2007-11-27 Neal H. Walfield <neal@gnu.org>

	* as.c: Include <pthread.h>.  Remove dead code.
	(free_spaces_lock): New variable.
	(free_space_split): Assert that it is held.
	(as_alloc): Make thread-safe.
	(as_alloc_at): Likewise.
	(as_free): Likewise.
	(as_alloced_dump): Likewise.
	* storage.c: Include <pthread.h> and <atomic.h>.
	(free_count): Make a uatomic32_t, rather than an int.  Update
	users to access it using atomic operations.
	(struct storage_desc): New field, lock.
	(storage_descs_lock): New global variable.
	(link): Assert that STORAGE_DESCS_LOCK is held.
	(unlink): Likewise.  Don't assert that E->NEXT is NULL, which is
	valid.
	(slab_space_reserve): Make an atomicptr_t, rather than a void *.
	Update users to access it using atomic operations.
	(check_slab_space_reserve): Rewrite function to be thread-safe.
	(storage_desc_free): Assert that STORAGE_DESCS_LOCK is held.
	(storage_alloc): Rewrite function to be thread-safe.
	(storage_free): Likewise.
	(storage_init): Take STORAGE_DESCS_LOCK.  Initialize SDESC->LOCK.
	* capalloc.c: Include <pthread.h>.
	(struct cappage_desc): New field, lock.
	(unlink): Don't assert E->NEXT.
	(cappage_descs_lock): New variable.
	(capalloc): Make thread safe.
	(capfree): Likewise.
	* pager.h: Include <pthread.h>.
	(pager_fault_t): Note that PAGER->LOCK will be held.
	(struct pager): New field, lock.
	(pagers_lock): New declaration.
	(pager_install): Note locking requirements.
	(pager_relocate): Likewise.
	(pager_deinstall): Likewise.
	* pager.c (pagers_lock): New definition.
	(pager_install): Add asserts.
	(pager_relocate): Likewise.
	(pager_deinstall): Likewise.
	(pager_fault): Likewise.  Make function thread-safe.
	* anonymous.c (struct storage_desc): Add comment about locking.
	(fault): Add assert.
	(anonymous_pager_alloc): Take PAGERS_LOCK before calling
	pager_install and drop it afterwards.
	(anonymous_pager_destroy): Take PAGERS_LOCK before calling
	pager_deinstall and drop it afterwards.  Take ANON->PAGER.LOCK.

1 files changed, 13 insertions, 0 deletions

diff --git a/libhurd-mm/anonymous.c b/libhurd-mm/anonymous.c
index 07a5a15..d4f7b78 100644
--- a/libhurd-mm/anonymous.c
+++ b/libhurd-mm/anonymous.c
@@ -34,6 +34,7 @@
 
 #define DISCARDABLE(a) ((a)->flags & ANONYMOUS_DISCARDABLE)
 
+/* All fields are protected by the pager's lock.  */
 struct storage_desc
 {
   hurd_btree_node_t node;
@@ -131,6 +132,8 @@ static bool
 fault (struct pager *pager,
        addr_t addr, uintptr_t ip, struct exception_info info)
 {
+  assert (pthread_mutex_trylock (&pager->lock) == EBUSY);
+
   struct anonymous_pager *anon = (struct anonymous_pager *) pager;
 
   addr_t page;
@@ -209,7 +212,9 @@ anonymous_pager_alloc (addr_t activity,
   anon->pager.region.start = addr_chop (PTR_TO_ADDR (addr), PAGESIZE_LOG2);
   anon->pager.region.count = size >> PAGESIZE_LOG2;
 
+  pthread_mutex_lock (&pagers_lock);
   bool r = pager_install (&anon->pager);
+  pthread_mutex_unlock (&pagers_lock);
   if (! r)
     /* Ooops!  There is a region conflict.  */
     {
@@ -223,9 +228,15 @@ anonymous_pager_alloc (addr_t activity,
 void
 anonymous_pager_destroy (struct anonymous_pager *anon)
 {
+  pthread_mutex_lock (&pagers_lock);
+
   /* Deinstall the pager.  */
   pager_deinstall (&anon->pager);
 
+  pthread_mutex_unlock (&pagers_lock);
+
+  pthread_mutex_lock (&anon->pager.lock);
+
   /* Free the allocated storage.  */
   hurd_btree_storage_desc_t *storage_descs;
   storage_descs = (hurd_btree_storage_desc_t *) &anon->storage;
@@ -239,6 +250,8 @@ anonymous_pager_destroy (struct anonymous_pager *anon)
       storage_desc_free (node);
     }
 
+  /* There is no need to unlock &anon->pager.lock: we free it.  */
+
   /* And free its storage.  */
   hurd_slab_dealloc (&anonymous_pager_slab, anon);
 }