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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 11/29/24 10:41, Alice Ryhl wrote: > On Thu, Nov 28, 2024 at 3:13 PM Paolo Bonzini 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 >> --- >> 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( >> name: fmt::Arguments<'_>, >> tagset: Arc>, >> ) -> Result> { >> - // 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 { >> _p: PhantomData, >> } >> >> +// 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. Ok, I will look into using the bindgen doc comments then. It looks like the idea is not dead on arrival at least! Thanks for the review. Paolo