[PATCH] NOMMU: Separate out VMAs

David Howells
2007-08-03T14:03:50Z

Here's a preview of my patch to give each process a separate list of VMAs
under NOMMU mode, just as under MMU mode. Could you have a look over it
please?

Could you also see if you get a memory leak on the blackfin CPU? I see a leak
when I use this patch, but I'm not sure whether it's this patch, or whether
it's something else in the arch that is suppressed without this patch.

As far as I can tell by page counting there shouldn't be a leak.

I've taken some of Bernd's patch into this one, and I'll take a bit more when
I've done.

David

[PATCH] NOMMU: Make VMAs per MM as for MMU-mode linux

From: David Howells <dhowells@redhat.com>

Make VMAs per mm_struct as for MMU-mode linux. This solves the nattch problem
for SYSV SHM where nattch for a segment does not reflect the number of shmat's
(and forks) done.

Signed-Off-By: David Howells <dhowells@redhat.com>
---

arch/frv/Makefile | 2
arch/frv/kernel/ptrace.c | 11 -
fs/binfmt_elf_fdpic.c | 29 --
fs/proc/internal.h | 2
fs/proc/nommu.c | 71 ++--
fs/proc/task_nommu.c | 135 +++++--
include/asm-frv/mmu.h | 1
include/linux/mm.h | 43 +-
ipc/shm.c | 12 +
mm/nommu.c | 852 +++++++++++++++++++++++++++++++---------------
10 files changed, 740 insertions(+), 418 deletions(-)

diff --git a/arch/frv/Makefile b/arch/frv/Makefile
index 9bf7345..038e3a8 100644
--- a/arch/frv/Makefile
+++ b/arch/frv/Makefile
@@ -88,7 +88,7 @@ ASFLAGS += -mno-fdpic
# make sure the .S files get compiled with debug info
# and disable optimisations that are unhelpful whilst debugging
ifdef CONFIG_DEBUG_INFO
-#CFLAGS += -O1
+CFLAGS += -O1
AFLAGS += -Wa,--gdwarf2
ASFLAGS += -Wa,--gdwarf2
endif
diff --git a/arch/frv/kernel/ptrace.c b/arch/frv/kernel/ptrace.c
index 709e9bd..e9af8de 100644
--- a/arch/frv/kernel/ptrace.c
+++ b/arch/frv/kernel/ptrace.c
@@ -69,7 +69,8 @@ static inline int put_reg(struct task_struct *task, int regno,
}

/*
- * check that an address falls within the bounds of the target process's memory mappings
+ * check that an address falls within the bounds of the target process's memory
+ * mappings
*/
static inline int is_user_addr_valid(struct task_struct *child,
unsigned long start, unsigned long len)
@@ -79,11 +80,11 @@ static inline int is_user_addr_valid(struct task_struct *child,
return -EIO;
return 0;
#else
- struct vm_list_struct *vml;
+ struct vm_area_struct *vma;

- for (vml = child->mm->context.vmlist; vml; vml = vml->next)
- if (start >= vml->vma->vm_start && start + len <= vml->vma->vm_end)
- return 0;
+ vma = find_vma(child->mm, start);
+ if (start >= vma->vm_start && start + len <= vma->vm_end)
+ return 0;

return -EIO;
#endif
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 2f5d8db..c76070f 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -384,7 +384,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
}

/* expand the stack mapping to use up the entire allocation granule */
- fullsize = ksize((char *) current->mm->start_brk);
+ fullsize = PAGE_ALIGN(current->mm->start_brk);
if (!IS_ERR_VALUE(do_mremap(current->mm->start_brk, stack_size,
fullsize, 0, 0)))
stack_size = fullsize;
@@ -1524,11 +1524,9 @@ end_coredump:
static int elf_fdpic_dump_segments(struct file *file, size_t *size,
unsigned long *limit, unsigned long mm_flags)
{
- struct vm_list_struct *vml;
-
- for (vml = current->mm->context.vmlist; vml; vml = vml->next) {
- struct vm_area_struct *vma = vml->vma;
+ struct vm_area_struct *vma;

+ for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
if (!maydump(vma, mm_flags))
continue;

@@ -1576,9 +1574,6 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
elf_fpxregset_t *xfpu = NULL;
#endif
int thread_status_size = 0;
-#ifndef CONFIG_MMU
- struct vm_list_struct *vml;
-#endif
elf_addr_t *auxv;
unsigned long mm_flags;

@@ -1645,13 +1640,7 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
fill_prstatus(prstatus, current, signr);
elf_core_copy_regs(&prstatus->pr_reg, regs);

-#ifdef CONFIG_MMU
segs = current->mm->map_count;
-#else
- segs = 0;
- for (vml = current->mm->context.vmlist; vml; vml = vml->next)
- segs++;
-#endif
#ifdef ELF_CORE_EXTRA_PHDRS
segs += ELF_CORE_EXTRA_PHDRS;
#endif
@@ -1726,20 +1715,10 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
mm_flags = current->mm->flags;

/* write program headers for segments dump */
- for (
-#ifdef CONFIG_MMU
- vma = current->mm->mmap; vma; vma = vma->vm_next
-#else
- vml = current->mm->context.vmlist; vml; vml = vml->next
-#endif
- ) {
+ for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
struct elf_phdr phdr;
size_t sz;

-#ifndef CONFIG_MMU
- vma = vml->vma;
-#endif
-
sz = vma->vm_end - vma->vm_start;

phdr.p_type = PT_LOAD;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index b215c35..e8aa8d3 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -33,8 +33,6 @@ do { \
(vmi)->used = 0; \
(vmi)->largest_chunk = 0; \
} while(0)
-
-extern int nommu_vma_show(struct seq_file *, struct vm_area_struct *);
#endif

extern int maps_protect;
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
index 22f789d..c3b6b24 100644
--- a/fs/proc/nommu.c
+++ b/fs/proc/nommu.c
@@ -33,33 +33,33 @@
#include "internal.h"

/*
- * display a single VMA to a sequenced file
+ * display a single region to a sequenced file
*/
-int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
+static int nommu_region_show(struct seq_file *m, struct vm_region *region)
{
unsigned long ino = 0;
struct file *file;
dev_t dev = 0;
int flags, len;

- flags = vma->vm_flags;
- file = vma->vm_file;
+ flags = region->vm_flags;
+ file = region->vm_file;

if (file) {
- struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ struct inode *inode = region->vm_file->f_path.dentry->d_inode;
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
}

seq_printf(m,
"%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
- vma->vm_start,
- vma->vm_end,
+ region->vm_start,
+ region->vm_end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
- vma->vm_pgoff << PAGE_SHIFT,
+ region->vm_pgoff << PAGE_SHIFT,
MAJOR(dev), MINOR(dev), ino, &len);

if (file) {
@@ -75,61 +75,54 @@ int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
}

/*
- * display a list of all the VMAs the kernel knows about
+ * display a list of all the REGIONs the kernel knows about
* - nommu kernals have a single flat list
*/
-static int nommu_vma_list_show(struct seq_file *m, void *v)
+static int nommu_region_list_show(struct seq_file *m, void *_p)
{
- struct vm_area_struct *vma;
+ struct rb_node *p = _p;

- vma = rb_entry((struct rb_node *) v, struct vm_area_struct, vm_rb);
- return nommu_vma_show(m, vma);
+ return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
}

-static void *nommu_vma_list_start(struct seq_file *m, loff_t *_pos)
+static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
{
- struct rb_node *_rb;
+ struct rb_node *p;
loff_t pos = *_pos;
- void *next = NULL;

- down_read(&nommu_vma_sem);
+ down_read(&nommu_region_sem);

- for (_rb = rb_first(&nommu_vma_tree); _rb; _rb = rb_next(_rb)) {
- if (pos == 0) {
- next = _rb;
- break;
- }
- pos--;
- }
-
- return next;
+ for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
+ if (pos-- == 0)
+ return p;
+ return NULL;
}

-static void nommu_vma_list_stop(struct seq_file *m, void *v)
+static void nommu_region_list_stop(struct seq_file *m, void *v)
{
- up_read(&nommu_vma_sem);
+ up_read(&nommu_region_sem);
}

-static void *nommu_vma_list_next(struct seq_file *m, void *v, loff_t *pos)
+static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
{
(*pos)++;
return rb_next((struct rb_node *) v);
}

-static struct seq_operations proc_nommu_vma_list_seqop = {
- .start = nommu_vma_list_start,
- .next = nommu_vma_list_next,
- .stop = nommu_vma_list_stop,
- .show = nommu_vma_list_show
+static struct seq_operations proc_nommu_region_list_seqop = {
+ .start = nommu_region_list_start,
+ .next = nommu_region_list_next,
+ .stop = nommu_region_list_stop,
+ .show = nommu_region_list_show
};

-static int proc_nommu_vma_list_open(struct inode *inode, struct file *file)
+static int proc_nommu_region_list_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &proc_nommu_vma_list_seqop);
+ return seq_open(file, &proc_nommu_region_list_seqop);
}

-static const struct file_operations proc_nommu_vma_list_operations = {
- .open = proc_nommu_vma_list_open,
+static const struct file_operations proc_nommu_region_list_operations = {
+ .open = proc_nommu_region_list_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
@@ -137,7 +130,7 @@ static const struct file_operations proc_nommu_vma_list_operations = {

static int __init proc_nommu_init(void)
{
- create_seq_entry("maps", S_IRUGO, &proc_nommu_vma_list_operations);
+ create_seq_entry("maps", S_IRUGO, &proc_nommu_region_list_operations);
return 0;
}

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index d8b8c71..5a79c5a 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -14,25 +14,25 @@
*/
char *task_mem(struct mm_struct *mm, char *buffer)
{
- struct vm_list_struct *vml;
+ struct vm_area_struct *vma;
+ struct rb_node *p;
unsigned long bytes = 0, sbytes = 0, slack = 0;

down_read(&mm->mmap_sem);
- for (vml = mm->context.vmlist; vml; vml = vml->next) {
- if (!vml->vma)
- continue;
+ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
+ vma = rb_entry(p, struct vm_area_struct, vm_rb);

- bytes += kobjsize(vml);
+ bytes += kobjsize(vma);
if (atomic_read(&mm->mm_count) > 1 ||
- atomic_read(&vml->vma->vm_usage) > 1
- ) {
- sbytes += kobjsize((void *) vml->vma->vm_start);
- sbytes += kobjsize(vml->vma);
+ vma->vm_region ||
+ vma->vm_flags & VM_MAYSHARE) {
+ sbytes += kobjsize((void *) vma->vm_start);
+ if (vma->vm_region)
+ sbytes += kobjsize(vma->vm_region);
} else {
- bytes += kobjsize((void *) vml->vma->vm_start);
- bytes += kobjsize(vml->vma);
- slack += kobjsize((void *) vml->vma->vm_start) -
- (vml->vma->vm_end - vml->vma->vm_start);
+ bytes += kobjsize((void *) vma->vm_start);
+ slack += kobjsize((void *) vma->vm_start) -
+ (vma->vm_end - vma->vm_start);
}
}

@@ -70,13 +70,14 @@ char *task_mem(struct mm_struct *mm, char *buffer)

unsigned long task_vsize(struct mm_struct *mm)
{
- struct vm_list_struct *tbp;
+ struct vm_area_struct *vma;
+ struct rb_node *p;
unsigned long vsize = 0;

down_read(&mm->mmap_sem);
- for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
- if (tbp->vma)
- vsize += kobjsize((void *) tbp->vma->vm_start);
+ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
+ vma = rb_entry(p, struct vm_area_struct, vm_rb);
+ vsize += vma->vm_region->vm_end - vma->vm_region->vm_start;
}
up_read(&mm->mmap_sem);
return vsize;
@@ -85,16 +86,15 @@ unsigned long task_vsize(struct mm_struct *mm)
int task_statm(struct mm_struct *mm, int *shared, int *text,
int *data, int *resident)
{
- struct vm_list_struct *tbp;
+ struct vm_area_struct *vma;
+ struct rb_node *p;
int size = kobjsize(mm);

down_read(&mm->mmap_sem);
- for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
- size += kobjsize(tbp);
- if (tbp->vma) {
- size += kobjsize(tbp->vma);
- size += kobjsize((void *) tbp->vma->vm_start);
- }
+ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
+ vma = rb_entry(p, struct vm_area_struct, vm_rb);
+ size += kobjsize(vma);
+ size += kobjsize((void *) vma->vm_start);
}

size += (*text = mm->end_code - mm->start_code);
@@ -106,32 +106,24 @@ int task_statm(struct mm_struct *mm, int *shared, int *text,

int proc_exe_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
- struct vm_list_struct *vml;
struct vm_area_struct *vma;
struct task_struct *task = get_proc_task(inode);
struct mm_struct *mm = get_task_mm(task);
+ struct rb_node *p;
int result = -ENOENT;

if (!mm)
goto out;
- down_read(&mm->mmap_sem);

- vml = mm->context.vmlist;
- vma = NULL;
- while (vml) {
- if ((vml->vma->vm_flags & VM_EXECUTABLE) && vml->vma->vm_file) {
- vma = vml->vma;
- break;
+ down_read(&mm->mmap_sem);
+ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
+ vma = rb_entry(p, struct vm_area_struct, vm_rb);
+ if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
+ *mnt = mntget(vma->vm_file->f_path.mnt);
+ *dentry = dget(vma->vm_file->f_path.dentry);
+ result = 0;
}
- vml = vml->next;
- }
-
- if (vma) {
- *mnt = mntget(vma->vm_file->f_path.mnt);
- *dentry = dget(vma->vm_file->f_path.dentry);
- result = 0;
}
-
up_read(&mm->mmap_sem);
mmput(mm);
out:
@@ -139,25 +131,66 @@ out:
}

/*
+ * display a single VMA to a sequenced file
+ */
+static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
+{
+ unsigned long ino = 0;
+ struct file *file;
+ dev_t dev = 0;
+ int flags, len;
+
+ flags = vma->vm_flags;
+ file = vma->vm_file;
+
+ if (file) {
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ dev = inode->i_sb->s_dev;
+ ino = inode->i_ino;
+ }
+
+ seq_printf(m,
+ "%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
+ vma->vm_start,
+ vma->vm_end,
+ flags & VM_READ ? 'r' : '-',
+ flags & VM_WRITE ? 'w' : '-',
+ flags & VM_EXEC ? 'x' : '-',
+ flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
+ vma->vm_pgoff << PAGE_SHIFT,
+ MAJOR(dev), MINOR(dev), ino, &len);
+
+ if (file) {
+ len = 25 + sizeof(void *) * 6 - len;
+ if (len < 1)
+ len = 1;
+ seq_printf(m, "%*c", len, ' ');
+ seq_path(m, file->f_path.mnt, file->f_path.dentry, "");
+ }
+
+ seq_putc(m, '\n');
+ return 0;
+}
+
+/*
* display mapping lines for a particular process's /proc/pid/maps
*/
-static int show_map(struct seq_file *m, void *_vml)
+static int show_map(struct seq_file *m, void *_p)
{
- struct vm_list_struct *vml = _vml;
struct proc_maps_private *priv = m->private;
- struct task_struct *task = priv->task;
+ struct rb_node *p = _p;

- if (maps_protect && !ptrace_may_attach(task))
+ if (maps_protect && !ptrace_may_attach(priv->task))
return -EACCES;

- return nommu_vma_show(m, vml->vma);
+ return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb));
}

static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
- struct vm_list_struct *vml;
struct mm_struct *mm;
+ struct rb_node *p;
loff_t n = *pos;

/* pin the task and mm whilst we play with them */
@@ -175,9 +208,9 @@ static void *m_start(struct seq_file *m, loff_t *pos)
down_read(&mm->mmap_sem);

/* start from the Nth VMA */
- for (vml = mm->context.vmlist; vml; vml = vml->next)
+ for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
if (n-- == 0)
- return vml;
+ return p;
return NULL;
}

@@ -193,12 +226,12 @@ static void m_stop(struct seq_file *m, void *_vml)
}
}

-static void *m_next(struct seq_file *m, void *_vml, loff_t *pos)
+static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
{
- struct vm_list_struct *vml = _vml;
+ struct rb_node *p = _p;

(*pos)++;
- return vml ? vml->next : NULL;
+ return p ? rb_next(p) : NULL;
}

static struct seq_operations proc_pid_maps_ops = {
diff --git a/include/asm-frv/mmu.h b/include/asm-frv/mmu.h
index 22c0371..86ca0e8 100644
--- a/include/asm-frv/mmu.h
+++ b/include/asm-frv/mmu.h
@@ -22,7 +22,6 @@ typedef struct {
unsigned long dtlb_ptd_mapping; /* [DAMR5] PTD mapping for dtlb cached PGE */

#else
- struct vm_list_struct *vmlist;
unsigned long end_brk;

#endif
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 655094d..8c18ae8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -50,6 +50,30 @@ extern int sysctl_legacy_va_layout;
* mmap() functions).
*/

+#ifndef CONFIG_MMU
+/*
+ * A region containing a mapping of a non-memory backed file under NOMMU
+ * conditions. These are held in a global tree and are pinned by the VMAs that
+ * map parts of them.
+ */
+struct vm_region {
+ struct rb_node vm_rb; /* link in global region tree */
+ /* the first parameters define the region as for the VMA */
+ unsigned long vm_flags;
+ unsigned long vm_start;
+ unsigned long vm_end;
+ unsigned long vm_pgoff;
+ struct file *vm_file;
+
+ atomic_t vm_usage; /* region usage count */
+};
+
+extern struct rb_root nommu_region_tree;
+extern struct rw_semaphore nommu_region_sem;
+
+extern unsigned int kobjsize(const void *objp);
+#endif
+
/*
* This struct defines a memory VMM memory area. There is one of these
* per VM-area/task. A VM area is any part of the process virtual memory
@@ -106,7 +130,7 @@ struct vm_area_struct {
unsigned long vm_truncate_count;/* truncate_count or restart_addr */

#ifndef CONFIG_MMU
- atomic_t vm_usage; /* refcount (VMAs shared if !MMU) */
+ struct vm_region *vm_region; /* NOMMU mapping region */
#endif
#ifdef CONFIG_NUMA
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
@@ -116,23 +140,6 @@ struct vm_area_struct {
extern struct kmem_cache *vm_area_cachep;

/*
- * This struct defines the per-mm list of VMAs for uClinux. If CONFIG_MMU is
- * disabled, then there's a single shared list of VMAs maintained by the
- * system, and mm's subscribe to these individually
- */
-struct vm_list_struct {
- struct vm_list_struct *next;
- struct vm_area_struct *vma;
-};
-
-#ifndef CONFIG_MMU
-extern struct rb_root nommu_vma_tree;
-extern struct rw_semaphore nommu_vma_sem;
-
-extern unsigned int kobjsize(const void *objp);
-#endif
-
-/*
* vm_flags..
*/
#define VM_READ 0x00000001 /* currently active flags */
diff --git a/ipc/shm.c b/ipc/shm.c
index a86a3a5..d0f1bf8 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1033,6 +1033,7 @@ asmlinkage long sys_shmdt(char __user *shmaddr)
*/
vma = find_vma(mm, addr);

+#ifdef CONFIG_MMU
while (vma) {
next = vma->vm_next;

@@ -1077,6 +1078,17 @@ asmlinkage long sys_shmdt(char __user *shmaddr)
vma = next;
}

+#else /* CONFIG_MMU */
+ /* under NOMMU conditions, the exact address to be destroyed must be
+ * given */
+ retval = -EINVAL;
+ if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
+ do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
+ retval = 0;
+ }
+
+#endif
+
up_write(&mm->mmap_sem);
return retval;
}
diff --git a/mm/nommu.c b/mm/nommu.c
index 9eef6a3..01253f6 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -6,7 +6,7 @@
*
* See Documentation/nommu-mmap.txt
*
- * Copyright (c) 2004-2005 David Howells <dhowells@redhat.com>
+ * Copyright (c) 2004-2007 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>
@@ -32,11 +32,23 @@
#include <asm/tlb.h>
#include <asm/tlbflush.h>

+#if 1
+#define kenter(FMT, ...) printk("==> %s("FMT")\n",__FUNCTION__ ,##__VA_ARGS__)
+#define kleave(FMT, ...) printk("<== %s()"FMT"\n",__FUNCTION__ ,##__VA_ARGS__)
+#define kdebug(FMT, ...) printk(FMT"\n" ,##__VA_ARGS__)
+#else
+#define kenter(FMT, ...) do {} while(0)
+#define kleave(FMT, ...) do {} while(0)
+#define kdebug(FMT, ...) do {} while(0)
+#endif
+#define _enter(FMT, ...) do {} while(0)
+#define _leave(FMT, ...) do {} while(0)
+#define _debug(FMT, ...) do {} while(0)
+
void *high_memory;
struct page *mem_map;
unsigned long max_mapnr;
unsigned long num_physpages;
-unsigned long askedalloc, realalloc;
atomic_t vm_committed_space = ATOMIC_INIT(0);
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
@@ -47,13 +59,17 @@ EXPORT_SYMBOL(mem_map);
EXPORT_SYMBOL(__vm_enough_memory);
EXPORT_SYMBOL(num_physpages);

-/* list of shareable VMAs */
-struct rb_root nommu_vma_tree = RB_ROOT;
-DECLARE_RWSEM(nommu_vma_sem);
+/* list of shareable regions */
+struct rb_root nommu_region_tree = RB_ROOT;
+DECLARE_RWSEM(nommu_region_sem);

struct vm_operations_struct generic_file_vm_ops = {
};

+static atomic_t pages_allocated;
+
+#define static static noinline
+
/*
* Handle all mappings that got truncated by a "truncate()"
* system call.
@@ -113,7 +129,7 @@ unsigned int kobjsize(const void *objp)
BUG_ON(page->index < 0);
BUG_ON(page->index >= MAX_ORDER);

- return (PAGE_SIZE << page->index);
+ return PAGE_SIZE << page->index;
}

/*
@@ -341,16 +357,104 @@ static void show_process_blocks(void)
* 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
*/
-static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
+static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
- struct vm_list_struct **ppv;
+ struct vm_area_struct *pvma, **pp;
+ struct address_space *mapping;
+ struct rb_node **p, *parent;
+
+ _enter(",%p", vma);
+
+ BUG_ON(!vma->vm_region);
+
+ mm->map_count++;
+ vma->vm_mm = mm;
+
+ /* add the VMA to the mapping */
+ if (vma->vm_file) {
+ mapping = vma->vm_file->f_mapping;
+
+ flush_dcache_mmap_lock(mapping);
+ vma_prio_tree_insert(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+ }
+
+ /* 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);
+
+ /* 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)
+ p = &(*p)->rb_right;
+ 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();
+ }

- for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
- if ((*ppv)->vma->vm_start > vml->vma->vm_start)
+ rb_link_node(&vma->vm_rb, parent, p);
+ 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;
+ }

- vml->next = *ppv;
- *ppv = vml;
+ vma->vm_next = *pp;
+ *pp = vma;
+}
+
+/*
+ * delete a VMA from an mm_struct
+ */
+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;
+
+ _enter("%p", vma);
+
+ mm->map_count--;
+ if (mm->mmap_cache == vma)
+ mm->mmap_cache = NULL;
+
+ /* remove the VMA from the mapping */
+ if (vma->vm_file) {
+ mapping = vma->vm_file->f_mapping;
+
+ flush_dcache_mmap_lock(mapping);
+ vma_prio_tree_remove(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+ }
+
+ /* 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;
}

/*
@@ -359,18 +463,25 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
*/
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
{
- struct vm_list_struct *loop, *vml;
+ struct vm_area_struct *vma;
+ struct rb_node *n = mm->mm_rb.rb_node;

- /* 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;
- }
+ /* check the cache first */
+ vma = mm->mmap_cache;
+ if (vma && vma->vm_start <= addr && vma->vm_end > addr)
+ return vma;

- if (vml && vml->vma->vm_end > addr)
- return vml->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;
}
@@ -394,111 +505,161 @@ int expand_stack(struct vm_area_struct *vma, unsigned long address)
* look up the first VMA exactly that exactly matches addr
* - should be called with mm->mmap_sem at least held readlocked
*/
-static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
- unsigned long addr)
+static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
+ unsigned long addr,
+ unsigned long len)
{
- struct vm_list_struct *vml;
+ struct vm_area_struct *vma;
+ struct rb_node *n = mm->mm_rb.rb_node;
+ unsigned long end = addr + len;

- /* 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;
+ /* 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;
}

/*
- * find a VMA in the global tree
+ * check a region tree
*/
-static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
+static noinline bool check_tree_aux(struct rb_node *node,
+ struct rb_node *parent,
+ int depth, char lr)
{
- struct vm_area_struct *vma;
- struct rb_node *n = nommu_vma_tree.rb_node;
+ struct vm_region *region;
+ bool bad = false;
+
+ if (!node)
+ return false;
+
+ if (node->rb_left)
+ bad = check_tree_aux(node->rb_left, node, depth + 2, '/');
+
+ region = rb_entry(node, struct vm_region, vm_rb);
+ _debug("%c %*.*s%c%p {%lx-%lx}",
+ rb_is_red(node) ? 'R' : 'B',
+ depth, depth, "", lr,
+ region, region->vm_start, region->vm_end);
+ if (rb_parent(node) != parent) {
+ printk("BAD: %p != %p\n", rb_parent(node), parent);
+ bad = true;
+ }

- while (n) {
- vma = rb_entry(n, struct vm_area_struct, vm_rb);
+ if (node->rb_right)
+ bad |= check_tree_aux(node->rb_right, node, depth + 2, '\\');

- if (start < vma->vm_start)
- n = n->rb_left;
- else if (start > vma->vm_start)
- n = n->rb_right;
- else
- return vma;
- }
+ return bad;
+}

- return NULL;
+static noinline void check_region_tree(void)
+{
+ if (check_tree_aux(nommu_region_tree.rb_node, NULL, 0, '-'))
+ BUG();
}

/*
- * add a VMA in the global tree
+ * add a region into the global tree
*/
-static void add_nommu_vma(struct vm_area_struct *vma)
+static void add_nommu_region(struct vm_region *region)
{
- struct vm_area_struct *pvma;
- struct address_space *mapping;
- struct rb_node **p = &nommu_vma_tree.rb_node;
- struct rb_node *parent = NULL;
+ struct vm_region *pregion;
+ struct rb_node **p, *parent;

- /* add the VMA to the mapping */
- if (vma->vm_file) {
- mapping = vma->vm_file->f_mapping;
-
- flush_dcache_mmap_lock(mapping);
- vma_prio_tree_insert(vma, &mapping->i_mmap);
- flush_dcache_mmap_unlock(mapping);
- }
-
- /* add the VMA to the master list */
+ parent = NULL;
+ p = &nommu_region_tree.rb_node;
while (*p) {
parent = *p;
- pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
-
- if (vma->vm_start < pvma->vm_start) {
+ pregion = rb_entry(parent, struct vm_region, vm_rb);
+ if (region->vm_start < pregion->vm_start)
p = &(*p)->rb_left;
- }
- else if (vma->vm_start > pvma->vm_start) {
+ else if (region->vm_start > pregion->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 (pregion == region)
+ return;
+ else
+ BUG();
}

- rb_link_node(&vma->vm_rb, parent, p);
- rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
+ rb_link_node(&region->vm_rb, parent, p);
+ rb_insert_color(&region->vm_rb, &nommu_region_tree);
}

/*
- * delete a VMA from the global list
+ * delete a region from the global tree
*/
-static void delete_nommu_vma(struct vm_area_struct *vma)
+static void delete_nommu_region(struct vm_region *region)
{
- struct address_space *mapping;
+ check_region_tree();
+ BUG_ON(!nommu_region_tree.rb_node);
+ rb_erase(&region->vm_rb, &nommu_region_tree);
+ BUG_ON(!nommu_region_tree.rb_node);
+}

- /* remove the VMA from the mapping */
- if (vma->vm_file) {
- mapping = vma->vm_file->f_mapping;
+/*
+ * free a series of pages
+ */
+static void free_page_series(unsigned long from, unsigned long to)
+{
+ for (; from < to; from += PAGE_SIZE) {
+ _debug("- free %lx", from);
+ atomic_dec(&pages_allocated);
+ put_page(virt_to_page(from));
+ }
+}

- flush_dcache_mmap_lock(mapping);
- vma_prio_tree_remove(vma, &mapping->i_mmap);
- flush_dcache_mmap_unlock(mapping);
+/*
+ * release a reference to a region
+ * - the caller must hold the region semaphore, which this releases
+ */
+static void __put_nommu_region(struct vm_region *region)
+ __releases(nommu_region_sem)
+{
+ _enter("%p{%d}", region, atomic_read(&region->vm_usage));
+
+ BUG_ON(!nommu_region_tree.rb_node);
+
+ if (atomic_dec_and_test(&region->vm_usage)) {
+ 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) {
+ _debug("free series");
+ free_page_series(region->vm_start, region->vm_end);
+ }
+ kfree(region);
+ } else {
+ up_write(&nommu_region_sem);
}
+}

- /* remove from the master list */
- rb_erase(&vma->vm_rb, &nommu_vma_tree);
+/*
+ * release a reference to a region
+ */
+static void put_nommu_region(struct vm_region *region)
+{
+ down_write(&nommu_region_sem);
+ __put_nommu_region(region);
}

/*
@@ -712,9 +873,10 @@ 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;

@@ -732,10 +894,14 @@ 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;
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
@@ -754,23 +920,41 @@ static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
* make a private copy of the data and map that instead */
}

+ len = 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(len);
+ _debug("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;
+ /* we allocated a power-of-2 sized page set, so we need to trim off the
+ * excess */
+ total = 1 << order;
+ atomic_add(total, &pages_allocated);
+
+ point = len >> PAGE_SHIFT;
+ while (point < total) {
+ order = ilog2(total - point);
+ _debug("shave %u/%lu", 1 << order, total - point);
+ atomic_sub(1 << order, &pages_allocated);
+ __free_pages(pages + point, order);
+ point += 1 << order;
+ }

-#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
+ total = len >> PAGE_SHIFT;
+ for (point = 0; point > PAGE_SHIFT; point++)
+ BUG_ON(page_count(&pages[point]) != 1);
+
+ base = page_address(pages);
+ region->vm_start = vma->vm_start = (unsigned long) base;
+ region->vm_end = vma->vm_end = vma->vm_start + len;
+ region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;

if (vma->vm_file) {
/* read the contents of a file into the copy */
@@ -800,7 +984,7 @@ static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
return 0;

error_free:
- kfree(base);
+ free_page_series(region->vm_start, region->vm_end);
vma->vm_start = 0;
return ret;

@@ -821,84 +1005,127 @@ 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_region *region = NULL;
struct rb_node *rb;
- unsigned long capabilities, vm_flags;
- void *result;
+ unsigned long capabilities, vm_flags, result;
int ret;

+ _enter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
+
/* decide whether we should attempt the mapping, and if so what sort of
* mapping */
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
&capabilities);
- if (ret < 0)
+ if (ret < 0) {
+ _leave(" = %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 = kzalloc(sizeof(struct vm_region), GFP_KERNEL);
+ if (!region)
+ goto error_getting_region;
+ atomic_set(&region->vm_usage, 1);
+ region->vm_file = file;
+ region->vm_flags = vm_flags;
+ region->vm_pgoff = pgoff;
+
+ vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+ if (!vma)
+ goto error_getting_vma;

- down_write(&nommu_vma_sem);
+ INIT_LIST_HEAD(&vma->anon_vma_node);
+ vma->vm_file = file;
+ vma->vm_flags = vm_flags;
+ vma->vm_pgoff = pgoff;

- /* if we want to share, we need to check for VMAs created by other
+ if (file) {
+ get_file(file);
+ get_file(file);
+ }
+
+ 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) {
+ _debug("share copy");
+ vma->vm_flags |= VM_MAPPED_COPY;
+ } else {
+ _debug("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);
+ kfree(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
@@ -909,105 +1136,92 @@ 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);
- 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;
+ add_nommu_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;
+ goto error_put_region;

/* okay... we have a mapping; now we have to register it */
- result = (void *) vma->vm_start;
-
- if (vma->vm_flags & VM_MAPPED_COPY) {
- realalloc += kobjsize(result);
- askedalloc += len;
- }
-
- realalloc += kobjsize(vma);
- askedalloc += sizeof(*vma);
+ result = vma->vm_start;

current->mm->total_vm += len >> PAGE_SHIFT;

- add_nommu_vma(vma);
-
- shared:
- realalloc += kobjsize(vml);
- askedalloc += sizeof(*vml);
+share:
+ add_vma_to_mm(current->mm, vma);

- add_vma_to_mm(current->mm, vml);
-
- 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;
+ _leave(" = %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);
- kfree(vma);
+ kmem_cache_free(vm_area_cachep, vma);
}
+ _leave(" = %d [pr]", ret);
return ret;

- sharing_violation:
- up_write(&nommu_vma_sem);
+error_just_free:
+ up_write(&nommu_region_sem);
+error:
+ fput(region->vm_file);
+ kfree(region);
+ fput(vma->vm_file);
+ kmem_cache_free(vm_area_cachep, vma);
+ _leave(" = %d", ret);
+ return ret;
+
+sharing_violation:
+ up_write(&nommu_region_sem);
printk("Attempt to share mismatched mappings\n");
- kfree(vml);
- return -EINVAL;
+ ret = -EINVAL;
+ goto error;

- error_getting_vma:
- up_write(&nommu_vma_sem);
- kfree(vml);
- printk("Allocation of vma for %lu byte allocation from process %d failed\n",
+error_getting_vma:
+ kfree(region);
+ printk("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("Allocation of vm region for %lu byte allocation"
+ " from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
@@ -1015,82 +1229,178 @@ unsigned long do_mmap_pgoff(struct file *file,
EXPORT_SYMBOL(do_mmap_pgoff);

/*
- * handle mapping disposal for uClinux
+ * destroy a VMA record
*/
static void put_vma(struct vm_area_struct *vma)
{
- if (vma) {
- down_write(&nommu_vma_sem);
+ _enter("%p", vma);
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+ if (vma->vm_file)
+ fput(vma->vm_file);
+ put_nommu_region(vma->vm_region);
+ kmem_cache_free(vm_area_cachep, vma);
+}

- if (atomic_dec_and_test(&vma->vm_usage)) {
- delete_nommu_vma(vma);
+/*
+ * split a vma into two pieces at address 'addr', a new vma is allocated either
+ * for the first part or the tail.
+ */
+int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, int new_below)
+{
+ struct vm_area_struct *new;
+ struct vm_region *region;
+ unsigned long npages;

- if (vma->vm_ops && vma->vm_ops->close)
- vma->vm_ops->close(vma);
+ _enter("");

- /* 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 = kmalloc(sizeof(*region), GFP_KERNEL);
+ if (!region)
+ return -ENOMEM;

- if (vma->vm_file)
- fput(vma->vm_file);
- kfree(vma);
- }
+ new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+ if (!new) {
+ kfree(region);
+ return -ENOMEM;
+ }

- up_write(&nommu_vma_sem);
+ /* 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;
+
+ if (new_below) {
+ 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_file) {
+ get_file(new->vm_file);
+ get_file(region->vm_file);
+ }
+
+ 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;
+ }
+ 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 region 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 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
+ _enter("");

- 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(vma->vm_mm, vma);

- printk("munmap of non-mmaped memory by process %d (%s): %p\n",
- current->pid, current->comm, (void *) addr);
- return -EINVAL;
+ /* cut the region down to size */
+ region = vma->vm_region;
+ BUG_ON(atomic_read(&region->vm_usage) != 1);

- found:
- vml = *parent;
+ down_write(&nommu_region_sem);
+ delete_nommu_region(region);
+ if (from > region->vm_start)
+ region->vm_end = from;
+ else
+ region->vm_start = to;
+ add_nommu_region(region);
+ up_write(&nommu_region_sem);

- put_vma(vml->vma);
+ free_page_series(from, to);
+ return 0;
+}

- *parent = vml->next;
- realalloc -= kobjsize(vml);
- askedalloc -= sizeof(*vml);
- kfree(vml);
+/*
+ * release a mapping
+ * - under NOMMU conditions the region 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;

- update_hiwater_vm(mm);
- mm->total_vm -= len >> PAGE_SHIFT;
+ _enter(",%lx,%zx", start, len);

-#ifdef DEBUG
- show_process_blocks();
-#endif
+ /* find the first potentially overlapping VMA */
+ vma = find_vma(mm, start);
+ if (!vma) {
+ _leave(" = -EINVAL [no]");
+ return -EINVAL;
+ }

+ /* we're allowed to split an anonymous VMA but not a file-backed one */
+ if (vma->vm_file) {
+ do {
+ if (start > vma->vm_start) {
+ _leave(" = -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);
+ _leave(" = -EINVAL [split file]");
+ return -EINVAL;
+ } else {
+ /* the region 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) {
+ _leave(" = -EINVAL [superset]");
+ return -EINVAL;
+ }
+ if (start != vma->vm_start && end != vma->vm_end) {
+ ret = split_vma(mm, vma, start, 1);
+ if (ret < 0) {
+ _leave(" = %d [split]", ret);
+ return ret;
+ }
+ }
+ return shrink_vma(vma, start, end);
+ }
+
+erase_whole_vma:
+ delete_vma_from_mm(vma);
+ put_vma(vma);
+ _leave(" = 0");
return 0;
}
EXPORT_SYMBOL(do_munmap);
@@ -1107,32 +1417,26 @@ 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(tmp->vma);
+ _enter("");

- 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);
+ put_vma(vma);
}
+
+ _leave("");
}

unsigned long do_brk(unsigned long addr, unsigned long len)
@@ -1163,7 +1467,7 @@ unsigned long do_mremap(unsigned long addr,
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;

@@ -1173,15 +1477,11 @@ 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);