[XFS] Add a greedy allocation interface, allocating within a min/max size

range.

SGI-PV: 955302
SGI-Modid: xfs-linux-melb:xfs-kern:26803a

Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/fs/xfs/linux-2.6/kmem.c b/fs/xfs/linux-2.6/kmem.c
index f77fe5c8fcc1..80b9340488e5 100644
--- a/fs/xfs/linux-2.6/kmem.c
+++ b/fs/xfs/linux-2.6/kmem.c
@@ -68,6 +68,22 @@ kmem_zalloc(size_t size, unsigned int __nocast flags)
         return ptr;
 }
 
+void *
+kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize,
+                   unsigned int __nocast flags)
+{
+        void    *ptr;
+
+        while (!(ptr = kmem_zalloc(maxsize, flags))) {
+                if ((maxsize >>= 1) <= minsize) {
+                        maxsize = minsize;
+                        flags = KM_SLEEP;
+                }
+        }
+        *size = maxsize;
+        return ptr;
+}
+
 void
 kmem_free(void *ptr, size_t size)
 {
diff --git a/fs/xfs/linux-2.6/kmem.h b/fs/xfs/linux-2.6/kmem.h
index 6d24274fb3cb..9ebabdf7829c 100644
--- a/fs/xfs/linux-2.6/kmem.h
+++ b/fs/xfs/linux-2.6/kmem.h
@@ -55,8 +55,9 @@ kmem_flags_convert(unsigned int __nocast flags)
 }
 
 extern void *kmem_alloc(size_t, unsigned int __nocast);
-extern void *kmem_realloc(void *, size_t, size_t, unsigned int __nocast);
 extern void *kmem_zalloc(size_t, unsigned int __nocast);
+extern void *kmem_zalloc_greedy(size_t *, size_t, size_t, unsigned int __nocast);
+extern void *kmem_realloc(void *, size_t, size_t, unsigned int __nocast);
 extern void  kmem_free(void *, size_t);
 
 /*