nommu: fix a number of issues with the per-MM VMA patch
Fix a number of issues with the per-MM VMA patch:
(1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on
a NOMMU system with more than 2G pages. Makes no difference on a 32-bit
system.
(2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value,
lest it overflow.
(3) Move the allocation of the vm_area_struct slab back for fork.c.
(4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs.
(5) Use BUG_ON() rather than if () BUG().
(6) Make the default validate_nommu_regions() a static inline rather than a
#define.
(7) Make free_page_series()'s objection to pages with a refcount != 1 more
informative.
(8) Adjust the __put_nommu_region() banner comment to indicate that the
semaphore must be held for writing.
(9) Limit the number of warnings about munmaps of non-mmapped regions.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index 2fcf47d..72eda4a 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -69,7 +69,7 @@
int sysctl_nr_trim_pages = 1; /* page trimming behaviour */
int heap_stack_gap = 0;
-atomic_t mmap_pages_allocated;
+atomic_long_t mmap_pages_allocated;
EXPORT_SYMBOL(mem_map);
EXPORT_SYMBOL(num_physpages);
@@ -463,12 +463,7 @@
*/
void __init mmap_init(void)
{
- vm_region_jar = kmem_cache_create("vm_region_jar",
- sizeof(struct vm_region), 0,
- SLAB_PANIC, NULL);
- vm_area_cachep = kmem_cache_create("vm_area_struct",
- sizeof(struct vm_area_struct), 0,
- SLAB_PANIC, NULL);
+ vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
}
/*
@@ -486,27 +481,24 @@
return;
last = rb_entry(lastp, struct vm_region, vm_rb);
- if (unlikely(last->vm_end <= last->vm_start))
- BUG();
- if (unlikely(last->vm_top < last->vm_end))
- BUG();
+ BUG_ON(unlikely(last->vm_end <= last->vm_start));
+ BUG_ON(unlikely(last->vm_top < last->vm_end));
while ((p = rb_next(lastp))) {
region = rb_entry(p, struct vm_region, vm_rb);
last = rb_entry(lastp, struct vm_region, vm_rb);
- if (unlikely(region->vm_end <= region->vm_start))
- BUG();
- if (unlikely(region->vm_top < region->vm_end))
- BUG();
- if (unlikely(region->vm_start < last->vm_top))
- BUG();
+ BUG_ON(unlikely(region->vm_end <= region->vm_start));
+ BUG_ON(unlikely(region->vm_top < region->vm_end));
+ BUG_ON(unlikely(region->vm_start < last->vm_top));
lastp = p;
}
}
#else
-#define validate_nommu_regions() do {} while(0)
+static void validate_nommu_regions(void)
+{
+}
#endif
/*
@@ -563,16 +555,17 @@
struct page *page = virt_to_page(from);
kdebug("- free %lx", from);
- atomic_dec(&mmap_pages_allocated);
+ atomic_long_dec(&mmap_pages_allocated);
if (page_count(page) != 1)
- kdebug("free page %p [%d]", page, page_count(page));
+ kdebug("free page %p: refcount not one: %d",
+ page, page_count(page));
put_page(page);
}
}
/*
* release a reference to a region
- * - the caller must hold the region semaphore, which this releases
+ * - the caller must hold the region semaphore for writing, which this releases
* - the region may not have been added to the tree yet, in which case vm_top
* will equal vm_start
*/
@@ -1096,7 +1089,7 @@
goto enomem;
total = 1 << order;
- atomic_add(total, &mmap_pages_allocated);
+ atomic_long_add(total, &mmap_pages_allocated);
point = rlen >> PAGE_SHIFT;
@@ -1107,7 +1100,7 @@
order = ilog2(total - point);
n = 1 << order;
kdebug("shave %lu/%lu @%lu", n, total - point, total);
- atomic_sub(n, &mmap_pages_allocated);
+ atomic_long_sub(n, &mmap_pages_allocated);
total -= n;
set_page_refcounted(pages + total);
__free_pages(pages + total, order);
@@ -1536,10 +1529,15 @@
/* find the first potentially overlapping VMA */
vma = find_vma(mm, start);
if (!vma) {
- printk(KERN_WARNING
- "munmap of memory not mmapped by process %d (%s):"
- " 0x%lx-0x%lx\n",
- current->pid, current->comm, start, start + len - 1);
+ static int limit = 0;
+ if (limit < 5) {
+ printk(KERN_WARNING
+ "munmap of memory not mmapped by process %d"
+ " (%s): 0x%lx-0x%lx\n",
+ current->pid, current->comm,
+ start, start + len - 1);
+ limit++;
+ }
return -EINVAL;
}