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authorLinus Torvalds <torvalds@linux-foundation.org>2009-01-09 14:00:58 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-09 14:00:58 -0800
commitc40f6f8bbc4cbd2902671aacd587400ddca62627 (patch)
treea991e5521e10943f4457fb7f494e00aec75cc7df /mm
parent1a7d0f0bec4be078ce2cfb11538c0f4ffbbed8e5 (diff)
parentcb6ff208076b5f434db1b8c983429269d719cef5 (diff)
downloadlinux-c40f6f8bbc4cbd2902671aacd587400ddca62627.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu: NOMMU: Support XIP on initramfs NOMMU: Teach kobjsize() about VMA regions. FLAT: Don't attempt to expand the userspace stack to fill the space allocated FDPIC: Don't attempt to expand the userspace stack to fill the space allocated NOMMU: Improve procfs output using per-MM VMAs NOMMU: Make mmap allocation page trimming behaviour configurable. NOMMU: Make VMAs per MM as for MMU-mode linux NOMMU: Delete askedalloc and realalloc variables NOMMU: Rename ARM's struct vm_region NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area()
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c10
-rw-r--r--mm/nommu.c1027
2 files changed, 711 insertions, 326 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index a910c045cfd..749623196cb 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2472,3 +2472,13 @@ void mm_drop_all_locks(struct mm_struct *mm)
mutex_unlock(&mm_all_locks_mutex);
}
+
+/*
+ * initialise the VMA slab
+ */
+void __init mmap_init(void)
+{
+ vm_area_cachep = kmem_cache_create("vm_area_struct",
+ sizeof(struct vm_area_struct), 0,
+ SLAB_PANIC, NULL);
+}
diff --git a/mm/nommu.c b/mm/nommu.c
index 1c28ea3a4e9..60ed8375c98 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -6,11 +6,11 @@
*
* See Documentation/nommu-mmap.txt
*
- * Copyright (c) 2004-2005 David Howells <dhowells@redhat.com>
+ * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
* Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
* Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
* Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
- * Copyright (c) 2007 Paul Mundt <lethal@linux-sh.org>
+ * Copyright (c) 2007-2008 Paul Mundt <lethal@linux-sh.org>
*/
#include <linux/module.h>
@@ -33,6 +33,28 @@
#include <asm/uaccess.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
+#include "internal.h"
+
+static inline __attribute__((format(printf, 1, 2)))
+void no_printk(const char *fmt, ...)
+{
+}
+
+#if 0
+#define kenter(FMT, ...) \
+ printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+ printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
+#else
+#define kenter(FMT, ...) \
+ no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+ no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
+#endif
#include "internal.h"
@@ -40,19 +62,22 @@ void *high_memory;
struct page *mem_map;
unsigned long max_mapnr;
unsigned long num_physpages;
-unsigned long askedalloc, realalloc;
atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
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_nr_trim_pages = 1; /* page trimming behaviour */
int heap_stack_gap = 0;
+atomic_t mmap_pages_allocated;
+
EXPORT_SYMBOL(mem_map);
EXPORT_SYMBOL(num_physpages);
-/* list of shareable VMAs */
-struct rb_root nommu_vma_tree = RB_ROOT;
-DECLARE_RWSEM(nommu_vma_sem);
+/* list of mapped, potentially shareable regions */
+static struct kmem_cache *vm_region_jar;
+struct rb_root nommu_region_tree = RB_ROOT;
+DECLARE_RWSEM(nommu_region_sem);
struct vm_operations_struct generic_file_vm_ops = {
};
@@ -124,6 +149,20 @@ unsigned int kobjsize(const void *objp)
return ksize(objp);
/*
+ * If it's not a compound page, see if we have a matching VMA
+ * region. This test is intentionally done in reverse order,
+ * so if there's no VMA, we still fall through and hand back
+ * PAGE_SIZE for 0-order pages.
+ */
+ if (!PageCompound(page)) {
+ struct vm_area_struct *vma;
+
+ vma = find_vma(current->mm, (unsigned long)objp);
+ if (vma)
+ return vma->vm_end - vma->vm_start;
+ }
+
+ /*
* The ksize() function is only guaranteed to work for pointers
* returned by kmalloc(). So handle arbitrary pointers here.
*/
@@ -401,129 +440,178 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
return mm->brk = brk;
}
-#ifdef DEBUG
-static void show_process_blocks(void)
+/*
+ * initialise the VMA and region record slabs
+ */
+void __init mmap_init(void)
{
- struct vm_list_struct *vml;
-
- printk("Process blocks %d:", current->pid);
-
- for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
- printk(" %p: %p", vml, vml->vma);
- if (vml->vma)
- printk(" (%d @%lx #%d)",
- kobjsize((void *) vml->vma->vm_start),
- vml->vma->vm_start,
- atomic_read(&vml->vma->vm_usage));
- printk(vml->next ? " ->" : ".\n");
- }
+ 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);
}
-#endif /* DEBUG */
/*
- * add a VMA into a process's mm_struct in the appropriate place in the list
- * - should be called with mm->mmap_sem held writelocked
+ * validate the region tree
+ * - the caller must hold the region lock
*/
-static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
+#ifdef CONFIG_DEBUG_NOMMU_REGIONS
+static noinline void validate_nommu_regions(void)
{
- struct vm_list_struct **ppv;
-
- for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
- if ((*ppv)->vma->vm_start > vml->vma->vm_start)
- break;
-
- vml->next = *ppv;
- *ppv = vml;
+ struct vm_region *region, *last;
+ struct rb_node *p, *lastp;
+
+ lastp = rb_first(&nommu_region_tree);
+ if (!lastp)
+ 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();
+
+ 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();
+
+ lastp = p;
+ }
}
+#else
+#define validate_nommu_regions() do {} while(0)
+#endif
/*
- * look up the first VMA in which addr resides, NULL if none
- * - should be called with mm->mmap_sem at least held readlocked
+ * add a region into the global tree
*/
-struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+static void add_nommu_region(struct vm_region *region)
{
- struct vm_list_struct *loop, *vml;
+ struct vm_region *pregion;
+ struct rb_node **p, *parent;
- /* search the vm_start ordered list */
- vml = NULL;
- for (loop = mm->context.vmlist; loop; loop = loop->next) {
- if (loop->vma->vm_start > addr)
- break;
- vml = loop;
+ validate_nommu_regions();
+
+ BUG_ON(region->vm_start & ~PAGE_MASK);
+
+ parent = NULL;
+ p = &nommu_region_tree.rb_node;
+ while (*p) {
+ parent = *p;
+ pregion = rb_entry(parent, struct vm_region, vm_rb);
+ if (region->vm_start < pregion->vm_start)
+ p = &(*p)->rb_left;
+ else if (region->vm_start > pregion->vm_start)
+ p = &(*p)->rb_right;
+ else if (pregion == region)
+ return;
+ else
+ BUG();
}
- if (vml && vml->vma->vm_end > addr)
- return vml->vma;
+ rb_link_node(&region->vm_rb, parent, p);
+ rb_insert_color(&region->vm_rb, &nommu_region_tree);
- return NULL;
+ validate_nommu_regions();
}
-EXPORT_SYMBOL(find_vma);
/*
- * find a VMA
- * - we don't extend stack VMAs under NOMMU conditions
+ * delete a region from the global tree
*/
-struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
+static void delete_nommu_region(struct vm_region *region)
{
- return find_vma(mm, addr);
-}
+ BUG_ON(!nommu_region_tree.rb_node);
-int expand_stack(struct vm_area_struct *vma, unsigned long address)
-{
- return -ENOMEM;
+ validate_nommu_regions();
+ rb_erase(&region->vm_rb, &nommu_region_tree);
+ validate_nommu_regions();
}
/*
- * look up the first VMA exactly that exactly matches addr
- * - should be called with mm->mmap_sem at least held readlocked
+ * free a contiguous series of pages
*/
-static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
- unsigned long addr)
+static void free_page_series(unsigned long from, unsigned long to)
{
- struct vm_list_struct *vml;
-
- /* search the vm_start ordered list */
- for (vml = mm->context.vmlist; vml; vml = vml->next) {
- if (vml->vma->vm_start == addr)
- return vml->vma;
- if (vml->vma->vm_start > addr)
- break;
+ for (; from < to; from += PAGE_SIZE) {
+ struct page *page = virt_to_page(from);
+
+ kdebug("- free %lx", from);
+ atomic_dec(&mmap_pages_allocated);
+ if (page_count(page) != 1)
+ kdebug("free page %p [%d]", page, page_count(page));
+ put_page(page);
}
-
- return NULL;
}
/*
- * find a VMA in the global tree
+ * release a reference to a region
+ * - the caller must hold the region semaphore, which this releases
+ * - the region may not have been added to the tree yet, in which case vm_top
+ * will equal vm_start
*/
-static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
+static void __put_nommu_region(struct vm_region *region)
+ __releases(nommu_region_sem)
{
- struct vm_area_struct *vma;
- struct rb_node *n = nommu_vma_tree.rb_node;
+ kenter("%p{%d}", region, atomic_read(&region->vm_usage));
- while (n) {
- vma = rb_entry(n, struct vm_area_struct, vm_rb);
+ BUG_ON(!nommu_region_tree.rb_node);
- if (start < vma->vm_start)
- n = n->rb_left;
- else if (start > vma->vm_start)
- n = n->rb_right;
- else
- return vma;
+ if (atomic_dec_and_test(&region->vm_usage)) {
+ if (region->vm_top > region->vm_start)
+ delete_nommu_region(region);
+ up_write(&nommu_region_sem);
+
+ if (region->vm_file)
+ fput(region->vm_file);
+
+ /* IO memory and memory shared directly out of the pagecache
+ * from ramfs/tmpfs mustn't be released here */
+ if (region->vm_flags & VM_MAPPED_COPY) {
+ kdebug("free series");
+ free_page_series(region->vm_start, region->vm_top);
+ }
+ kmem_cache_free(vm_region_jar, region);
+ } else {
+ up_write(&nommu_region_sem);
}
+}
- return NULL;
+/*
+ * release a reference to a region
+ */
+static void put_nommu_region(struct vm_region *region)
+{
+ down_write(&nommu_region_sem);
+ __put_nommu_region(region);
}
/*
- * add a VMA in the global tree
+ * add a VMA into a process's mm_struct in the appropriate place in the list
+ * and tree and add to the address space's page tree also if not an anonymous
+ * page
+ * - should be called with mm->mmap_sem held writelocked
*/
-static void add_nommu_vma(struct vm_area_struct *vma)
+static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
- struct vm_area_struct *pvma;
+ struct vm_area_struct *pvma, **pp;
struct address_space *mapping;
- struct rb_node **p = &nommu_vma_tree.rb_node;
- struct rb_node *parent = NULL;
+ struct rb_node **p, *parent;
+
+ kenter(",%p", vma);
+
+ BUG_ON(!vma->vm_region);
+
+ mm->map_count++;
+ vma->vm_mm = mm;
/* add the VMA to the mapping */
if (vma->vm_file) {
@@ -534,42 +622,62 @@ static void add_nommu_vma(struct vm_area_struct *vma)
flush_dcache_mmap_unlock(mapping);
}
- /* add the VMA to the master list */
+ /* add the VMA to the tree */
+ parent = NULL;
+ p = &mm->mm_rb.rb_node;
while (*p) {
parent = *p;
pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
- if (vma->vm_start < pvma->vm_start) {
+ /* sort by: start addr, end addr, VMA struct addr in that order
+ * (the latter is necessary as we may get identical VMAs) */
+ if (vma->vm_start < pvma->vm_start)
p = &(*p)->rb_left;
- }
- else if (vma->vm_start > pvma->vm_start) {
+ else if (vma->vm_start > pvma->vm_start)
p = &(*p)->rb_right;
- }
- else {
- /* mappings are at the same address - this can only
- * happen for shared-mem chardevs and shared file
- * mappings backed by ramfs/tmpfs */
- BUG_ON(!(pvma->vm_flags & VM_SHARED));
-
- if (vma < pvma)
- p = &(*p)->rb_left;
- else if (vma > pvma)
- p = &(*p)->rb_right;
- else
- BUG();
- }
+ else if (vma->vm_end < pvma->vm_end)
+ p = &(*p)->rb_left;
+ else if (vma->vm_end > pvma->vm_end)
+ p = &(*p)->rb_right;
+ else if (vma < pvma)
+ p = &(*p)->rb_left;
+ else if (vma > pvma)
+ p = &(*p)->rb_right;
+ else
+ BUG();
}
rb_link_node(&vma->vm_rb, parent, p);
- rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
+ rb_insert_color(&vma->vm_rb, &mm->mm_rb);
+
+ /* add VMA to the VMA list also */
+ for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
+ if (pvma->vm_start > vma->vm_start)
+ break;
+ if (pvma->vm_start < vma->vm_start)
+ continue;
+ if (pvma->vm_end < vma->vm_end)
+ break;
+ }
+
+ vma->vm_next = *pp;
+ *pp = vma;
}
/*
- * delete a VMA from the global list
+ * delete a VMA from its owning mm_struct and address space
*/
-static void delete_nommu_vma(struct vm_area_struct *vma)
+static void delete_vma_from_mm(struct vm_area_struct *vma)
{
+ struct vm_area_struct **pp;
struct address_space *mapping;
+ struct mm_struct *mm = vma->vm_mm;
+
+ kenter("%p", vma);
+
+ mm->map_count--;
+ if (mm->mmap_cache == vma)
+ mm->mmap_cache = NULL;
/* remove the VMA from the mapping */
if (vma->vm_file) {
@@ -580,8 +688,115 @@ static void delete_nommu_vma(struct vm_area_struct *vma)
flush_dcache_mmap_unlock(mapping);
}
- /* remove from the master list */
- rb_erase(&vma->vm_rb, &nommu_vma_tree);
+ /* remove from the MM's tree and list */
+ rb_erase(&vma->vm_rb, &mm->mm_rb);
+ for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
+ if (*pp == vma) {
+ *pp = vma->vm_next;
+ break;
+ }
+ }
+
+ vma->vm_mm = NULL;
+}
+
+/*
+ * destroy a VMA record
+ */
+static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+ kenter("%p", vma);
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+ if (vma->vm_file) {
+ fput(vma->vm_file);
+ if (vma->vm_flags & VM_EXECUTABLE)
+ removed_exe_file_vma(mm);
+ }
+ put_nommu_region(vma->vm_region);
+ kmem_cache_free(vm_area_cachep, vma);
+}
+
+/*
+ * look up the first VMA in which addr resides, NULL if none
+ * - should be called with mm->mmap_sem at least held readlocked
+ */
+struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+{
+ struct vm_area_struct *vma;
+ struct rb_node *n = mm->mm_rb.rb_node;
+
+ /* check the cache first */
+ vma = mm->mmap_cache;
+ if (vma && vma->vm_start <= addr && vma->vm_end > addr)
+ return vma;
+
+ /* trawl the tree (there may be multiple mappings in which addr
+ * resides) */
+ for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
+ vma = rb_entry(n, struct vm_area_struct, vm_rb);
+ if (vma->vm_start > addr)
+ return NULL;
+ if (vma->vm_end > addr) {
+ mm->mmap_cache = vma;
+ return vma;
+ }
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(find_vma);
+
+/*
+ * find a VMA
+ * - we don't extend stack VMAs under NOMMU conditions
+ */
+struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
+{
+ return find_vma(mm, addr);
+}
+
+/*
+ * expand a stack to a given address
+ * - not supported under NOMMU conditions
+ */
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+ return -ENOMEM;
+}
+
+/*
+ * look up the first VMA exactly that exactly matches addr
+ * - should be called with mm->mmap_sem at least held readlocked
+ */
+static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
+ unsigned long addr,
+ unsigned long len)
+{
+ struct vm_area_struct *vma;
+ struct rb_node *n = mm->mm_rb.rb_node;
+ unsigned long end = addr + len;
+
+ /* check the cache first */
+ vma = mm->mmap_cache;
+ if (vma && vma->vm_start == addr && vma->vm_end == end)
+ return vma;
+
+ /* trawl the tree (there may be multiple mappings in which addr
+ * resides) */
+ for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
+ vma = rb_entry(n, struct vm_area_struct, vm_rb);
+ if (vma->vm_start < addr)
+ continue;
+ if (vma->vm_start > addr)
+ return NULL;
+ if (vma->vm_end == end) {
+ mm->mmap_cache = vma;
+ return vma;
+ }
+ }
+
+ return NULL;
}
/*
@@ -596,7 +811,7 @@ static int validate_mmap_request(struct file *file,
unsigned long pgoff,
unsigned long *_capabilities)
{
- unsigned long capabilities;
+ unsigned long capabilities, rlen;
unsigned long reqprot = prot;
int ret;
@@ -616,12 +831,12 @@ static int validate_mmap_request(struct file *file,
return -EINVAL;
/* Careful about overflows.. */
- len = PAGE_ALIGN(len);
- if (!len || len > TASK_SIZE)
+ rlen = PAGE_ALIGN(len);
+ if (!rlen || rlen > TASK_SIZE)
return -ENOMEM;
/* offset overflow? */
- if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
+ if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
return -EOVERFLOW;
if (file) {
@@ -795,13 +1010,18 @@ static unsigned long determine_vm_flags(struct file *file,
}
/*
- * set up a shared mapping on a file
+ * set up a shared mapping on a file (the driver or filesystem provides and
+ * pins the storage)
*/
-static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
+static int do_mmap_shared_file(struct vm_area_struct *vma)
{
int ret;
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+ if (ret == 0) {
+ vma->vm_region->vm_top = vma->vm_region->vm_end;
+ return ret;
+ }
if (ret != -ENOSYS)
return ret;
@@ -815,10 +1035,14 @@ static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
/*
* set up a private mapping or an anonymous shared mapping
*/
-static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
+static int do_mmap_private(struct vm_area_struct *vma,
+ struct vm_region *region,
+ unsigned long len)
{
+ struct page *pages;
+ unsigned long total, point, n, rlen;
void *base;
- int ret;
+ int ret, order;
/* invoke the file's mapping function so that it can keep track of
* shared mappings on devices or memory
@@ -826,34 +1050,63 @@ static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
*/
if (vma->vm_file) {
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
- if (ret != -ENOSYS) {
+ if (ret == 0) {
/* shouldn't return success if we're not sharing */
- BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
- return ret; /* success or a real error */
+ BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
+ vma->vm_region->vm_top = vma->vm_region->vm_end;
+ return ret;
}
+ if (ret != -ENOSYS)
+ return ret;
/* getting an ENOSYS error indicates that direct mmap isn't
* possible (as opposed to tried but failed) so we'll try to
* make a private copy of the data and map that instead */
}
+ rlen = PAGE_ALIGN(len);
+
/* allocate some memory to hold the mapping
* - note that this may not return a page-aligned address if the object
* we're allocating is smaller than a page
*/
- base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
- if (!base)
+ order = get_order(rlen);
+ kdebug("alloc order %d for %lx", order, len);
+
+ pages = alloc_pages(GFP_KERNEL, order);
+ if (!pages)
goto enomem;
- vma->vm_start = (unsigned long) base;
- vma->vm_end = vma->vm_start + len;
- vma->vm_flags |= VM_MAPPED_COPY;
+ total = 1 << order;
+ atomic_add(total, &mmap_pages_allocated);
+
+ point = rlen >> PAGE_SHIFT;
+
+ /* we allocated a power-of-2 sized page set, so we may want to trim off
+ * the excess */
+ if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
+ while (total > point) {
+ order = ilog2(total - point);
+ n = 1 << order;
+ kdebug("shave %lu/%lu @%lu", n, total - point, total);
+ atomic_sub(n, &mmap_pages_allocated);
+ total -= n;
+ set_page_refcounted(pages + total);
+ __free_pages(pages + total, order);
+ }
+ }
+
+ for (point = 1; point < total; point++)
+ set_page_refcounted(&pages[point]);
-#ifdef WARN_ON_SLACK
- if (len + WARN_ON_SLACK <= kobjsize(result))
- printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
- len, current->pid, kobjsize(result) - len);
-#endif
+ base = page_address(pages);
+ region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
+ region->vm_start = (unsigned long) base;
+ region->vm_end = region->vm_start + rlen;
+ region->vm_top = region->vm_start + (total << PAGE_SHIFT);
+
+ vma->vm_start = region->vm_start;
+ vma->vm_end = region->vm_start + len;
if (vma->vm_file) {
/* read the contents of a file into the copy */
@@ -865,26 +1118,28 @@ static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
old_fs = get_fs();
set_fs(KERNEL_DS);
- ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
+ ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
set_fs(old_fs);
if (ret < 0)
goto error_free;
/* clear the last little bit */
- if (ret < len)
- memset(base + ret, 0, len - ret);
+ if (ret < rlen)
+ memset(base + ret, 0, rlen - ret);
} else {
/* if it's an anonymous mapping, then just clear it */
- memset(base, 0, len);
+ memset(base, 0, rlen);
}
return 0;
error_free:
- kfree(base);
- vma->vm_start = 0;
+ free_page_series(region->vm_start, region->vm_end);
+ region->vm_start = vma->vm_start = 0;
+ region->vm_end = vma->vm_end = 0;
+ region->vm_top = 0;
return ret;
enomem:
@@ -904,13 +1159,14 @@ unsigned long do_mmap_pgoff(struct file *file,
unsigned long flags,
unsigned long pgoff)
{
- struct vm_list_struct *vml = NULL;
- struct vm_area_struct *vma = NULL;
+ struct vm_area_struct *vma;
+ struct vm_region *region;
struct rb_node *rb;
- unsigned long capabilities, vm_flags;
- void *result;
+ unsigned long capabilities, vm_flags, result;
int ret;
+ kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
+
if (!(flags & MAP_FIXED))
addr = round_hint_to_min(addr);
@@ -918,73 +1174,120 @@ unsigned long do_mmap_pgoff(struct file *file,
* mapping */
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
&capabilities);
- if (ret < 0)
+ if (ret < 0) {
+ kleave(" = %d [val]", ret);
return ret;
+ }
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
vm_flags = determine_vm_flags(file, prot, flags, capabilities);
- /* we're going to need to record the mapping if it works */
- vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
- if (!vml)
- goto error_getting_vml;
+ /* we're going to need to record the mapping */
+ region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
+ if (!region)
+ goto error_getting_region;
+
+ vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+ if (!vma)
+ goto error_getting_vma;
+
+ atomic_set(&region->vm_usage, 1);
+ region->vm_flags = vm_flags;
+ region->vm_pgoff = pgoff;
+
+ INIT_LIST_HEAD(&vma->anon_vma_node);
+ vma->vm_flags = vm_flags;
+ vma->vm_pgoff = pgoff;
- down_write(&nommu_vma_sem);
+ if (file) {
+ region->vm_file = file;
+ get_file(file);
+ vma->vm_file = file;
+ get_file(file);
+ if (vm_flags & VM_EXECUTABLE) {
+ added_exe_file_vma(current->mm);
+ vma->vm_mm = current->mm;
+ }
+ }
- /* if we want to share, we need to check for VMAs created by other
+ down_write(&nommu_region_sem);
+
+ /* if we want to share, we need to check for regions created by other
* mmap() calls that overlap with our proposed mapping
- * - we can only share with an exact match on most regular files
+ * - we can only share with a superset match on most regular files
* - shared mappings on character devices and memory backed files are
* permitted to overlap inexactly as far as we are concerned for in
* these cases, sharing is handled in the driver or filesystem rather
* than here
*/
if (vm_flags & VM_MAYSHARE) {
- unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned long vmpglen;
+ struct vm_region *pregion;
+ unsigned long pglen, rpglen, pgend, rpgend, start;
- /* suppress VMA sharing for shared regions */
- if (vm_flags & VM_SHARED &&
- capabilities & BDI_CAP_MAP_DIRECT)
- goto dont_share_VMAs;
+ pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ pgend = pgoff + pglen;
- for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
- vma = rb_entry(rb, struct vm_area_struct, vm_rb);
+ for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
+ pregion = rb_entry(rb, struct vm_region, vm_rb);
- if (!(vma->vm_flags & VM_MAYSHARE))
+ if (!(pregion->vm_flags & VM_MAYSHARE))
continue;
/* search for overlapping mappings on the same file */
- if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
+ if (pregion->vm_file->f_path.dentry->d_inode !=
+ file->f_path.dentry->d_inode)
continue;
- if (vma->vm_pgoff >= pgoff + pglen)
+ if (pregion->vm_pgoff >= pgend)
continue;
- vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
- vmpglen >>= PAGE_SHIFT;
- if (pgoff >= vma->vm_pgoff + vmpglen)
+ rpglen = pregion->vm_end - pregion->vm_start;
+ rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ rpgend = pregion->vm_pgoff + rpglen;
+ if (pgoff >= rpgend)
continue;
- /* handle inexactly overlapping matches between mappings */
- if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
+ /* handle inexactly overlapping matches between
+ * mappings */
+ if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
+ !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
+ /* new mapping is not a subset of the region */
if (!(capabilities & BDI_CAP_MAP_DIRECT))
goto sharing_violation;
continue;
}
- /* we've found a VMA we can share */
- atomic_inc(&vma->vm_usage);
-
- vml->vma = vma;
- result = (void *) vma->vm_start;
- goto shared;
+ /* we've found a region we can share */
+ atomic_inc(&pregion->vm_usage);
+ vma->vm_region = pregion;
+ start = pregion->vm_start;
+ start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
+ vma->vm_start = start;
+ vma->vm_end = start + len;
+
+ if (pregion->vm_flags & VM_MAPPED_COPY) {
+ kdebug("share copy");
+ vma->vm_flags |= VM_MAPPED_COPY;
+ } else {
+ kdebug("share mmap");
+ ret = do_mmap_shared_file(vma);
+ if (ret < 0) {
+ vma->vm_region = NULL;
+ vma->vm_start = 0;
+ vma->vm_end = 0;
+ atomic_dec(&pregion->vm_usage);
+ pregion = NULL;
+ goto error_just_free;
+ }
+ }
+ fput(region->vm_file);
+ kmem_cache_free(vm_region_jar, region);
+ region = pregion;
+ result = start;
+ goto share;
}
- dont_share_VMAs:
- vma = NULL;
-
/* obtain the address at which to make a shared mapping
* - this is the hook for quasi-memory character devices to
* tell us the location of a shared mapping
@@ -995,113 +1298,93 @@ unsigned long do_mmap_pgoff(struct file *file,
if (IS_ERR((void *) addr)) {
ret = addr;
if (ret != (unsigned long) -ENOSYS)
- goto error;
+ goto error_just_free;
/* the driver refused to tell us where to site
* the mapping so we'll have to attempt to copy
* it */
ret = (unsigned long) -ENODEV;
if (!(capabilities & BDI_CAP_MAP_COPY))
- goto error;
+ goto error_just_free;
capabilities &= ~BDI_CAP_MAP_DIRECT;
+ } else {
+ vma->vm_start = region->vm_start = addr;
+ vma->vm_end = region->vm_end = addr + len;
}
}
}
- /* we're going to need a VMA struct as well */
- vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
- if (!vma)
- goto error_getting_vma;
-
- INIT_LIST_HEAD(&vma->anon_vma_node);
- atomic_set(&vma->vm_usage, 1);
- if (file) {
- get_file(file);
- if (vm_flags & VM_EXECUTABLE) {
- added_exe_file_vma(current->mm);
- vma->vm_mm = current->mm;
- }
- }
- vma->vm_file = file;
- vma->vm_flags = vm_flags;
- vma->vm_start = addr;
- vma->vm_end = addr + len;
- vma->vm_pgoff = pgoff;
-
- vml->vma = vma;
+ vma->vm_region = region;
/* set up the mapping */
if (file && vma->vm_flags & VM_SHARED)
- ret = do_mmap_shared_file(vma, len);
+ ret = do_mmap_shared_file(vma);
else
- ret = do_mmap_private(vma, len);
+ ret = do_mmap_private(vma, region, len);
if (ret < 0)
- goto error;
-
- /* okay... we have a mapping; now we have to register it */
- result = (void *) vma->vm_start;
+ goto error_put_region;
- if (vma->vm_flags & VM_MAPPED_COPY) {
- realalloc += kobjsize(result);
- askedalloc += len;
- }
+ add_nommu_region(region);
- realalloc += kobjsize(vma);
- askedalloc += sizeof(*vma);
+ /* okay... we have a mapping; now we have to register it */
+ result = vma->vm_start;
current->mm->total_vm += len >> PAGE_SHIFT;
- add_nommu_vma(vma);
-
- shared:
- realalloc += kobjsize(vml);
- askedalloc += sizeof(*vml);
-
- add_vma_to_mm(current->mm, vml);
+share:
+ add_vma_to_mm(current->mm, vma);
- up_write(&nommu_vma_sem);
+ up_write(&nommu_region_sem);
if (prot & PROT_EXEC)
- flush_icache_range((unsigned long) result,
- (unsigned long) result + len);
+ flush_icache_range(result, result + len);
-#ifdef DEBUG
- printk("do_mmap:\n");
- show_process_blocks();
-#endif
-
- return (unsigned long) result;
+ kleave(" = %lx", result);
+ return result;
- error:
- up_write(&nommu_vma_sem);
- kfree(vml);
+error_put_region:
+ __put_nommu_region(region);
if (vma) {
if (vma->vm_file) {
fput(vma->vm_file);
if (vma->vm_flags & VM_EXECUTABLE)
removed_exe_file_vma(vma->vm_mm);
}
- kfree(vma);
+ kmem_cache_free(vm_area_cachep, vma);
}
+ kleave(" = %d [pr]", ret);
return ret;
- sharing_violation:
- up_write(&nommu_vma_sem);
- printk("Attempt to share mismatched mappings\n");
- kfree(vml);
- return -EINVAL;
+error_just_free:
+ up_write(&nommu_region_sem);
+error:
+ fput(region->vm_file);
+ kmem_cache_free(vm_region_jar, region);
+ fput(vma->vm_file);
+ if (vma->vm_flags & VM_EXECUTABLE)
+ removed_exe_file_vma(vma->vm_mm);
+ kmem_cache_free(vm_area_cachep, vma);
+ kleave(" = %d", ret);
+ return ret;
- error_getting_vma:
- up_write(&nommu_vma_sem);
- kfree(vml);
- printk("Allocation of vma for %lu byte allocation from process %d failed\n",
+sharing_violation:
+ up_write(&nommu_region_sem);
+ printk(KERN_WARNING "Attempt to share mismatched mappings\n");
+ ret = -EINVAL;
+ goto error;
+
+error_getting_vma:
+ kmem_cache_free(vm_region_jar, region);
+ printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
+ " from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
- error_getting_vml:
- printk("Allocation of vml for %lu byte allocation from process %d failed\n",
+error_getting_region:
+ printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
+ " from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
@@ -1109,85 +1392,183 @@ unsigned long do_mmap_pgoff(struct file *file,
EXPORT_SYMBOL(do_mmap_pgoff);
/*
- * handle mapping disposal for uClinux
+ * split a vma into two pieces at address 'addr', a new vma is allocated either
+ * for the first part or the tail.
*/
-static void put_vma(struct mm_struct *mm, struct vm_area_struct *vma)
+int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
{
- if (vma) {
- down_write(&nommu_vma_sem);
+ struct vm_area_struct *new;
+ struct vm_region *region;
+ unsigned long npages;
- if (atomic_dec_and_test(&vma->vm_usage)) {
- delete_nommu_vma(vma);
+ kenter("");
- if (vma->vm_ops && vma->vm_ops->close)
- vma->vm_ops->close(vma);
+ /* we're only permitted to split anonymous regions that have a single
+ * owner */
+ if (vma->vm_file ||
+ atomic_read(&vma->vm_region->vm_usage) != 1)
+ return -ENOMEM;
- /* IO memory and memory shared directly out of the pagecache from
- * ramfs/tmpfs mustn't be released here */
- if (vma->vm_flags & VM_MAPPED_COPY) {
- realalloc -= kobjsize((void *) vma->vm_start);
- askedalloc -= vma->vm_end - vma->vm_start;
- kfree((void *) vma->vm_start);
- }
+ if (mm->map_count >= sysctl_max_map_count)
+ return -ENOMEM;
- realalloc -= kobjsize(vma);
- askedalloc -= sizeof(*vma);
+ region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
+ if (!region)
+ return -ENOMEM;
- if (vma->vm_file) {
- fput(vma->vm_file);
- if (vma->vm_flags & VM_EXECUTABLE)
- removed_exe_file_vma(mm);
- }
- kfree(vma);
- }
+ new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+ if (!new) {
+ kmem_cache_free(vm_region_jar, region);
+ return -ENOMEM;
+ }
+
+ /* most fields are the same, copy all, and then fixup */
+ *new = *vma;
+ *region = *vma->vm_region;
+ new->vm_region = region;
+
+ npages = (addr - vma->vm_start) >> PAGE_SHIFT;
- up_write(&nommu_vma_sem);
+ if (new_below) {
+ region->vm_top = region->vm_end = new->vm_end = addr;
+ } else {
+ region->vm_start = new->vm_start = addr;
+ region->vm_pgoff = new->vm_pgoff += npages;
+ }
+
+ if (new->vm_ops && new->vm_ops->open)
+ new->vm_ops->open(new);
+
+ delete_vma_from_mm(vma);
+ down_write(&nommu_region_sem);
+ delete_nommu_region(vma->vm_region);
+ if (new_below) {
+ vma->vm_region->vm_start = vma->vm_start = addr;
+ vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
+ } else {
+ vma->vm_region->vm_end = vma->vm_end = addr;
+ vma->vm_region->vm_top = addr;
}
+ add_nommu_region(vma->vm_region);
+ add_nommu_region(new->vm_region);
+ up_write(&nommu_region_sem);
+ add_vma_to_mm(mm, vma);
+ add_vma_to_mm(mm, new);
+ return 0;
}
/*
- * release a mapping
- * - under NOMMU conditions the parameters must match exactly to the mapping to
- * be removed
+ * shrink a VMA by removing the specified chunk from either the beginning or
+ * the end
*/
-int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
+static int shrink_vma(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long from, unsigned long to)
{
- struct vm_list_struct *vml, **parent;
- unsigned long end = addr + len;
+ struct vm_region *region;
-#ifdef DEBUG
- printk("do_munmap:\n");
-#endif
+ kenter("");
- for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
- if ((*parent)->vma->vm_start > addr)
- break;
- if ((*parent)->vma->vm_start == addr &&
- ((len == 0) || ((*parent)->vma->vm_end == end)))
- goto found;
+ /* adjust the VMA's pointers, which may reposition it in the MM's tree
+ * and list */
+ delete_vma_from_mm(vma);
+ if (from > vma->vm_start)
+ vma->vm_end = from;
+ else
+ vma->vm_start = to;
+ add_vma_to_mm(mm, vma);
+
+ /* cut the backing region down to size */
+ region = vma->vm_region;
+ BUG_ON(atomic_read(&region->vm_usage) != 1);
+
+ down_write(&nommu_region_sem);
+ delete_nommu_region(region);
+ if (from > region->vm_start) {
+ to = region->vm_top;
+ region->vm_top = region->vm_end = from;
+ } else {
+ region->vm_start = to;
}
+ add_nommu_region(region);
+ up_write(&nommu_region_sem);
- printk("munmap of non-mmaped memory by process %d (%s): %p\n",
- current->pid, current->comm, (void *) addr);
- return -EINVAL;
+ free_page_series(from, to);
+ return 0;
+}
- found:
- vml = *parent;
+/*
+ * release a mapping
+ * - under NOMMU conditions the chunk to be unmapped must be backed by a single
+ * VMA, though it need not cover the whole VMA
+ */
+int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
+{
+ struct vm_area_struct *vma;
+ struct rb_node *rb;
+ unsigned long end = start + len;
+ int ret;
- put_vma(mm, vml->vma);
+ kenter(",%lx,%zx", start, len);
- *parent = vml->next;
- realalloc -= kobjsize(vml);
- askedalloc -= sizeof(*vml);
- kfree(vml);
+ if (len == 0)
+ return -EINVAL;
- update_hiwater_vm(mm);
- mm->total_vm -= len >> PAGE_SHIFT;
+ /* 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);
+ return -EINVAL;
+ }
-#ifdef DEBUG
- show_process_blocks();
-#endif
+ /* we're allowed to split an anonymous VMA but not a file-backed one */
+ if (vma->vm_file) {
+ do {
+ if (start > vma->vm_start) {
+ kleave(" = -EINVAL [miss]");
+ return -EINVAL;
+ }
+ if (end == vma->vm_end)
+ goto erase_whole_vma;
+ rb = rb_next(&vma->vm_rb);
+ vma = rb_entry(rb, struct vm_area_struct, vm_rb);
+ } while (rb);
+ kleave(" = -EINVAL [split file]");
+ return -EINVAL;
+ } else {
+ /* the chunk must be a subset of the VMA found */
+ if (start == vma->vm_start && end == vma->vm_end)
+ goto erase_whole_vma;
+ if (start < vma->vm_start || end > vma->vm_end) {
+ kleave(" = -EINVAL [superset]");
+ return -EINVAL;
+ }
+ if (start & ~PAGE_MASK) {
+ kleave(" = -EINVAL [unaligned start]");
+ return -EINVAL;
+ }
+ if (end != vma->vm_end && end & ~PAGE_MASK) {
+ kleave(" = -EINVAL [unaligned split]");
+ return -EINVAL;
+ }
+ if (start != vma->vm_start && end != vma->vm_end) {
+ ret = split_vma(mm, vma, start, 1);
+ if (ret < 0) {
+ kleave(" = %d [split]", ret);
+ return ret;
+ }
+ }
+ return shrink_vma(mm, vma, start, end);
+ }
+erase_whole_vma:
+ delete_vma_from_mm(vma);
+ delete_vma(mm, vma);
+ kleave(" = 0");
return 0;
}
EXPORT_SYMBOL(do_munmap);
@@ -1204,32 +1585,26 @@ asmlinkage long sys_munmap(unsigned long addr, size_t len)
}
/*
- * Release all mappings
+ * release all the mappings made in a process's VM space
*/
-void exit_mmap(struct mm_struct * mm)
+void exit_mmap(struct mm_struct *mm)
{
- struct vm_list_struct *tmp;
-
- if (mm) {
-#ifdef DEBUG
- printk("Exit_mmap:\n");
-#endif
+ struct vm_area_struct *vma;
- mm->total_vm = 0;
+ if (!mm)
+ return;
- while ((tmp = mm->context.vmlist)) {
- mm->context.vmlist = tmp->next;
- put_vma(mm, tmp->vma);
+ kenter("");
- realalloc -= kobjsize(tmp);
- askedalloc -= sizeof(*tmp);
- kfree(tmp);
- }
+ mm->total_vm = 0;
-#ifdef DEBUG
- show_process_blocks();
-#endif
+ while ((vma = mm->mmap)) {
+ mm->mmap = vma->vm_next;
+ delete_vma_from_mm(vma);
+ delete_vma(mm, vma);
}
+
+ kleave("");
}
unsigned long do_brk(unsigned long addr, unsigned long len)
@@ -1242,8 +1617,8 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
* time (controlled by the MREMAP_MAYMOVE flag and available VM space)
*
* under NOMMU conditions, we only permit changing a mapping's size, and only
- * as long as it stays within the hole allocated by the kmalloc() call in
- * do_mmap_pgoff() and the block is not shareable
+ * as long as it stays within the region allocated by do_mmap_private() and the
+ * block is not shareable
*
* MREMAP_FIXED is not supported under NOMMU conditions
*/
@@ -1254,13 +1629,16 @@ unsigned long do_mremap(unsigned long addr,
struct vm_area_struct *vma;
/* insanity checks first */
- if (new_len == 0)
+ if (old_len == 0 || new_len == 0)
return (unsigned long) -EINVAL;
+ if (addr & ~PAGE_MASK)
+ return -EINVAL;
+
if (flags & MREMAP_FIXED && new_addr != addr)
return (unsigned long) -EINVAL;
- vma = find_vma_exact(current->mm, addr);
+ vma = find_vma_exact(current->mm, addr, old_len);
if (!vma)
return (unsigned long) -EINVAL;
@@ -1270,22 +1648,19 @@ unsigned long do_mremap(unsigned long addr,
if (vma->vm_flags & VM_MAYSHARE)
return (unsigned long) -EPERM;
- if (new_len > kobjsize((void *) addr))
+ if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
return (unsigned long) -ENOMEM;
/* all checks complete - do it */
vma->vm_end = vma->vm_start + new_len;
-
- askedalloc -= old_len;
- askedalloc += new_len;
-
return vma->vm_start;
}
EXPORT_SYMBOL(do_mremap);
-asmlinkage unsigned long sys_mremap(unsigned long addr,
- unsigned long old_len, unsigned long new_len,
- unsigned long flags, unsigned long new_addr)
+asmlinkage
+unsigned long sys_mremap(unsigned long addr,
+ unsigned long old_len, unsigned long new_len,
+ unsigned long flags, unsigned long new_addr)
{
unsigned long ret;