X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmmap.c;h=12334aecf8ad3d74b62f93da8db6f529e981d51d;hb=414edcd32aa54bad8827e7c74cace168006c5fab;hp=9da23c1ef9dce6ea1710d2f36d3e0c7ece033876;hpb=1363c3cd8603a913a27e2995dccbd70d5312d8e6;p=linux-2.6

diff --git a/mm/mmap.c b/mm/mmap.c
index 9da23c1ef9..12334aecf8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -61,7 +61,7 @@ pgprot_t protection_map[16] = {
 
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
-int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
+int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
 atomic_t vm_committed_space = ATOMIC_INIT(0);
 
 /*
@@ -143,7 +143,11 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
 	   leave 3% of the size of this process for other processes */
 	allowed -= current->mm->total_vm / 32;
 
-	if (atomic_read(&vm_committed_space) < allowed)
+	/*
+	 * cast `allowed' as a signed long because vm_committed_space
+	 * sometimes has a negative value
+	 */
+	if (atomic_read(&vm_committed_space) < (long)allowed)
 		return 0;
 
 	vm_unacct_memory(pages);
@@ -199,13 +203,6 @@ static void remove_vm_struct(struct vm_area_struct *vma)
 	kmem_cache_free(vm_area_cachep, vma);
 }
 
-/*
- *  sys_brk() for the most part doesn't need the global kernel
- *  lock, except when an application is doing something nasty
- *  like trying to un-brk an area that has already been mapped
- *  to a regular file.  in this case, the unmapping will need
- *  to invoke file system routines that need the global lock.
- */
 asmlinkage unsigned long sys_brk(unsigned long brk)
 {
 	unsigned long rlim, retval;
@@ -1267,6 +1264,9 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 			return (mm->free_area_cache = addr-len);
 	}
 
+	if (mm->mmap_base < len)
+		goto bottomup;
+
 	addr = mm->mmap_base-len;
 
 	do {
@@ -1288,6 +1288,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 		addr = vma->vm_start-len;
 	} while (len < vma->vm_start);
 
+bottomup:
 	/*
 	 * A failed mmap() very likely causes application failure,
 	 * so fall back to the bottom-up function here. This scenario