VM: add "vm_mmap()" helper function

This continues the theme started with vm_brk() and vm_munmap():
vm_mmap() does the same thing as do_mmap(), but additionally does the
required VM locking.

This uninlines (and rewrites it to be clearer) do_mmap(), which sadly
duplicates it in mm/mmap.c and mm/nommu.c.  But that way we don't have
to export our internal do_mmap_pgoff() function.

Some day we hopefully don't have to export do_mmap() either, if all
modular users can become the simpler vm_mmap() instead.  We're actually
very close to that already, with the notable exception of the (broken)
use in i810, and a couple of stragglers in binfmt_elf.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

15 files changed, 87 insertions, 97 deletions

diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c
index 9efbc1391b3c..89529c9f0605 100644
--- a/arch/tile/kernel/single_step.c
+++ b/arch/tile/kernel/single_step.c
@@ -346,12 +346,10 @@ void single_step_once(struct pt_regs *regs)
                 }
 
                 /* allocate a cache line of writable, executable memory */
-                down_write(&current->mm->mmap_sem);
-                buffer = (void __user *) do_mmap(NULL, 0, 64,
+                buffer = (void __user *) vm_mmap(NULL, 0, 64,
                                           PROT_EXEC | PROT_READ | PROT_WRITE,
                                           MAP_PRIVATE | MAP_ANONYMOUS,
                                           0);
-                up_write(&current->mm->mmap_sem);
 
                 if (IS_ERR((void __force *)buffer)) {
                         kfree(state);
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index b6817ee9033f..4824fb45560f 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -379,26 +379,22 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
                         goto beyond_if;
                 }
 
-                down_write(&current->mm->mmap_sem);
-                error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
+                error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
                                 PROT_READ | PROT_EXEC,
                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
                                 MAP_EXECUTABLE | MAP_32BIT,
                                 fd_offset);
-                up_write(&current->mm->mmap_sem);
 
                 if (error != N_TXTADDR(ex)) {
                         send_sig(SIGKILL, current, 0);
                         return error;
                 }
 
-                down_write(&current->mm->mmap_sem);
-                error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
+                error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
                                 PROT_READ | PROT_WRITE | PROT_EXEC,
                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
                                 MAP_EXECUTABLE | MAP_32BIT,
                                 fd_offset + ex.a_text);
-                up_write(&current->mm->mmap_sem);
                 if (error != N_DATADDR(ex)) {
                         send_sig(SIGKILL, current, 0);
                         return error;
@@ -482,12 +478,10 @@ static int load_aout_library(struct file *file)
                 goto out;
         }
         /* Now use mmap to map the library into memory. */
-        down_write(&current->mm->mmap_sem);
-        error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
+        error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
                         PROT_READ | PROT_WRITE | PROT_EXEC,
                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
                         N_TXTOFF(ex));
-        up_write(&current->mm->mmap_sem);
         retval = error;
         if (error != start_addr)
                 goto out;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8beb9ce79364..1457be305fb1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6336,13 +6336,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                 if (npages && !old.rmap) {
                         unsigned long userspace_addr;
 
-                        down_write(&current->mm->mmap_sem);
-                        userspace_addr = do_mmap(NULL, 0,
+                        userspace_addr = vm_mmap(NULL, 0,
                                                  npages * PAGE_SIZE,
                                                  PROT_READ | PROT_WRITE,
                                                  map_flags,
                                                  0);
-                        up_write(&current->mm->mmap_sem);
 
                         if (IS_ERR((void *)userspace_addr))
                                 return PTR_ERR((void *)userspace_addr);
diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 30372f7b2d45..348b367debeb 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -1510,8 +1510,8 @@ int drm_freebufs(struct drm_device *dev, void *data,
  * \param arg pointer to a drm_buf_map structure.
  * \return zero on success or a negative number on failure.
  *
- * Maps the AGP, SG or PCI buffer region with do_mmap(), and copies information
- * about each buffer into user space. For PCI buffers, it calls do_mmap() with
+ * Maps the AGP, SG or PCI buffer region with vm_mmap(), and copies information
+ * about each buffer into user space. For PCI buffers, it calls vm_mmap() with
  * offset equal to 0, which drm_mmap() interpretes as PCI buffers and calls
  * drm_mmap_dma().
  */
@@ -1553,18 +1553,14 @@ int drm_mapbufs(struct drm_device *dev, void *data,
                                 retcode = -EINVAL;
                                 goto done;
                         }
-                        down_write(&current->mm->mmap_sem);
-                        virtual = do_mmap(file_priv->filp, 0, map->size,
+                        virtual = vm_mmap(file_priv->filp, 0, map->size,
                                           PROT_READ | PROT_WRITE,
                                           MAP_SHARED,
                                           token);
-                        up_write(&current->mm->mmap_sem);
                 } else {
-                        down_write(&current->mm->mmap_sem);
-                        virtual = do_mmap(file_priv->filp, 0, dma->byte_count,
+                        virtual = vm_mmap(file_priv->filp, 0, dma->byte_count,
                                           PROT_READ | PROT_WRITE,
                                           MAP_SHARED, 0);
-                        up_write(&current->mm->mmap_sem);
                 }
                 if (virtual > -1024UL) {
                         /* Real error */
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 26d51979116b..392ce71ed6a1 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -581,10 +581,8 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
         obj->filp->f_op = &exynos_drm_gem_fops;
         obj->filp->private_data = obj;
 
-        down_write(&current->mm->mmap_sem);
-        addr = do_mmap(obj->filp, 0, args->size,
+        addr = vm_mmap(obj->filp, 0, args->size,
                         PROT_READ | PROT_WRITE, MAP_SHARED, 0);
-        up_write(&current->mm->mmap_sem);
 
         drm_gem_object_unreference_unlocked(obj);
 
diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index b85337f06fbf..a4ba453b3d27 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -129,6 +129,7 @@ static int i810_map_buffer(struct drm_buf *buf, struct drm_file *file_priv)
         if (buf_priv->currently_mapped == I810_BUF_MAPPED)
                 return -EINVAL;
 
+        /* This is all entirely broken */
         down_write(&current->mm->mmap_sem);
         old_fops = file_priv->filp->f_op;
         file_priv->filp->f_op = &i810_buffer_fops;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 0e3c6acde955..0d1e4b7b4b99 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1087,11 +1087,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
         if (obj == NULL)
                 return -ENOENT;
 
-        down_write(&current->mm->mmap_sem);
-        addr = do_mmap(obj->filp, 0, args->size,
+        addr = vm_mmap(obj->filp, 0, args->size,
                        PROT_READ | PROT_WRITE, MAP_SHARED,
                        args->offset);
-        up_write(&current->mm->mmap_sem);
         drm_gem_object_unreference_unlocked(obj);
         if (IS_ERR((void *)addr))
                 return addr;
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index 88527492b917..d146e181d10d 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -319,24 +319,20 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
                         goto beyond_if;
                 }
 
-                down_write(&current->mm->mmap_sem);
-                error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
+                error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
                         PROT_READ | PROT_EXEC,
                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
                         fd_offset);
-                up_write(&current->mm->mmap_sem);
 
                 if (error != N_TXTADDR(ex)) {
                         send_sig(SIGKILL, current, 0);
                         return error;
                 }
 
-                down_write(&current->mm->mmap_sem);
-                error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
+                error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
                                 PROT_READ | PROT_WRITE | PROT_EXEC,
                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
                                 fd_offset + ex.a_text);
-                up_write(&current->mm->mmap_sem);
                 if (error != N_DATADDR(ex)) {
                         send_sig(SIGKILL, current, 0);
                         return error;
@@ -417,12 +413,10 @@ static int load_aout_library(struct file *file)
                 goto out;
         }
         /* Now use mmap to map the library into memory. */
-        down_write(&current->mm->mmap_sem);
-        error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
+        error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
                         PROT_READ | PROT_WRITE | PROT_EXEC,
                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
                         N_TXTOFF(ex));
-        up_write(&current->mm->mmap_sem);
         retval = error;
         if (error != start_addr)
                 goto out;
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0708a0bf0ba9..16f735417072 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -958,10 +958,8 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
                    and some applications "depend" upon this behavior.
                    Since we do not have the power to recompile these, we
                    emulate the SVr4 behavior. Sigh. */
-                down_write(&current->mm->mmap_sem);
-                error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
+                error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
                                 MAP_FIXED | MAP_PRIVATE, 0);
-                up_write(&current->mm->mmap_sem);
         }
 
 #ifdef ELF_PLAT_INIT
@@ -1046,8 +1044,7 @@ static int load_elf_library(struct file *file)
                 eppnt++;
 
         /* Now use mmap to map the library into memory. */
-        down_write(&current->mm->mmap_sem);
-        error = do_mmap(file,
+        error = vm_mmap(file,
                         ELF_PAGESTART(eppnt->p_vaddr),
                         (eppnt->p_filesz +
                          ELF_PAGEOFFSET(eppnt->p_vaddr)),
@@ -1055,7 +1052,6 @@ static int load_elf_library(struct file *file)
                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
                         (eppnt->p_offset -
                          ELF_PAGEOFFSET(eppnt->p_vaddr)));
-        up_write(&current->mm->mmap_sem);
         if (error != ELF_PAGESTART(eppnt->p_vaddr))
                 goto out_free_ph;
 
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 9bd5612a8224..d390a0fffc65 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -390,21 +390,17 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
             (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
                 stack_prot |= PROT_EXEC;
 
-        down_write(&current->mm->mmap_sem);
-        current->mm->start_brk = do_mmap(NULL, 0, stack_size, stack_prot,
+        current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
                                          MAP_PRIVATE | MAP_ANONYMOUS |
                                          MAP_UNINITIALIZED | MAP_GROWSDOWN,
                                          0);
 
         if (IS_ERR_VALUE(current->mm->start_brk)) {
-                up_write(&current->mm->mmap_sem);
                 retval = current->mm->start_brk;
                 current->mm->start_brk = 0;
                 goto error_kill;
         }
 
-        up_write(&current->mm->mmap_sem);
-
         current->mm->brk = current->mm->start_brk;
         current->mm->context.end_brk = current->mm->start_brk;
         current->mm->context.end_brk +=
@@ -955,10 +951,8 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
                 mflags |= MAP_EXECUTABLE;
 
-        down_write(&mm->mmap_sem);
-        maddr = do_mmap(NULL, load_addr, top - base,
+        maddr = vm_mmap(NULL, load_addr, top - base,
                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
-        up_write(&mm->mmap_sem);
         if (IS_ERR_VALUE(maddr))
                 return (int) maddr;
 
@@ -1096,10 +1090,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 
                 /* create the mapping */
                 disp = phdr->p_vaddr & ~PAGE_MASK;
-                down_write(&mm->mmap_sem);
-                maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
+                maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
                                 phdr->p_offset - disp);
-                up_write(&mm->mmap_sem);
 
                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
                        loop, phdr->p_memsz + disp, prot, flags,
@@ -1143,10 +1135,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
                         unsigned long xmaddr;
 
                         flags |= MAP_FIXED | MAP_ANONYMOUS;
-                        down_write(&mm->mmap_sem);
-                        xmaddr = do_mmap(NULL, xaddr, excess - excess1,
+                        xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
                                          prot, flags, 0);
-                        up_write(&mm->mmap_sem);
 
                         kdebug("mmap[%d] <anon>"
                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 024d20ee3ca3..6b2daf99fab8 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -542,10 +542,8 @@ static int load_flat_file(struct linux_binprm * bprm,
                  */
                 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 
-                down_write(&current->mm->mmap_sem);
-                textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
+                textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
                                   MAP_PRIVATE|MAP_EXECUTABLE, 0);
-                up_write(&current->mm->mmap_sem);
                 if (!textpos || IS_ERR_VALUE(textpos)) {
                         if (!textpos)
                                 textpos = (unsigned long) -ENOMEM;
@@ -556,10 +554,8 @@ static int load_flat_file(struct linux_binprm * bprm,
 
                 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
                 len = PAGE_ALIGN(len);
-                down_write(&current->mm->mmap_sem);
-                realdatastart = do_mmap(0, 0, len,
+                realdatastart = vm_mmap(0, 0, len,
                         PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
-                up_write(&current->mm->mmap_sem);
 
                 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
                         if (!realdatastart)
@@ -603,10 +599,8 @@ static int load_flat_file(struct linux_binprm * bprm,
 
                 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
                 len = PAGE_ALIGN(len);
-                down_write(&current->mm->mmap_sem);
-                textpos = do_mmap(0, 0, len,
+                textpos = vm_mmap(0, 0, len,
                         PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
-                up_write(&current->mm->mmap_sem);
 
                 if (!textpos || IS_ERR_VALUE(textpos)) {
                         if (!textpos)
diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
index e4fc746629a7..4517aaff61b4 100644
--- a/fs/binfmt_som.c
+++ b/fs/binfmt_som.c
@@ -147,10 +147,8 @@ static int map_som_binary(struct file *file,
         code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
         current->mm->start_code = code_start;
         current->mm->end_code = code_start + code_size;
-        down_write(&current->mm->mmap_sem);
-        retval = do_mmap(file, code_start, code_size, prot,
+        retval = vm_mmap(file, code_start, code_size, prot,
                         flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
-        up_write(&current->mm->mmap_sem);
         if (retval < 0 && retval > -1024)
                 goto out;
 
@@ -158,20 +156,16 @@ static int map_som_binary(struct file *file,
         data_size = SOM_PAGEALIGN(hpuxhdr->exec_dsize);
         current->mm->start_data = data_start;
         current->mm->end_data = bss_start = data_start + data_size;
-        down_write(&current->mm->mmap_sem);
-        retval = do_mmap(file, data_start, data_size,
+        retval = vm_mmap(file, data_start, data_size,
                         prot | PROT_WRITE, flags,
                         SOM_PAGESTART(hpuxhdr->exec_dfile));
-        up_write(&current->mm->mmap_sem);
         if (retval < 0 && retval > -1024)
                 goto out;
 
         som_brk = bss_start + SOM_PAGEALIGN(hpuxhdr->exec_bsize);
         current->mm->start_brk = current->mm->brk = som_brk;
-        down_write(&current->mm->mmap_sem);
-        retval = do_mmap(NULL, bss_start, som_brk - bss_start,
+        retval = vm_mmap(NULL, bss_start, som_brk - bss_start,
                         prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
-        up_write(&current->mm->mmap_sem);
         if (retval > 0 || retval < -1024)
                 retval = 0;
 out:
diff --git a/include/linux/mm.h b/include/linux/mm.h
index cb61950a3aa1..86a692c3b238 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1393,31 +1393,20 @@ extern int install_special_mapping(struct mm_struct *mm,
 
 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
-        unsigned long len, unsigned long prot,
-        unsigned long flag, unsigned long pgoff);
 extern unsigned long mmap_region(struct file *file, unsigned long addr,
         unsigned long len, unsigned long flags,
         vm_flags_t vm_flags, unsigned long pgoff);
-
-static inline unsigned long do_mmap(struct file *file, unsigned long addr,
-        unsigned long len, unsigned long prot,
-        unsigned long flag, unsigned long offset)
-{
-        unsigned long ret = -EINVAL;
-        if ((offset + PAGE_ALIGN(len)) < offset)
-                goto out;
-        if (!(offset & ~PAGE_MASK))
-                ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
-out:
-        return ret;
-}
-
+extern unsigned long do_mmap(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
 
 /* These take the mm semaphore themselves */
 extern unsigned long vm_brk(unsigned long, unsigned long);
 extern int vm_munmap(struct mm_struct *, unsigned long, size_t);
+extern unsigned long vm_mmap(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
 
 /* truncate.c */
 extern void truncate_inode_pages(struct address_space *, loff_t);
diff --git a/mm/mmap.c b/mm/mmap.c
index 4af45f519f19..b38b47ef1f77 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -953,7 +953,7 @@ static inline unsigned long round_hint_to_min(unsigned long hint)
  * The caller must hold down_write(&current->mm->mmap_sem).
  */
 
-unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+static unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
                         unsigned long len, unsigned long prot,
                         unsigned long flags, unsigned long pgoff)
 {
@@ -1089,7 +1089,32 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 
         return mmap_region(file, addr, len, flags, vm_flags, pgoff);
 }
-EXPORT_SYMBOL(do_mmap_pgoff);
+
+unsigned long do_mmap(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot,
+        unsigned long flag, unsigned long offset)
+{
+        if (unlikely(offset + PAGE_ALIGN(len) < offset))
+                return -EINVAL;
+        if (unlikely(offset & ~PAGE_MASK))
+                return -EINVAL;
+        return do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(do_mmap);
+
+unsigned long vm_mmap(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot,
+        unsigned long flag, unsigned long offset)
+{
+        unsigned long ret;
+        struct mm_struct *mm = current->mm;
+
+        down_write(&mm->mmap_sem);
+        ret = do_mmap(file, addr, len, prot, flag, offset);
+        up_write(&mm->mmap_sem);
+        return ret;
+}
+EXPORT_SYMBOL(vm_mmap);
 
 SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
                 unsigned long, prot, unsigned long, flags,
diff --git a/mm/nommu.c b/mm/nommu.c
index 11a69b22bd4b..dd00383be2d9 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1233,7 +1233,7 @@ enomem:
 /*
  * handle mapping creation for uClinux
  */
-unsigned long do_mmap_pgoff(struct file *file,
+static unsigned long do_mmap_pgoff(struct file *file,
                             unsigned long addr,
                             unsigned long len,
                             unsigned long prot,
@@ -1470,7 +1470,32 @@ error_getting_region:
         show_free_areas(0);
         return -ENOMEM;
 }
-EXPORT_SYMBOL(do_mmap_pgoff);
+
+unsigned long do_mmap(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot,
+        unsigned long flag, unsigned long offset)
+{
+        if (unlikely(offset + PAGE_ALIGN(len) < offset))
+                return -EINVAL;
+        if (unlikely(offset & ~PAGE_MASK))
+                return -EINVAL;
+        return do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(do_mmap);
+
+unsigned long vm_mmap(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot,
+        unsigned long flag, unsigned long offset)
+{
+        unsigned long ret;
+        struct mm_struct *mm = current->mm;
+
+        down_write(&mm->mmap_sem);
+        ret = do_mmap(file, addr, len, prot, flag, offset);
+        up_write(&mm->mmap_sem);
+        return ret;
+}
+EXPORT_SYMBOL(vm_mmap);
 
 SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
                 unsigned long, prot, unsigned long, flags,