Download raw body.
Kill UVM_LK_ENTER/EXIT
Diff below removes the `lockflags' argument from uvm_map_pageable(),
grabs the exclusive lock explicitly where necessary and adds locking
assertions in uvm_map_pageable_wire() and uvm_map_pageable().
As a result uvm_map_pageable_wire() becomes much simpler, the locking
requirement becomes obvious and I don't have to think to understand
where locks are released.
I'd like to get this in before fixing uvm_vslock_device() which suffers
from the same race that was present in uvm_vslock().
ok?
Index: dev/ic/psp.c
===================================================================
RCS file: /cvs/src/sys/dev/ic/psp.c,v
diff -u -p -r1.16 psp.c
--- dev/ic/psp.c 25 Apr 2025 19:10:50 -0000 1.16
+++ dev/ic/psp.c 14 May 2025 13:19:36 -0000
@@ -504,7 +504,9 @@ psp_launch_update_data(struct psp_softc
end = start + size;
/* Wire mapping. */
- error = uvm_map_pageable(&p->p_vmspace->vm_map, start, end, FALSE, 0);
+ vm_map_lock(&p->p_vmspace->vm_map);
+ error = uvm_map_pageable(&p->p_vmspace->vm_map, start, end, FALSE);
+ vm_map_unlock(&p->p_vmspace->vm_map);
if (error)
goto out;
@@ -533,7 +535,9 @@ out:
* Unwire again. Ignore new error. Error has either been set,
* or PSP command has already succeeded.
*/
- (void) uvm_map_pageable(&p->p_vmspace->vm_map, start, end, TRUE, 0);
+ vm_map_lock(&p->p_vmspace->vm_map);
+ (void) uvm_map_pageable(&p->p_vmspace->vm_map, start, end, TRUE);
+ vm_map_unlock(&p->p_vmspace->vm_map);
return (error);
}
Index: uvm/uvm_extern.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_extern.h,v
diff -u -p -r1.180 uvm_extern.h
--- uvm/uvm_extern.h 19 Nov 2024 06:18:26 -0000 1.180
+++ uvm/uvm_extern.h 14 May 2025 13:19:36 -0000
@@ -153,12 +153,6 @@ typedef int vm_prot_t;
#define UVM_PLA_USERESERVE 0x0040 /* can allocate from kernel reserve */
/*
- * lockflags that control the locking behavior of various functions.
- */
-#define UVM_LK_ENTER 0x00000001 /* map locked on entry */
-#define UVM_LK_EXIT 0x00000002 /* leave map locked on exit */
-
-/*
* flags to uvm_page_physload.
*/
#define PHYSLOAD_DEVICE 0x01 /* don't add to the page queue */
@@ -388,7 +383,7 @@ int uvm_map(vm_map_t, vaddr_t *, vsize
struct uvm_object *, voff_t, vsize_t, unsigned int);
int uvm_mapanon(vm_map_t, vaddr_t *, vsize_t, vsize_t, unsigned int);
int uvm_map_pageable(vm_map_t, vaddr_t,
- vaddr_t, boolean_t, int);
+ vaddr_t, boolean_t);
int uvm_map_pageable_all(vm_map_t, int, vsize_t);
boolean_t uvm_map_checkprot(vm_map_t, vaddr_t,
vaddr_t, vm_prot_t);
Index: uvm/uvm_glue.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_glue.c,v
diff -u -p -r1.88 uvm_glue.c
--- uvm/uvm_glue.c 21 Mar 2025 13:19:33 -0000 1.88
+++ uvm/uvm_glue.c 14 May 2025 13:19:36 -0000
@@ -108,13 +108,17 @@ uvm_vslock(struct proc *p, caddr_t addr,
{
struct vm_map *map = &p->p_vmspace->vm_map;
vaddr_t start, end;
+ int error;
start = trunc_page((vaddr_t)addr);
end = round_page((vaddr_t)addr + len);
if (end <= start)
return (EINVAL);
- return uvm_map_pageable(map, start, end, FALSE, 0);
+ vm_map_lock(map);
+ error = uvm_map_pageable(map, start, end, FALSE);
+ vm_map_unlock(map);
+ return error;
}
/*
@@ -132,7 +136,9 @@ uvm_vsunlock(struct proc *p, caddr_t add
end = round_page((vaddr_t)addr + len);
KASSERT(end > start);
- uvm_map_pageable(map, start, end, TRUE, 0);
+ vm_map_lock(map);
+ uvm_map_pageable(map, start, end, TRUE);
+ vm_map_unlock(map);
}
/*
Index: uvm/uvm_map.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_map.c,v
diff -u -p -r1.341 uvm_map.c
--- uvm/uvm_map.c 21 Apr 2025 14:46:18 -0000 1.341
+++ uvm/uvm_map.c 14 May 2025 13:19:36 -0000
@@ -135,7 +135,7 @@ void uvm_map_pageable_pgon(struct vm_
vaddr_t, vaddr_t);
int uvm_map_pageable_wire(struct vm_map*,
struct vm_map_entry*, struct vm_map_entry*,
- vaddr_t, vaddr_t, int);
+ vaddr_t, vaddr_t);
void uvm_map_setup_entries(struct vm_map*);
void uvm_map_setup_md(struct vm_map*);
void uvm_map_teardown(struct vm_map*);
@@ -2057,14 +2057,10 @@ uvm_map_pageable_pgon(struct vm_map *map
/*
* Mark all entries from first until end (exclusive) as wired.
- *
- * Lockflags determines the lock state on return from this function.
- * Lock must be exclusive on entry.
*/
int
uvm_map_pageable_wire(struct vm_map *map, struct vm_map_entry *first,
- struct vm_map_entry *end, vaddr_t start_addr, vaddr_t end_addr,
- int lockflags)
+ struct vm_map_entry *end, vaddr_t start_addr, vaddr_t end_addr)
{
struct vm_map_entry *iter;
#ifdef DIAGNOSTIC
@@ -2072,6 +2068,8 @@ uvm_map_pageable_wire(struct vm_map *map
#endif
int error;
+ vm_map_assert_wrlock(map);
+
/*
* Wire pages in two passes:
*
@@ -2129,12 +2127,12 @@ uvm_map_pageable_wire(struct vm_map *map
vm_map_lock(map);
vm_map_unbusy(map);
- if (error) {
#ifdef DIAGNOSTIC
- if (timestamp_save != map->timestamp)
- panic("uvm_map_pageable_wire: stale map");
+ if (timestamp_save != map->timestamp)
+ panic("stale map");
#endif
+ if (error) {
/*
* first is no longer needed to restart loops.
* Use it as iterator to unmap successful mappings.
@@ -2162,37 +2160,20 @@ uvm_map_pageable_wire(struct vm_map *map
iter->wired_count--;
}
-
- if ((lockflags & UVM_LK_EXIT) == 0)
- vm_map_unlock(map);
- return error;
}
-
- if ((lockflags & UVM_LK_EXIT) == 0) {
- vm_map_unlock(map);
- } else {
-#ifdef DIAGNOSTIC
- if (timestamp_save != map->timestamp)
- panic("uvm_map_pageable_wire: stale map");
-#endif
- }
- return 0;
+ return error;
}
/*
* uvm_map_pageable: set pageability of a range in a map.
*
- * Flags:
- * UVM_LK_ENTER: map is already locked by caller
- * UVM_LK_EXIT: don't unlock map on exit
- *
* The full range must be in use (entries may not have fspace != 0).
* UVM_ET_HOLE counts as unmapped.
*/
int
uvm_map_pageable(struct vm_map *map, vaddr_t start, vaddr_t end,
- boolean_t new_pageable, int lockflags)
+ boolean_t new_pageable)
{
struct vm_map_entry *first, *last, *tmp;
int error;
@@ -2210,8 +2191,7 @@ uvm_map_pageable(struct vm_map *map, vad
return EINVAL; /* why? see second XXX below */
KASSERT(map->flags & VM_MAP_PAGEABLE);
- if ((lockflags & UVM_LK_ENTER) == 0)
- vm_map_lock(map);
+ vm_map_assert_wrlock(map);
/*
* Find first entry.
@@ -2282,8 +2262,6 @@ uvm_map_pageable(struct vm_map *map, vad
error = 0;
out:
- if ((lockflags & UVM_LK_EXIT) == 0)
- vm_map_unlock(map);
return error;
} else {
/*
@@ -2303,8 +2281,7 @@ out:
} else
tmp = last;
- return uvm_map_pageable_wire(map, first, tmp, start, end,
- lockflags);
+ return uvm_map_pageable_wire(map, first, tmp, start, end);
}
}
@@ -2370,7 +2347,7 @@ uvm_map_pageable_all(struct vm_map *map,
* uvm_map_pageable_wire will release lock
*/
return uvm_map_pageable_wire(map, RBT_MIN(uvm_map_addr, &map->addr),
- NULL, map->min_offset, map->max_offset, 0);
+ NULL, map->min_offset, map->max_offset);
}
/*
@@ -3196,7 +3175,7 @@ uvm_map_protect(struct vm_map *map, vadd
old_prot == PROT_NONE &&
new_prot != PROT_NONE) {
if (uvm_map_pageable(map, iter->start, iter->end,
- FALSE, UVM_LK_ENTER | UVM_LK_EXIT) != 0) {
+ FALSE) != 0) {
/*
* If locking the entry fails, remember the
* error if it's the first one. Note we
Index: uvm/uvm_mmap.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_mmap.c,v
diff -u -p -r1.198 uvm_mmap.c
--- uvm/uvm_mmap.c 6 Apr 2025 20:20:11 -0000 1.198
+++ uvm/uvm_mmap.c 14 May 2025 13:19:36 -0000
@@ -821,6 +821,7 @@ sys_mlock(struct proc *p, void *v, regis
syscallarg(const void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
+ vm_map_t map = &p->p_vmspace->vm_map;
vaddr_t addr;
vsize_t size, pageoff;
int error;
@@ -838,7 +839,7 @@ sys_mlock(struct proc *p, void *v, regis
return EAGAIN;
#ifdef pmap_wired_count
- if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
+ if (size + ptoa(pmap_wired_count(vm_map_pmap(map))) >
lim_cur(RLIMIT_MEMLOCK))
return EAGAIN;
#else
@@ -846,8 +847,9 @@ sys_mlock(struct proc *p, void *v, regis
return error;
#endif
- error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, FALSE,
- 0);
+ vm_map_lock(map);
+ error = uvm_map_pageable(map, addr, addr+size, FALSE);
+ vm_map_unlock(map);
return error == 0 ? 0 : ENOMEM;
}
@@ -862,6 +864,7 @@ sys_munlock(struct proc *p, void *v, reg
syscallarg(const void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
+ vm_map_t map = &p->p_vmspace->vm_map;
vaddr_t addr;
vsize_t size, pageoff;
int error;
@@ -880,8 +883,9 @@ sys_munlock(struct proc *p, void *v, reg
return error;
#endif
- error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, TRUE,
- 0);
+ vm_map_lock(map);
+ error = uvm_map_pageable(map, addr, addr+size, TRUE);
+ vm_map_unlock(map);
return error == 0 ? 0 : ENOMEM;
}
@@ -962,12 +966,9 @@ uvm_mmaplock(vm_map_t map, vaddr_t *addr
KERNEL_UNLOCK();
return error;
}
- /*
- * uvm_map_pageable() always returns the map
- * unlocked.
- */
- error = uvm_map_pageable(map, *addr, *addr + size,
- FALSE, UVM_LK_ENTER);
+
+ error = uvm_map_pageable(map, *addr, *addr + size, FALSE);
+ vm_map_unlock(map);
if (error != 0) {
/* unmap the region! */
uvm_unmap(map, *addr, *addr + size);
Kill UVM_LK_ENTER/EXIT