new helper: vm_mmap_pgoff()

take it to mm/util.c, convert vm_mmap() to use of that one and
take it to mm/util.c as well, convert both sys_mmap_pgoff() to
use of vm_mmap_pgoff()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 36 insertions, 57 deletions

diff --git a/mm/internal.h b/mm/internal.h
index aee4761cf9a9..5307a0227317 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -342,3 +342,7 @@ extern u64 hwpoison_filter_flags_mask;
 extern u64 hwpoison_filter_flags_value;
 extern u64 hwpoison_filter_memcg;
 extern u32 hwpoison_filter_enable;
+
+extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
diff --git a/mm/mmap.c b/mm/mmap.c
index 538c905d6d9b..98ef8a6c2cd8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1102,28 +1102,6 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
         return mmap_region(file, addr, len, flags, vm_flags, pgoff);
 }
 
-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;
-
-        if (unlikely(offset + PAGE_ALIGN(len) < offset))
-                return -EINVAL;
-        if (unlikely(offset & ~PAGE_MASK))
-                return -EINVAL;
-
-        ret = security_mmap_file(file, prot, flag);
-        if (!ret) {
-                down_write(&mm->mmap_sem);
-                ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
-                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,
                 unsigned long, fd, unsigned long, pgoff)
@@ -1155,13 +1133,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-        retval = security_mmap_file(file, prot, flags);
-        if (!retval) {
-                down_write(&current->mm->mmap_sem);
-                retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-                up_write(&current->mm->mmap_sem);
-        }
-
+        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
         if (file)
                 fput(file);
 out:
diff --git a/mm/nommu.c b/mm/nommu.c
index e6123a5b2cc1..c4acfbc09972 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1470,28 +1470,6 @@ error_getting_region:
         return -ENOMEM;
 }
 
-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;
-
-        if (unlikely(offset + PAGE_ALIGN(len) < offset))
-                return -EINVAL;
-        if (unlikely(offset & ~PAGE_MASK))
-                return -EINVAL;
-
-        ret = security_mmap_file(file, prot, flag);
-        if (!ret) {
-                down_write(&mm->mmap_sem);
-                ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
-                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,
                 unsigned long, fd, unsigned long, pgoff)
@@ -1508,12 +1486,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-        ret = security_mmap_file(file, prot, flags);
-        if (!ret) {
-                down_write(&current->mm->mmap_sem);
-                retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-                up_write(&current->mm->mmap_sem);
-        }
+        ret = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
 
         if (file)
                 fput(file);
diff --git a/mm/util.c b/mm/util.c
index ae962b31de88..8c7265afa29f 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -4,6 +4,7 @@
 #include <linux/export.h>
 #include <linux/err.h>
 #include <linux/sched.h>
+#include <linux/security.h>
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -341,6 +342,35 @@ int __attribute__((weak)) get_user_pages_fast(unsigned long start,
 }
 EXPORT_SYMBOL_GPL(get_user_pages_fast);
 
+unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot,
+        unsigned long flag, unsigned long pgoff)
+{
+        unsigned long ret;
+        struct mm_struct *mm = current->mm;
+
+        ret = security_mmap_file(file, prot, flag);
+        if (!ret) {
+                down_write(&mm->mmap_sem);
+                ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff);
+                up_write(&mm->mmap_sem);
+        }
+        return ret;
+}
+
+unsigned long vm_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 vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(vm_mmap);
+
 /* Tracepoints definitions. */
 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);