Remove as_user_inner.

src/context/memory.rs

@@ -16,7 +16,7 @@ use crate::arch::paging::PAGE_SIZE;
 use crate::memory::{Enomem, Frame, get_page_info, PageInfo, deallocate_frames, RefKind, AddRefError, RefCount, the_zeroed_frame};
 use crate::paging::mapper::{Flusher, InactiveFlusher, PageFlushAll};
 use crate::paging::{Page, PageFlags, PageMapper, RmmA, TableKind, VirtualAddress};
-use crate::scheme;
+use crate::scheme::{self, KernelSchemes};
 
 use super::context::HardBlockedReason;
 use super::file::FileDescription;
@@ -1728,7 +1728,13 @@ fn correct_inner<'l>(addr_space_lock: &'l Arc<RwLock<AddrSpace>>, mut addr_space
                 ref desc => (desc.scheme, desc.number),
             };
             let user_inner = scheme::schemes()
-                .get(scheme_id).and_then(|s| s.as_user_inner().transpose().ok().flatten())
+                .get(scheme_id).and_then(|s| {
+                    if let KernelSchemes::User(user) = s {
+                        user.inner.upgrade()
+                    } else {
+                        None
+                    }
+                })
                 .ok_or(PfError::Segv)?;
 
             let offset = file_ref.base_offset as u64 + (pages_from_grant_start * PAGE_SIZE) as u64;

src/scheme/mod.rs

@@ -38,7 +38,7 @@ use self::root::RootScheme;
 use self::serio::SerioScheme;
 use self::sys::SysScheme;
 use self::time::TimeScheme;
-use self::user::{UserInner, UserScheme};
+use self::user::UserScheme;
 
 /// When compiled with the "acpi" feature - `acpi:` - allows drivers to read a limited set of ACPI tables.
 #[cfg(all(feature = "acpi", any(target_arch = "x86", target_arch = "x86_64")))]
@@ -394,9 +394,6 @@ pub trait KernelScheme: Send + Sync + 'static {
     fn close(&self, id: usize) -> Result<()> {
         Err(Error::new(EBADF))
     }
-
-    // TODO: This demonstrates why we need to transition away from a dyn trait.
-    fn as_user_inner(&self) -> Option<Result<Arc<UserInner>>> { None }
 }
 
 #[derive(Debug)]

src/scheme/user.rs

@@ -752,7 +752,7 @@ fn page_range_containing(base: usize, size: usize) -> (Page, usize, usize) {
 /// `UserInner` has to be wrapped
 #[derive(Clone)]
 pub struct UserScheme {
-    inner: Weak<UserInner>
+    pub(crate) inner: Weak<UserInner>
 }
 
 impl UserScheme {
@@ -986,10 +986,6 @@ impl KernelScheme for UserScheme {
             Response::Fd(_) => Err(Error::new(EIO)),
         }
     }
-
-    fn as_user_inner(&self) -> Option<Result<Arc<UserInner>>> {
-        Some(self.inner.upgrade().ok_or(Error::new(ENODEV)))
-    }
 }
 
 #[derive(PartialEq)]