Author: ed
Date: Tue Aug  4 06:02:03 2015
New Revision: 286278
URL: https://svnweb.freebsd.org/changeset/base/286278

Log:
  Let the CloudABI futex code use umtx_keys.
  
  The CloudABI kernel still passes all of the cloudlibc unit tests.
  
  Reviewed by:  vangyzen
  Differential Revision:        https://reviews.freebsd.org/D3286

Modified:
  head/sys/compat/cloudabi/cloudabi_futex.c

Modified: head/sys/compat/cloudabi/cloudabi_futex.c
==============================================================================
--- head/sys/compat/cloudabi/cloudabi_futex.c   Tue Aug  4 06:01:13 2015        
(r286277)
+++ head/sys/compat/cloudabi/cloudabi_futex.c   Tue Aug  4 06:02:03 2015        
(r286278)
@@ -35,13 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/sx.h>
 #include <sys/systm.h>
-
-#include <vm/vm.h>
-#include <vm/vm_param.h>
-#include <vm/pmap.h>
-#include <vm/vm_extern.h>
-#include <vm/vm_map.h>
-#include <vm/vm_object.h>
+#include <sys/umtx.h>
 
 #include <compat/cloudabi/cloudabi_proto.h>
 #include <compat/cloudabi/cloudabi_syscalldefs.h>
@@ -105,13 +99,7 @@ struct futex_waiter;
 
 /* Identifier of a location in memory. */
 struct futex_address {
-       /* For process-private objects: address space of the process. */
-       struct vmspace *                fa_vmspace;
-       /* For process-shared objects: VM object containing the object. */
-       struct vm_object *              fa_vmobject;
-
-       /* Memory address within address space or offset within VM object. */
-       uintptr_t                       fa_offset;
+       struct umtx_key                 fa_key;
 };
 
 /* A set of waiting threads. */
@@ -225,61 +213,16 @@ static int
 futex_address_create(struct futex_address *fa, struct thread *td,
     const void *object, cloudabi_mflags_t scope)
 {
-       struct vmspace *vs;
-       struct vm_object *vo;
-       vm_map_t map;
-       vm_map_entry_t entry;
-       vm_pindex_t pindex;
-       vm_prot_t prot;
-       boolean_t wired;
 
-       /*
-        * Most of the time objects are stored in privately mapped
-        * anonymous memory. For these objects we wouldn't need to look
-        * up the corresponding VM object. The scope hint provided by
-        * userspace allows us to skip the VM map lookup for the common
-        * case.
-        *
-        * POSIX does permit enabling PTHREAD_PROCESS_SHARED on a lock
-        * stored in a private mapping, at the cost of additional
-        * performance overhead. Fall back to identifying the object by
-        * virtual memory address if the mapping isn't shared.
-        */
-       vs = td->td_proc->p_vmspace;
+       KASSERT(td == curthread,
+           ("Can only create umtx keys for the current thread"));
        switch (scope) {
-       case CLOUDABI_MAP_SHARED:
-               map = &vs->vm_map;
-               if (vm_map_lookup(&map, (vm_offset_t)object,
-                   VM_PROT_COPY | VM_PROT_WRITE, &entry, &vo, &pindex, &prot,
-                   &wired) != KERN_SUCCESS)
-                       return (EFAULT);
-
-               if (entry->inheritance == VM_INHERIT_SHARE) {
-                       /*
-                        * Address corresponds to a shared mapping.
-                        * Identify the address by its VM object.
-                        */
-                       fa->fa_vmspace = NULL;
-                       fa->fa_vmobject = vo;
-                       vm_object_reference(vo);
-                       fa->fa_offset = entry->offset - entry->start +
-                           (vm_offset_t)object;
-                       vm_map_lookup_done(map, entry);
-                       return (0);
-               }
-               vm_map_lookup_done(map, entry);
-               /* FALLTHROUGH */
        case CLOUDABI_MAP_PRIVATE:
-               /*
-                * Address corresponds to a private mapping. Never
-                * identify the address by its VM object, as shadow
-                * objects may get inserted if another thread forks.
-                * Simply use the VM space instead.
-                */
-               fa->fa_vmspace = vs;
-               fa->fa_vmobject = NULL;
-               fa->fa_offset = (uintptr_t)object;
-               return (0);
+               return (umtx_key_get(object, TYPE_FUTEX, THREAD_SHARE,
+                   &fa->fa_key));
+       case CLOUDABI_MAP_SHARED:
+               return (umtx_key_get(object, TYPE_FUTEX, AUTO_SHARE,
+                   &fa->fa_key));
        default:
                return (EINVAL);
        }
@@ -289,8 +232,7 @@ static void
 futex_address_free(struct futex_address *fa)
 {
 
-       if (fa->fa_vmobject != NULL)
-               vm_object_deallocate(fa->fa_vmobject);
+       umtx_key_release(&fa->fa_key);
 }
 
 static bool
@@ -298,10 +240,7 @@ futex_address_match(const struct futex_a
     const struct futex_address *fa2)
 {
 
-       /* Either fa_vmspace or fa_vmobject is NULL. */
-       return (fa1->fa_vmspace == fa2->fa_vmspace &&
-           fa1->fa_vmobject == fa2->fa_vmobject &&
-           fa1->fa_offset == fa2->fa_offset);
+       return (umtx_key_match(&fa1->fa_key, &fa2->fa_key));
 }
 
 /*
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