On Thu, Nov 28, 2024 at 3:13 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
Isolate the unsafety in the declaration of the Zeroable trait, instead of having
to use "unsafe" just to declare a struct. This is more similar to how you would
use "..Default::default()" (which is also a possibility here, but arguably
less efficient).
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
rust/kernel/block/mq/gen_disk.rs | 8 +++++---
rust/kernel/block/mq/tag_set.rs | 10 ++++++----
2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 708125dce96a..65342d065296 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -6,7 +6,7 @@
//! C header: [`include/linux/blk_mq.h`](srctree/include/linux/blk_mq.h)
use crate::block::mq::{raw_writer::RawWriter, Operations, TagSet};
-use crate::{bindings, error::from_err_ptr, error::Result, sync::Arc};
+use crate::{bindings, error::from_err_ptr, error::Result, init::Zeroable, sync::Arc};
use crate::{error, static_lock_class};
use core::fmt::{self, Write};
@@ -31,6 +31,9 @@ fn default() -> Self {
}
}
+// SAFETY: `bindings::queue_limits` contains only fields that are valid when zeroed.
+unsafe impl Zeroable for bindings::queue_limits {}
+
impl GenDiskBuilder {
/// Create a new instance.
pub fn new() -> Self {
@@ -93,8 +96,7 @@ pub fn build<T: Operations>(
name: fmt::Arguments<'_>,
tagset: Arc<TagSet<T>>,
) -> Result<GenDisk<T>> {
- // SAFETY: `bindings::queue_limits` contain only fields that are valid when zeroed.
- let mut lim: bindings::queue_limits = unsafe { core::mem::zeroed() };
+ let mut lim: bindings::queue_limits = Zeroable::ZERO;
lim.logical_block_size = self.logical_block_size;
lim.physical_block_size = self.physical_block_size;
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index f9a1ca655a35..1ff7366ca549 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -10,6 +10,7 @@
bindings,
block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
error,
+ init::Zeroable,
prelude::PinInit,
try_pin_init,
types::Opaque,
@@ -32,6 +33,10 @@ pub struct TagSet<T: Operations> {
_p: PhantomData<T>,
}
+// SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
+// all are allowed to be 0.
+unsafe impl Zeroable for bindings::blk_mq_tag_set {}
This will have to be reverted if we want to split up the kernel crate
due to the orphan rule.