Initialize field owner in file_operations

Initialized the field `owner` in struct `file_operations`. It's used
to increment the module ref count when a file is opened, to prevent the
module from being unloaded.

Fixes the issue #214

Signed-off-by: Roni Nevalainen <[email protected]>

Author: Roni Nevalainen

rust/kernel/chrdev.rs

@@ -116,7 +116,7 @@ impl<const N: usize> Registration<{ N }> {
                 cdev,
                 // SAFETY: The adapter doesn't retrieve any state yet, so it's compatible with any
                 // registration.
-                file_operations::FileOperationsVtable::<Self, T>::build(),
+                &file_operations::FileOperationsVtable::<Self, T>::build(&mut bindings::__this_module),
             );
             (*cdev).owner = this.this_module.0;
             let rc = bindings::cdev_add(cdev, inner.dev + inner.used as bindings::dev_t, 1);

rust/kernel/file_operations.rs

@@ -268,81 +268,80 @@ unsafe extern "C" fn poll_callback<T: FileOperations>(
 pub(crate) struct FileOperationsVtable<A, T>(marker::PhantomData<A>, marker::PhantomData<T>);
 
 impl<A: FileOpenAdapter, T: FileOpener<A::Arg>> FileOperationsVtable<A, T> {
-    const VTABLE: bindings::file_operations = bindings::file_operations {
-        open: Some(open_callback::<A, T>),
-        release: Some(release_callback::<T>),
-        read: if T::TO_USE.read {
-            Some(read_callback::<T>)
-        } else {
-            None
-        },
-        write: if T::TO_USE.write {
-            Some(write_callback::<T>)
-        } else {
-            None
-        },
-        llseek: if T::TO_USE.seek {
-            Some(llseek_callback::<T>)
-        } else {
-            None
-        },
-
-        check_flags: None,
-        compat_ioctl: if T::TO_USE.compat_ioctl {
-            Some(compat_ioctl_callback::<T>)
-        } else {
-            None
-        },
-        copy_file_range: None,
-        fallocate: None,
-        fadvise: None,
-        fasync: None,
-        flock: None,
-        flush: None,
-        fsync: if T::TO_USE.fsync {
-            Some(fsync_callback::<T>)
-        } else {
-            None
-        },
-        get_unmapped_area: None,
-        iterate: None,
-        iterate_shared: None,
-        iopoll: None,
-        lock: None,
-        mmap: if T::TO_USE.mmap {
-            Some(mmap_callback::<T>)
-        } else {
-            None
-        },
-        mmap_supported_flags: 0,
-        owner: ptr::null_mut(),
-        poll: if T::TO_USE.poll {
-            Some(poll_callback::<T>)
-        } else {
-            None
-        },
-        read_iter: None,
-        remap_file_range: None,
-        sendpage: None,
-        setlease: None,
-        show_fdinfo: None,
-        splice_read: None,
-        splice_write: None,
-        unlocked_ioctl: if T::TO_USE.ioctl {
-            Some(unlocked_ioctl_callback::<T>)
-        } else {
-            None
-        },
-        write_iter: None,
-    };
-
     /// Builds an instance of [`struct file_operations`].
     ///
     /// # Safety
     ///
     /// The caller must ensure that the adapter is compatible with the way the device is registered.
-    pub(crate) const unsafe fn build() -> &'static bindings::file_operations {
-        &Self::VTABLE
+    /// The called must ensure that the `module` argument passed equals to the right `THIS_MODULE`.
+    pub(crate) unsafe fn build(module: *mut bindings::module) -> bindings::file_operations {
+        bindings::file_operations {
+            open: Some(open_callback::<A, T>),
+            release: Some(release_callback::<T>),
+            read: if T::TO_USE.read {
+                Some(read_callback::<T>)
+            } else {
+                None
+            },
+            write: if T::TO_USE.write {
+                Some(write_callback::<T>)
+            } else {
+                None
+            },
+            llseek: if T::TO_USE.seek {
+                Some(llseek_callback::<T>)
+            } else {
+                None
+            },
+    
+            check_flags: None,
+            compat_ioctl: if T::TO_USE.compat_ioctl {
+                Some(compat_ioctl_callback::<T>)
+            } else {
+                None
+            },
+            copy_file_range: None,
+            fallocate: None,
+            fadvise: None,
+            fasync: None,
+            flock: None,
+            flush: None,
+            fsync: if T::TO_USE.fsync {
+                Some(fsync_callback::<T>)
+            } else {
+                None
+            },
+            get_unmapped_area: None,
+            iterate: None,
+            iterate_shared: None,
+            iopoll: None,
+            lock: None,
+            mmap: if T::TO_USE.mmap {
+                Some(mmap_callback::<T>)
+            } else {
+                None
+            },
+            mmap_supported_flags: 0,
+            owner: module,
+            poll: if T::TO_USE.poll {
+                Some(poll_callback::<T>)
+            } else {
+                None
+            },
+            read_iter: None,
+            remap_file_range: None,
+            sendpage: None,
+            setlease: None,
+            show_fdinfo: None,
+            splice_read: None,
+            splice_write: None,
+            unlocked_ioctl: if T::TO_USE.ioctl {
+                Some(unlocked_ioctl_callback::<T>)
+            } else {
+                None
+            },
+            write_iter: None,
+        }
     }
 }
 

rust/kernel/miscdev.rs

@@ -67,7 +67,7 @@ impl<T: Sync> Registration<T> {
         }
 
         // SAFETY: The adapter is compatible with `misc_register`.
-        this.mdev.fops = unsafe { FileOperationsVtable::<Self, F>::build() };
+        this.mdev.fops = unsafe { &FileOperationsVtable::<Self, F>::build(&mut bindings::__this_module) };
         this.mdev.name = name.as_ptr() as *const c_types::c_char;
         this.mdev.minor = minor.unwrap_or(bindings::MISC_DYNAMIC_MINOR as i32);