This adds a parameter called keep_map_locked to vm_map_lookup()
that allows the function to return with the map locked.
This is to prepare for fixing a bug with gsync where the map
is locked twice by mistake.
Co-Authored-By: Sergey Bugaev <buga...@gmail.com>
---
i386/intel/read_fault.c | 4 ++--
kern/gsync.c | 2 +-
vm/vm_fault.c | 4 ++--
vm/vm_map.c | 9 ++++++---
vm/vm_map.h | 2 +-
5 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/i386/intel/read_fault.c b/i386/intel/read_fault.c
index 0b79e3d8..356145e1 100644
--- a/i386/intel/read_fault.c
+++ b/i386/intel/read_fault.c
@@ -61,7 +61,7 @@ intel_read_fault(
* Find the backing store object and offset into it
* to begin search.
*/
- result = vm_map_lookup(&map, vaddr, VM_PROT_READ, &version,
+ result = vm_map_lookup(&map, vaddr, VM_PROT_READ, FALSE, &version,
&object, &offset, &prot, &wired);
if (result != KERN_SUCCESS)
return (result);
@@ -133,7 +133,7 @@ intel_read_fault(
vm_offset_t retry_offset;
vm_prot_t retry_prot;
- result = vm_map_lookup(&map, vaddr, VM_PROT_READ, &version,
+ result = vm_map_lookup(&map, vaddr, VM_PROT_READ, FALSE, &version,
&retry_object, &retry_offset, &retry_prot,
&wired);
if (result != KERN_SUCCESS) {
diff --git a/kern/gsync.c b/kern/gsync.c
index e73a6cf0..19190349 100644
--- a/kern/gsync.c
+++ b/kern/gsync.c
@@ -134,7 +134,7 @@ probe_address (vm_map_t map, vm_offset_t addr,
vm_prot_t rprot;
boolean_t wired_p;
- if (vm_map_lookup (&map, addr, prot, &ver,
+ if (vm_map_lookup (&map, addr, prot, FALSE, &ver,
&vap->obj, &vap->off, &rprot, &wired_p) != KERN_SUCCESS)
return (-1);
else if ((rprot & prot) != prot)
diff --git a/vm/vm_fault.c b/vm/vm_fault.c
index c6e28004..d99425a3 100644
--- a/vm/vm_fault.c
+++ b/vm/vm_fault.c
@@ -1213,7 +1213,7 @@ kern_return_t vm_fault(
* it to begin the search.
*/
- if ((kr = vm_map_lookup(&map, vaddr, fault_type, &version,
+ if ((kr = vm_map_lookup(&map, vaddr, fault_type, FALSE, &version,
&object, &offset,
&prot, &wired)) != KERN_SUCCESS) {
goto done;
@@ -1375,7 +1375,7 @@ kern_return_t vm_fault(
* take another fault.
*/
kr = vm_map_lookup(&map, vaddr,
- fault_type & ~VM_PROT_WRITE, &version,
+ fault_type & ~VM_PROT_WRITE, FALSE, &version,
&retry_object, &retry_offset, &retry_prot,
&wired);
diff --git a/vm/vm_map.c b/vm/vm_map.c
index f221c532..47abea1b 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -4614,8 +4614,9 @@ vm_map_t vm_map_fork(vm_map_t old_map)
* In order to later verify this lookup, a "version"
* is returned.
*
- * The map should not be locked; it will not be
- * locked on exit. In order to guarantee the
+ * The map should not be locked; it will be
+ * unlocked on exit unless keep_map_locked is set and
+ * the lookup succeeds. In order to guarantee the
* existence of the returned object, it is returned
* locked.
*
@@ -4628,6 +4629,7 @@ kern_return_t vm_map_lookup(
vm_map_t *var_map, /* IN/OUT */
vm_offset_t vaddr,
vm_prot_t fault_type,
+ boolean_t keep_map_locked,
vm_map_version_t *out_version, /* OUT */
vm_object_t *object, /* OUT */
@@ -4649,7 +4651,8 @@ kern_return_t vm_map_lookup(
#define RETURN(why) \
{ \
- vm_map_unlock_read(map); \
+ if (!(keep_map_locked && (why == KERN_SUCCESS))) \
+ vm_map_unlock_read(map); \
return(why); \
}
diff --git a/vm/vm_map.h b/vm/vm_map.h
index a4949e4e..7e25d9f4 100644
--- a/vm/vm_map.h
+++ b/vm/vm_map.h
@@ -412,7 +412,7 @@ extern kern_return_t vm_map_inherit(vm_map_t,
vm_offset_t, vm_offset_t,
vm_inherit_t);
/* Look up an address */
-extern kern_return_t vm_map_lookup(vm_map_t *, vm_offset_t, vm_prot_t,
+extern kern_return_t vm_map_lookup(vm_map_t *, vm_offset_t, vm_prot_t,
boolean_t,
vm_map_version_t *, vm_object_t *,
vm_offset_t *, vm_prot_t *, boolean_t *);
/* Find a map entry */
--
2.43.0
