/alloc/lib.rs
+++ b/rust/alloc/lib.rs
@@ -60,7 +60,7 @@
 
 // To run alloc tests without x.py without ending up with two copies of alloc, Miri needs to be
 // able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
-// rustc itself never sets the feature, so this line has no affect there.
+// rustc itself never sets the feature, so this line has no effect there.
 #![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
 //
 #![allow(unused_attributes)]
@@ -90,6 +90,8 @@
 #![warn(missing_docs)]
 #![allow(explicit_outlives_requirements)]
 #![warn(multiple_supertrait_upcastable)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
+#![cfg_attr(not(bootstrap), allow(rustdoc::redundant_explicit_links))]
 //
 // Library features:
 // tidy-alphabetical-start
@@ -139,7 +141,6 @@
 #![feature(maybe_uninit_uninit_array_transpose)]
 #![feature(pattern)]
 #![feature(pointer_byte_offsets)]
-#![feature(provide_any)]
 #![feature(ptr_internals)]
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
index 65d5ce15828e..a7425582a323 100644
--- a/rust/alloc/raw_vec.rs
+++ b/rust/alloc/raw_vec.rs
@@ -471,16 +471,26 @@ fn shrink(&mut self, cap: usize) -> Result<(), TryReserveError> {
         let (ptr, layout) = if let Some(mem) = self.current_memory() { mem } else { return Ok(()) };
         // See current_memory() why this assert is here
         let _: () = const { assert!(mem::size_of::<T>() % mem::align_of::<T>() == 0) };
-        let ptr = unsafe {
-            // `Layout::array` cannot overflow here because it would have
-            // overflowed earlier when capacity was larger.
-            let new_size = mem::size_of::<T>().unchecked_mul(cap);
-            let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
-            self.alloc
-                .shrink(ptr, layout, new_layout)
-                .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
-        };
-        self.set_ptr_and_cap(ptr, cap);
+
+        // If shrinking to 0, deallocate the buffer. We don't reach this point
+        // for the T::IS_ZST case since current_memory() will have returned
+        // None.
+        if cap == 0 {
+            unsafe { self.alloc.deallocate(ptr, layout) };
+            self.ptr = Unique::dangling();
+            self.cap = 0;
+        } else {
+            let ptr = unsafe {
+                // `Layout::array` cannot overflow here because it would have
+                // overflowed earlier when capacity was larger.
+                let new_size = mem::size_of::<T>().unchecked_mul(cap);
+                let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
+                self.alloc
+                    .shrink(ptr, layout, new_layout)
+                    .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
+            };
+            self.set_ptr_and_cap(ptr, cap);
+        }
         Ok(())
     }
 }
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index a4e9a5002a6d..209a88cfe598 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -216,7 +216,7 @@
 ///
 /// # Indexing
 ///
-/// The `Vec` type allows to access values by index, because it implements the
+/// The `Vec` type allows access to values by index, because it implements the
 /// [`Index`] trait. An example will be more explicit:
 ///
 /// ```
@@ -3263,7 +3263,7 @@ pub fn extract_if<F>(&mut self, filter: F) -> ExtractIf<'_, T, F, A>
 /// [`copy_from_slice`]: slice::copy_from_slice
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "extend_ref", since = "1.2.0")]
-impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
+impl<'a, T: Copy + 'a, A: Allocator> Extend<&'a T> for Vec<T, A> {
     fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
         self.spec_extend(iter.into_iter())
     }
diff --git a/rust/alloc/vec/spec_extend.rs b/rust/alloc/vec/spec_extend.rs
index a6a735201e59..ada919537446 100644
--- a/rust/alloc/vec/spec_extend.rs
+++ b/rust/alloc/vec/spec_extend.rs
@@ -77,7 +77,7 @@ fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserv
 }
 
 #[cfg(not(no_global_oom_handling))]
-impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
+impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
 where
     I: Iterator<Item = &'a T>,
     T: Clone,
@@ -87,7 +87,7 @@ impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
     }
 }
 
-impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
+impl<'a, T: 'a, I, A: Allocator> TrySpecExtend<&'a T, I> for Vec<T, A>
 where
     I: Iterator<Item = &'a T>,
     T: Clone,
@@ -98,7 +98,7 @@ impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
 }
 
 #[cfg(not(no_global_oom_handling))]
-impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
 where
     T: Copy,
 {
@@ -108,7 +108,7 @@ fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
     }
 }
 
-impl<'a, T: 'a, A: Allocator + 'a> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+impl<'a, T: 'a, A: Allocator> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
 where
     T: Copy,
 {
diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
index fb8ac3f211de..bba2922c6ef7 100644
--- a/rust/compiler_builtins.rs
+++ b/rust/compiler_builtins.rs
@@ -19,6 +19,7 @@
 //! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
 //! [`compiler-rt`]: https://compiler-rt.llvm.org/
 
+#![allow(internal_features)]
 #![feature(compiler_builtins)]
 #![compiler_builtins]
 #![no_builtins]
diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index dc819612ff6a..fd5ffdb81bab 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -31,7 +31,7 @@ llvm)
 	fi
 	;;
 rustc)
-	echo 1.72.1
+	echo 1.73.0
 	;;
 bindgen)
 	echo 0.65.1
-- 
2.42.0

Re: [PATCH 3/3] rust: upgrade to Rust 1.73.0

[Martin Rodriguez Reboredo]

On 10/5/23 18:05, Miguel Ojeda wrote:
> This is the next upgrade to the Rust toolchain, from 1.72.1 to 1.73.0
> (i.e. the latest) [1].
> 
> See the upgrade policy [2] and the comments on the first upgrade in
> commit 3ed03f4da06e ("rust: upgrade to Rust 1.68.2").
> 
> # Unstable features
> 
> No unstable features (that we use) were stabilized.
> 
> Therefore, the only unstable feature allowed to be used outside
> the `kernel` crate is still `new_uninit`, though other code to be
> upstreamed may increase the list.
> 
> Please see [3] for details.
> 
> # Required changes
> 
> For the upgrade, the following changes are required:
> 
>    - Allow `internal_features` for `feature(compiler_builtins)` since
>      now Rust warns about using internal compiler and standard library
>      features (similar to how it also warns about incomplete ones) [4].
> 
>    - A cleanup for a documentation link thanks to a new `rustdoc` lint.
>      See previous commits for details.
> 
>    - A need to make an intra-doc link to a macro explicit, due to a
>      change in behavior in `rustdoc`. See previous commits for details.
> 
> # `alloc` upgrade and reviewing
> 
> The vast majority of changes are due to our `alloc` fork being upgraded
> at once.
> 
> There are two kinds of changes to be aware of: the ones coming from
> upstream, which we should follow as closely as possible, and the updates
> needed in our added fallible APIs to keep them matching the newer
> infallible APIs coming from upstream.
> 
> Instead of taking a look at the diff of this patch, an alternative
> approach is reviewing a diff of the changes between upstream `alloc` and
> the kernel's. This allows to easily inspect the kernel additions only,
> especially to check if the fallible methods we already have still match
> the infallible ones in the new version coming from upstream.
> 
> Another approach is reviewing the changes introduced in the additions in
> the kernel fork between the two versions. This is useful to spot
> potentially unintended changes to our additions.
> 
> To apply these approaches, one may follow steps similar to the following
> to generate a pair of patches that show the differences between upstream
> Rust and the kernel (for the subset of `alloc` we use) before and after
> applying this patch:
> 
>      # Get the difference with respect to the old version.
>      git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>      git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>          cut -d/ -f3- |
>          grep -Fv README.md |
>          xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>      git -C linux diff --patch-with-stat --summary -R > old.patch
>      git -C linux restore rust/alloc
> 
>      # Apply this patch.
>      git -C linux am rust-upgrade.patch
> 
>      # Get the difference with respect to the new version.
>      git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>      git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>          cut -d/ -f3- |
>          grep -Fv README.md |
>          xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>      git -C linux diff --patch-with-stat --summary -R > new.patch
>      git -C linux restore rust/alloc
> 
> Now one may check the `new.patch` to take a look at the additions (first
> approach) or at the difference between those two patches (second
> approach). For the latter, a side-by-side tool is recommended.
> 
> Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1730-2023-10-05 [1]
> Link: https://rust-for-linux.com/rust-version-policy [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
> Link: https://github.com/rust-lang/compiler-team/issues/596 [4]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> [...]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

Re: [PATCH 3/3] rust: upgrade to Rust 1.73.0

[Alice Ryhl]

Miguel Ojeda <ojeda@kernel.org> writes:
> This is the next upgrade to the Rust toolchain, from 1.72.1 to 1.73.0
> (i.e. the latest) [1].
> 
> See the upgrade policy [2] and the comments on the first upgrade in
> commit 3ed03f4da06e ("rust: upgrade to Rust 1.68.2").
> 
> # Unstable features
> 
> No unstable features (that we use) were stabilized.
> 
> Therefore, the only unstable feature allowed to be used outside
> the `kernel` crate is still `new_uninit`, though other code to be
> upstreamed may increase the list.
> 
> Please see [3] for details.
> 
> # Required changes
> 
> For the upgrade, the following changes are required:
> 
>   - Allow `internal_features` for `feature(compiler_builtins)` since
>     now Rust warns about using internal compiler and standard library
>     features (similar to how it also warns about incomplete ones) [4].
> 
>   - A cleanup for a documentation link thanks to a new `rustdoc` lint.
>     See previous commits for details.
> 
>   - A need to make an intra-doc link to a macro explicit, due to a
>     change in behavior in `rustdoc`. See previous commits for details.
> 
> # `alloc` upgrade and reviewing
> 
> The vast majority of changes are due to our `alloc` fork being upgraded
> at once.
> 
> There are two kinds of changes to be aware of: the ones coming from
> upstream, which we should follow as closely as possible, and the updates
> needed in our added fallible APIs to keep them matching the newer
> infallible APIs coming from upstream.
> 
> Instead of taking a look at the diff of this patch, an alternative
> approach is reviewing a diff of the changes between upstream `alloc` and
> the kernel's. This allows to easily inspect the kernel additions only,
> especially to check if the fallible methods we already have still match
> the infallible ones in the new version coming from upstream.
> 
> Another approach is reviewing the changes introduced in the additions in
> the kernel fork between the two versions. This is useful to spot
> potentially unintended changes to our additions.
> 
> To apply these approaches, one may follow steps similar to the following
> to generate a pair of patches that show the differences between upstream
> Rust and the kernel (for the subset of `alloc` we use) before and after
> applying this patch:
> 
>     # Get the difference with respect to the old version.
>     git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>     git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>         cut -d/ -f3- |
>         grep -Fv README.md |
>         xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>     git -C linux diff --patch-with-stat --summary -R > old.patch
>     git -C linux restore rust/alloc
> 
>     # Apply this patch.
>     git -C linux am rust-upgrade.patch
> 
>     # Get the difference with respect to the new version.
>     git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>     git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>         cut -d/ -f3- |
>         grep -Fv README.md |
>         xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>     git -C linux diff --patch-with-stat --summary -R > new.patch
>     git -C linux restore rust/alloc
> 
> Now one may check the `new.patch` to take a look at the additions (first
> approach) or at the difference between those two patches (second
> approach). For the latter, a side-by-side tool is recommended.

I followed these instructions, and it looks good to me:

    $ diff old.patch new.patch 
    18c18
    < index e24a0fe51bda..51821feb20b1 100644
    ---
    > index 5205ed9fb50a..8cb4a31cf6e5 100644
    28c28
    < index 8ef2bac9282c..bdab710f7737 100644
    ---
    > index 96b93830f960..9620eba17268 100644
    60c60
    < index 967ad3a0e690..115fcb053e73 100644
    ---
    > index ffe6d6373875..73b9ffd845d9 100644
    69c69
    < @@ -107,7 +109,7 @@
    ---
    > @@ -109,7 +111,7 @@
    78c78
    < @@ -217,6 +219,7 @@
    ---
    > @@ -218,6 +220,7 @@
    86c86
    < @@ -237,15 +240,19 @@
    ---
    > @@ -238,15 +241,19 @@
    107c107
    < index dfd30d99cf04..65d5ce15828e 100644
    ---
    > index 01b03de6acb5..a7425582a323 100644
    238c238
    < index 598ecf05e824..a4e9a5002a6d 100644
    ---
    > index e45ddc7896be..209a88cfe598 100644
    679c679
    < index 56065ce565bf..a6a735201e59 100644
    ---
    > index e2f865d0f716..ada919537446 100644
    756c756
    <  impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
    ---
    >  impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
    759c759
    < @@ -46,6 +87,17 @@ impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
    ---
    > @@ -46,6 +87,17 @@ impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
    763c763
    < +impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
    ---
    > +impl<'a, T: 'a, I, A: Allocator> TrySpecExtend<&'a T, I> for Vec<T, A>
    774c774
    <  impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
    ---
    >  impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
    782c782
    < +impl<'a, T: 'a, A: Allocator + 'a> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
    ---
    > +impl<'a, T: 'a, A: Allocator> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>

> Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1730-2023-10-05 [1]
> Link: https://rust-for-linux.com/rust-version-policy [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
> Link: https://github.com/rust-lang/compiler-team/issues/596 [4]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH 3/3] rust: upgrade to Rust 1.73.0

[Vincenzo Palazzo]

> The vast majority of changes are due to our `alloc` fork being upgraded
> at once.

Ah this is annoying sometimes :/

>
> There are two kinds of changes to be aware of: the ones coming from
> upstream, which we should follow as closely as possible, and the updates
> needed in our added fallible APIs to keep them matching the newer
> infallible APIs coming from upstream.
>
> Instead of taking a look at the diff of this patch, an alternative
> approach is reviewing a diff of the changes between upstream `alloc` and
> the kernel's. This allows to easily inspect the kernel additions only,
> especially to check if the fallible methods we already have still match
> the infallible ones in the new version coming from upstream.
>
> Another approach is reviewing the changes introduced in the additions in
> the kernel fork between the two versions. This is useful to spot
> potentially unintended changes to our additions.
>
> To apply these approaches, one may follow steps similar to the following
> to generate a pair of patches that show the differences between upstream
> Rust and the kernel (for the subset of `alloc` we use) before and after
> applying this patch:
>
>     # Get the difference with respect to the old version.
>     git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>     git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>         cut -d/ -f3- |
>         grep -Fv README.md |
>         xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>     git -C linux diff --patch-with-stat --summary -R > old.patch
>     git -C linux restore rust/alloc
>
>     # Apply this patch.
>     git -C linux am rust-upgrade.patch
>
>     # Get the difference with respect to the new version.
>     git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
>     git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
>         cut -d/ -f3- |
>         grep -Fv README.md |
>         xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
>     git -C linux diff --patch-with-stat --summary -R > new.patch
>     git -C linux restore rust/alloc
>
> Now one may check the `new.patch` to take a look at the additions (first
> approach) or at the difference between those two patches (second
> approach). For the latter, a side-by-side tool is recommended.
>
> Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1730-2023-10-05 [1]
> Link: https://rust-for-linux.com/rust-version-policy [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
> Link: https://github.com/rust-lang/compiler-team/issues/596 [4]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>  Documentation/process/changes.rst |  2 +-
>  rust/alloc/alloc.rs               | 22 --------------
>  rust/alloc/boxed.rs               | 48 ++++++++++++++++++++-----------
>  rust/alloc/lib.rs                 |  5 ++--
>  rust/alloc/raw_vec.rs             | 30 ++++++++++++-------
>  rust/alloc/vec/mod.rs             |  4 +--
>  rust/alloc/vec/spec_extend.rs     |  8 +++---
>  rust/compiler_builtins.rs         |  1 +
>  scripts/min-tool-version.sh       |  2 +-
>  9 files changed, 63 insertions(+), 59 deletions(-)
>
> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> index 731cc104c56f..bb96ca0f774b 100644
> --- a/Documentation/process/changes.rst

Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

Re: [PATCH 0/3] Rust 1.73.0 upgrade

[Miguel Ojeda]

On Thu, Oct 5, 2023 at 11:06 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> This is the next upgrade to the Rust toolchain since the initial Rust
> merge, from 1.72.1 to 1.73.0 (i.e. the latest, released today).
>
> Please see the main patch message for a long explanation of the upgrade,
> the policy for future upgrades and some indications on how to easily
> review this.
>
> The series is based on `rust-next`.

Applied to `rust-next` -- thanks everyone!

Cheers,
Miguel