libpager: provide 'pager_create_alloc'

Add a variant to 'pager_create' that allocates memory for the user
hook next to the pager data increasing locality.

* console/pager.c (pager_clear_user_data): Fix type of 'idx', do not
free 'upi'.
(user_pager_create): Use the new function.
* doc/hurd.texi: Document new function.
* ext2fs/pager.c (pager_clear_user_data): Don't free 'upi'.
(diskfs_get_filemap): Use the new function.
* fatfs/pager.c (pager_clear_user_data): Don't free 'upi'.
(diskfs_get_filemap): Use the new function.
* isofs/pager.c (pager_clear_user_data): Don't free 'upi'.
(diskfs_get_filemap): Use the new function.
* libpager/pager-create.c (_pager_create): New generic allocation
function.
(pager_create): Use the new generic function.
(pager_create_alloc): New function.
* libpager/pager.h (pager_create_alloc): New prototype.

2 files changed, 49 insertions, 9 deletions

diff --git a/libpager/pager-create.c b/libpager/pager-create.c
index b583f023..b3b7c8f0 100644
--- a/libpager/pager-create.c
+++ b/libpager/pager-create.c
@@ -17,21 +17,19 @@
 
 #include "priv.h"
 
-/* Create and return a new pager with user info UPI.  */
-struct pager *
-pager_create (struct user_pager_info *upi,
-	      struct port_bucket *bucket,
-	      boolean_t may_cache,
-	      memory_object_copy_strategy_t copy_strategy,
-	      boolean_t notify_on_evict)
+static struct pager *
+_pager_create (size_t size,
+	       struct port_bucket *bucket,
+	       boolean_t may_cache,
+	       memory_object_copy_strategy_t copy_strategy,
+	       boolean_t notify_on_evict)
 {
   struct pager *p;
 
-  errno = ports_create_port (_pager_class, bucket, sizeof (struct pager), &p);
+  errno = ports_create_port (_pager_class, bucket, sizeof *p + size, &p);
   if (errno)
     return 0;
 
-  p->upi = upi;
   p->pager_state = NOTINIT;
   pthread_mutex_init (&p->interlock, NULL);
   pthread_cond_init (&p->wakeup, NULL);
@@ -50,6 +48,40 @@ pager_create (struct user_pager_info *upi,
   return p;
 }
 
+/* Create and return a new pager with user info UPI.  */
+struct pager *
+pager_create (struct user_pager_info *upi,
+	      struct port_bucket *bucket,
+	      boolean_t may_cache,
+	      memory_object_copy_strategy_t copy_strategy,
+	      boolean_t notify_on_evict)
+{
+  struct pager *p;
+
+  p = _pager_create (0, bucket, may_cache, copy_strategy, notify_on_evict);
+  if (p)
+    p->upi = upi;
+
+  return p;
+}
+
+struct pager *
+pager_create_alloc (size_t u_pager_size,
+		    struct port_bucket *bucket,
+		    boolean_t may_cache,
+		    memory_object_copy_strategy_t copy_strategy,
+		    boolean_t notify_on_evict)
+{
+  struct pager *p;
+
+  p = _pager_create (u_pager_size, bucket, may_cache, copy_strategy,
+		     notify_on_evict);
+  if (p)
+    p->upi = (struct user_pager_info *) ((char *) p + sizeof *p);
+
+  return p;
+}
+
 
 /* This causes the function to be run at startup by compiler magic. */
 static void create_class (void) __attribute__ ((constructor));
diff --git a/libpager/pager.h b/libpager/pager.h
index df4db686..d2a8d397 100644
--- a/libpager/pager.h
+++ b/libpager/pager.h
@@ -69,6 +69,14 @@ pager_create (struct user_pager_info *u_pager,
 	      memory_object_copy_strategy_t copy_strategy,
 	      boolean_t notify_on_evict);
 
+/* Likewise, but also allocate space for the user hook.  */
+struct pager *
+pager_create_alloc (size_t u_pager_size,
+		    struct port_bucket *bucket,
+		    boolean_t may_cache,
+		    memory_object_copy_strategy_t copy_strategy,
+		    boolean_t notify_on_evict);
+
 /* Return the user_pager_info struct associated with a pager. */
 struct user_pager_info *
 pager_get_upi (struct pager *p);