Merge branch 'clone_grant_using_fmap' into 'master'

Clone grant using fmap

See merge request redox-os/kernel!190

src/context/file.rs

@@ -7,7 +7,7 @@ use crate::scheme::{self, SchemeNamespace, SchemeId};
 use crate::syscall::error::{Result, Error, EBADF};
 
 /// A file description
-#[derive(Debug)]
+#[derive(Clone, Copy, Debug)]
 pub struct FileDescription {
     /// The namespace the file was opened from (used for debugging)
     pub namespace: SchemeNamespace,

src/context/memory.rs

@@ -290,7 +290,15 @@ pub struct Grant {
     mapped: bool,
     owned: bool,
     //TODO: This is probably a very heavy way to keep track of fmap'd files, perhaps move to the context?
-    pub desc_opt: Option<FileDescriptor>,
+    pub desc_opt: Option<GrantFileRef>,
+}
+#[derive(Clone, Debug)]
+pub struct GrantFileRef {
+    pub desc: FileDescriptor,
+    pub offset: usize,
+    // TODO: Can the flags maybe be stored together with the page flags. Should some flags be kept,
+    // and others discarded when re-fmapping on clone?
+    pub flags: MapFlags,
 }
 
 impl Grant {
@@ -363,7 +371,7 @@ impl Grant {
         }
     }
 
-    pub fn map_inactive(src: VirtualAddress, dst: VirtualAddress, size: usize, flags: PageFlags<RmmA>, desc_opt: Option<FileDescriptor>, inactive_table: &mut InactivePageTable) -> Grant {
+    pub fn map_inactive(src: VirtualAddress, dst: VirtualAddress, size: usize, flags: PageFlags<RmmA>, desc_opt: Option<GrantFileRef>, inactive_table: &mut InactivePageTable) -> Grant {
         let active_table = unsafe { ActivePageTable::new(src.kind()) };
         let mut inactive_mapper = inactive_table.mapper();
 
@@ -507,10 +515,9 @@ impl Grant {
 
         flush_all.flush();
 
-        if let Some(desc) = self.desc_opt.take() {
-            println!("Grant::unmap: close desc {:?}", desc);
+        if let Some(file_ref) = self.desc_opt.take() {
             //TODO: This imposes a large cost on unmapping, but that cost cannot be avoided without modifying fmap and funmap
-            let _ = desc.close();
+            let _ = file_ref.desc.close();
         }
 
         self.mapped = false;
@@ -533,10 +540,9 @@ impl Grant {
 
         ipi(IpiKind::Tlb, IpiTarget::Other);
 
-        if let Some(desc) = self.desc_opt.take() {
-            println!("Grant::unmap_inactive: close desc {:?}", desc);
+        if let Some(file_ref) = self.desc_opt.take() {
             //TODO: This imposes a large cost on unmapping, but that cost cannot be avoided without modifying fmap and funmap
-            let _ = desc.close();
+            let _ = file_ref.desc.close();
         }
 
         self.mapped = false;