fix signature of Step::steps_between implementations

A recent nightly changed the signature of Step::steps_between to match the signature of Iterator::size_hint. This patch changes our implementations to match the new signature.
rust-osdev · Nov 30, 2024 · 0ee8fef · 0ee8fef
1 parent fb1e2db
commit 0ee8fef
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Showing 3 changed files with 31 additions and 18 deletions.
diff --git a/src/addr.rs b/src/addr.rs
@@ -226,15 +226,20 @@ impl VirtAddr {
     }
 
     // FIXME: Move this into the `Step` impl, once `Step` is stabilized.
-    pub(crate) fn steps_between_impl(start: &Self, end: &Self) -> Option<usize> {
-        let mut steps = end.0.checked_sub(start.0)?;
+    pub(crate) fn steps_between_impl(start: &Self, end: &Self) -> (usize, Option<usize>) {
+        let mut steps = if let Some(steps) = end.0.checked_sub(start.0) {
+            steps
+        } else {
+            return (0, None);
+        };
 
         // Check if we jumped the gap.
         if end.0.get_bit(47) && !start.0.get_bit(47) {
             steps = steps.checked_sub(0xffff_0000_0000_0000).unwrap();
         }
 
-        usize::try_from(steps).ok()
+        let steps = usize::try_from(steps).ok();
+        (steps.unwrap_or(usize::MAX), steps)
     }
 
     // FIXME: Move this into the `Step` impl, once `Step` is stabilized.
@@ -379,7 +384,7 @@ impl Sub<VirtAddr> for VirtAddr {
 
 #[cfg(feature = "step_trait")]
 impl Step for VirtAddr {
-    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
+    fn steps_between(start: &Self, end: &Self) -> (usize, Option<usize>) {
         Self::steps_between_impl(start, end)
     }
 
@@ -758,43 +763,49 @@ mod tests {
     #[test]
     #[cfg(feature = "step_trait")]
     fn virtaddr_steps_between() {
-        assert_eq!(Step::steps_between(&VirtAddr(0), &VirtAddr(0)), Some(0));
-        assert_eq!(Step::steps_between(&VirtAddr(0), &VirtAddr(1)), Some(1));
-        assert_eq!(Step::steps_between(&VirtAddr(1), &VirtAddr(0)), None);
+        assert_eq!(
+            Step::steps_between(&VirtAddr(0), &VirtAddr(0)),
+            (0, Some(0))
+        );
+        assert_eq!(
+            Step::steps_between(&VirtAddr(0), &VirtAddr(1)),
+            (1, Some(1))
+        );
+        assert_eq!(Step::steps_between(&VirtAddr(1), &VirtAddr(0)), (0, None));
         assert_eq!(
             Step::steps_between(
                 &VirtAddr(0x7fff_ffff_ffff),
                 &VirtAddr(0xffff_8000_0000_0000)
             ),
-            Some(1)
+            (1, Some(1))
         );
         assert_eq!(
             Step::steps_between(
                 &VirtAddr(0xffff_8000_0000_0000),
                 &VirtAddr(0x7fff_ffff_ffff)
             ),
-            None
+            (0, None)
         );
         assert_eq!(
             Step::steps_between(
                 &VirtAddr(0xffff_8000_0000_0000),
                 &VirtAddr(0xffff_8000_0000_0000)
             ),
-            Some(0)
+            (0, Some(0))
         );
         assert_eq!(
             Step::steps_between(
                 &VirtAddr(0xffff_8000_0000_0000),
                 &VirtAddr(0xffff_8000_0000_0001)
             ),
-            Some(1)
+            (1, Some(1))
         );
         assert_eq!(
             Step::steps_between(
                 &VirtAddr(0xffff_8000_0000_0001),
                 &VirtAddr(0xffff_8000_0000_0000)
             ),
-            None
+            (0, None)
         );
     }
 

diff --git a/src/instructions/tlb.rs b/src/instructions/tlb.rs
@@ -298,14 +298,14 @@ where
         if let Some(mut pages) = self.page_range {
             while !pages.is_empty() {
                 // Calculate out how many pages we still need to flush.
-                let count = Page::<S>::steps_between_impl(&pages.start, &pages.end).unwrap();
+                let count = Page::<S>::steps_between_impl(&pages.start, &pages.end).0;
 
                 // Make sure that we never jump the gap in the address space when flushing.
                 let second_half_start =
                     Page::<S>::containing_address(VirtAddr::new(0xffff_8000_0000_0000));
                 let count = if pages.start < second_half_start {
                     let count_to_second_half =
-                        Page::steps_between_impl(&pages.start, &second_half_start).unwrap();
+                        Page::steps_between_impl(&pages.start, &second_half_start).0;
                     cmp::min(count, count_to_second_half)
                 } else {
                     count

diff --git a/src/structures/paging/page.rs b/src/structures/paging/page.rs
@@ -150,9 +150,11 @@ impl<S: PageSize> Page<S> {
     }
 
     // FIXME: Move this into the `Step` impl, once `Step` is stabilized.
-    pub(crate) fn steps_between_impl(start: &Self, end: &Self) -> Option<usize> {
-        VirtAddr::steps_between_impl(&start.start_address, &end.start_address)
-            .map(|steps| steps / S::SIZE as usize)
+    pub(crate) fn steps_between_impl(start: &Self, end: &Self) -> (usize, Option<usize>) {
+        let (lower, upper) = VirtAddr::steps_between_impl(&start.start_address, &end.start_address);
+        let lower = lower / S::SIZE as usize;
+        let upper = upper.map(|steps| steps / S::SIZE as usize);
+        (lower, upper)
     }
 
     // FIXME: Move this into the `Step` impl, once `Step` is stabilized.
@@ -279,7 +281,7 @@ impl<S: PageSize> Sub<Self> for Page<S> {
 
 #[cfg(feature = "step_trait")]
 impl<S: PageSize> Step for Page<S> {
-    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
+    fn steps_between(start: &Self, end: &Self) -> (usize, Option<usize>) {
         Self::steps_between_impl(start, end)
     }