4 files changed, 81 insertions, 58 deletions

diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index fc97dd873974..0fe640f3aec6 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -7,14 +7,26 @@
 
 use crate::{
     bindings,
-    block::mq::{Operations, TagSet},
-    error::{self, from_err_ptr, Result},
-    fmt::{self, Write},
+    block::mq::{
+        Operations,
+        TagSet, //
+    },
+    error::{
+        from_err_ptr,
+        to_result, //
+    },
+    fmt::{
+        self,
+        Write, //
+    },
     prelude::*,
     static_lock_class,
     str::NullTerminatedFormatter,
     sync::Arc,
-    types::{ForeignOwnable, ScopeGuard},
+    types::{
+        ForeignOwnable,
+        ScopeGuard, //
+    }, //
 };
 
 /// A builder for [`GenDisk`].
@@ -54,7 +66,7 @@ impl GenDiskBuilder {
     /// and that it is a power of two.
     pub fn validate_block_size(size: u32) -> Result {
         if !(512..=bindings::PAGE_SIZE as u32).contains(&size) || !size.is_power_of_two() {
-            Err(error::code::EINVAL)
+            Err(EINVAL)
         } else {
             Ok(())
         }
@@ -63,7 +75,7 @@ impl GenDiskBuilder {
     /// Set the logical block size of the device to be built.
     ///
     /// This method will check that block size is a power of two and between 512
-    /// and 4096. If not, an error is returned and the block size is not set.
+    /// and `PAGE_SIZE`. If not, an error is returned and the block size is not set.
     ///
     /// This is the smallest unit the storage device can address. It is
     /// typically 4096 bytes.
@@ -76,7 +88,7 @@ impl GenDiskBuilder {
     /// Set the physical block size of the device to be built.
     ///
     /// This method will check that block size is a power of two and between 512
-    /// and 4096. If not, an error is returned and the block size is not set.
+    /// and `PAGE_SIZE`. If not, an error is returned and the block size is not set.
     ///
     /// This is the smallest unit a physical storage device can write
     /// atomically. It is usually the same as the logical block size but may be
@@ -125,30 +137,9 @@ impl GenDiskBuilder {
             )
         })?;
 
-        const TABLE: bindings::block_device_operations = bindings::block_device_operations {
-            submit_bio: None,
-            open: None,
-            release: None,
-            ioctl: None,
-            compat_ioctl: None,
-            check_events: None,
-            unlock_native_capacity: None,
-            getgeo: None,
-            set_read_only: None,
-            swap_slot_free_notify: None,
-            report_zones: None,
-            devnode: None,
-            alternative_gpt_sector: None,
-            get_unique_id: None,
-            // TODO: Set to `THIS_MODULE`.
-            owner: core::ptr::null_mut(),
-            pr_ops: core::ptr::null_mut(),
-            free_disk: None,
-            poll_bio: None,
-        };
-
-        // SAFETY: `gendisk` is a valid pointer as we initialized it above
-        unsafe { (*gendisk).fops = &TABLE };
+        // SAFETY: `gendisk` is a valid pointer. We have exclusive access,
+        // since the disk is not added to the VFS yet.
+        unsafe { (*gendisk).fops = &GenDisk::<T>::VTABLE };
 
         let cleanup_failure = ScopeGuard::new_with_data((gendisk, data), |(gendisk, data)| {
             // SAFETY: `gendisk` came from `__blk_mq_alloc_disk()` above and
@@ -177,7 +168,7 @@ impl GenDiskBuilder {
         // operation, so we will not race.
         unsafe { bindings::set_capacity(gendisk, self.capacity_sectors) };
 
-        crate::error::to_result(
+        to_result(
             // SAFETY: `gendisk` points to a valid and initialized instance of
             // `struct gendisk`.
             unsafe {
@@ -211,9 +202,22 @@ pub struct GenDisk<T: Operations> {
     gendisk: *mut bindings::gendisk,
 }
 
+impl<T: Operations> GenDisk<T> {
+    const VTABLE: bindings::block_device_operations = bindings::block_device_operations {
+        owner: crate::module::this_module::<T::OwnerModule>().as_ptr(),
+        ..pin_init::zeroed()
+    };
+}
+
 // SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a
-// `TagSet` It is safe to send this to other threads as long as T is Send.
-unsafe impl<T: Operations + Send> Send for GenDisk<T> {}
+// `TagSet`. It is safe to send this to other threads as long as these two are `Send`.
+unsafe impl<T> Send for GenDisk<T>
+where
+    T: Operations,
+    T::QueueData: Send,
+    Arc<TagSet<T>>: Send,
+{
+}
 
 impl<T: Operations> Drop for GenDisk<T> {
     fn drop(&mut self) {
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 861903e18fbf..08111d8368eb 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -6,11 +6,17 @@
 
 use crate::{
     bindings,
-    block::mq::{request::RequestDataWrapper, Request},
-    error::{from_result, Result},
+    block::mq::{
+        request::RequestDataWrapper,
+        Request, //
+    },
+    error::from_result,
     prelude::*,
-    sync::{aref::ARef, Refcount},
-    types::ForeignOwnable,
+    sync::{
+        aref::ARef,
+        Refcount, //
+    },
+    types::ForeignOwnable, //
 };
 use core::marker::PhantomData;
 
@@ -30,7 +36,7 @@ type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
 pub trait Operations: Sized {
     /// Data associated with the `struct request_queue` that is allocated for
     /// the `GenDisk` associated with this `Operations` implementation.
-    type QueueData: ForeignOwnable;
+    type QueueData: ForeignOwnable + Sync;
 
     /// Called by the kernel to queue a request with the driver. If `is_last` is
     /// `false`, the driver is allowed to defer committing the request.
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index ce3e30c81cb5..6115f9aec228 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -7,15 +7,21 @@
 use crate::{
     bindings,
     block::mq::Operations,
-    error::Result,
+    prelude::*,
     sync::{
-        aref::{ARef, AlwaysRefCounted},
+        aref::{
+            ARef,
+            AlwaysRefCounted, //
+        },
         atomic::Relaxed,
-        Refcount,
+        Refcount, //
     },
-    types::Opaque,
+    types::Opaque, //
+};
+use core::{
+    marker::PhantomData,
+    ptr::NonNull, //
 };
-use core::{marker::PhantomData, ptr::NonNull};
 
 /// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
 ///
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index dae9df408a86..5f04008820b7 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -4,17 +4,21 @@
 //!
 //! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h)
 
-use core::pin::Pin;
-
 use crate::{
     bindings,
-    block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
-    error::{self, Result},
-    prelude::try_pin_init,
-    types::Opaque,
+    block::mq::{
+        operations::OperationsVTable,
+        request::RequestDataWrapper,
+        Operations, //
+    },
+    error::to_result,
+    prelude::*,
+    types::Opaque, //
+};
+use core::{
+    convert::TryInto,
+    marker::PhantomData, //
 };
-use core::{convert::TryInto, marker::PhantomData};
-use pin_init::{pin_data, pinned_drop, PinInit};
 
 /// A wrapper for the C `struct blk_mq_tag_set`.
 ///
@@ -33,11 +37,7 @@ pub struct TagSet<T: Operations> {
 
 impl<T: Operations> TagSet<T> {
     /// Try to create a new tag set
-    pub fn new(
-        nr_hw_queues: u32,
-        num_tags: u32,
-        num_maps: u32,
-    ) -> impl PinInit<Self, error::Error> {
+    pub fn new(nr_hw_queues: u32, num_tags: u32, num_maps: u32) -> impl PinInit<Self, Error> {
         let tag_set: bindings::blk_mq_tag_set = pin_init::zeroed();
         let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper>()
             .try_into()
@@ -63,7 +63,7 @@ impl<T: Operations> TagSet<T> {
                 // SAFETY: we do not move out of `tag_set`.
                 let tag_set: &mut Opaque<_> = unsafe { Pin::get_unchecked_mut(tag_set) };
                 // SAFETY: `tag_set` is a reference to an initialized `blk_mq_tag_set`.
-                error::to_result( unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())})
+                to_result( unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())})
             }),
             _p: PhantomData,
         })
@@ -83,3 +83,10 @@ impl<T: Operations> PinnedDrop for TagSet<T> {
         unsafe { bindings::blk_mq_free_tag_set(self.inner.get()) };
     }
 }
+
+// SAFETY: It is safe to transfer ownership of `TagSet` between threads.
+unsafe impl<T: Operations> Send for TagSet<T> {}
+
+// SAFETY: It is safe to share `&TagSet` across threads. `TagSet` exposes no
+// `&self` methods that mutate the contained `blk_mq_tag_set`.
+unsafe impl<T: Operations> Sync for TagSet<T> {}