VM: add "vm_brk()" helper function
Linus Torvalds [Fri, 20 Apr 2012 22:35:40 +0000 (15:35 -0700)]
It does the same thing as "do_brk()", except it handles the VM locking
too.

It turns out that all external callers want that anyway, so we can make
do_brk() static to just mm/mmap.c while at it.

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

arch/x86/ia32/ia32_aout.c
fs/binfmt_aout.c
fs/binfmt_elf.c
include/linux/mm.h
mm/mmap.c
mm/nommu.c

index d511d95..b6817ee 100644 (file)
@@ -119,9 +119,7 @@ static void set_brk(unsigned long start, unsigned long end)
        end = PAGE_ALIGN(end);
        if (end <= start)
                return;
-       down_write(&current->mm->mmap_sem);
-       do_brk(start, end - start);
-       up_write(&current->mm->mmap_sem);
+       vm_brk(start, end - start);
 }
 
 #ifdef CORE_DUMP
@@ -332,9 +330,7 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
                pos = 32;
                map_size = ex.a_text+ex.a_data;
 
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(text_addr & PAGE_MASK, map_size);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(text_addr & PAGE_MASK, map_size);
 
                if (error != (text_addr & PAGE_MASK)) {
                        send_sig(SIGKILL, current, 0);
@@ -373,9 +369,7 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
                if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
                        loff_t pos = fd_offset;
 
-                       down_write(&current->mm->mmap_sem);
-                       do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
-                       up_write(&current->mm->mmap_sem);
+                       vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
                        bprm->file->f_op->read(bprm->file,
                                        (char __user *)N_TXTADDR(ex),
                                        ex.a_text+ex.a_data, &pos);
@@ -476,9 +470,7 @@ static int load_aout_library(struct file *file)
                        error_time = jiffies;
                }
 #endif
-               down_write(&current->mm->mmap_sem);
-               do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
-               up_write(&current->mm->mmap_sem);
+               vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 
                file->f_op->read(file, (char __user *)start_addr,
                        ex.a_text + ex.a_data, &pos);
@@ -503,9 +495,7 @@ static int load_aout_library(struct file *file)
        len = PAGE_ALIGN(ex.a_text + ex.a_data);
        bss = ex.a_text + ex.a_data + ex.a_bss;
        if (bss > len) {
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(start_addr + len, bss - len);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(start_addr + len, bss - len);
                retval = error;
                if (error != start_addr + len)
                        goto out;
index 2eb12f1..8852749 100644 (file)
@@ -50,9 +50,7 @@ static int set_brk(unsigned long start, unsigned long end)
        end = PAGE_ALIGN(end);
        if (end > start) {
                unsigned long addr;
-               down_write(&current->mm->mmap_sem);
-               addr = do_brk(start, end - start);
-               up_write(&current->mm->mmap_sem);
+               addr = vm_brk(start, end - start);
                if (BAD_ADDR(addr))
                        return addr;
        }
@@ -280,9 +278,7 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
                pos = 32;
                map_size = ex.a_text+ex.a_data;
 #endif
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(text_addr & PAGE_MASK, map_size);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(text_addr & PAGE_MASK, map_size);
                if (error != (text_addr & PAGE_MASK)) {
                        send_sig(SIGKILL, current, 0);
                        return error;
@@ -313,9 +309,7 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 
                if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
                        loff_t pos = fd_offset;
-                       down_write(&current->mm->mmap_sem);
-                       do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
-                       up_write(&current->mm->mmap_sem);
+                       vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
                        bprm->file->f_op->read(bprm->file,
                                        (char __user *)N_TXTADDR(ex),
                                        ex.a_text+ex.a_data, &pos);
@@ -412,9 +406,7 @@ static int load_aout_library(struct file *file)
                               "N_TXTOFF is not page aligned. Please convert library: %s\n",
                               file->f_path.dentry->d_name.name);
                }
-               down_write(&current->mm->mmap_sem);
-               do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
-               up_write(&current->mm->mmap_sem);
+               vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
                
                file->f_op->read(file, (char __user *)start_addr,
                        ex.a_text + ex.a_data, &pos);
@@ -438,9 +430,7 @@ static int load_aout_library(struct file *file)
        len = PAGE_ALIGN(ex.a_text + ex.a_data);
        bss = ex.a_text + ex.a_data + ex.a_bss;
        if (bss > len) {
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(start_addr + len, bss - len);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(start_addr + len, bss - len);
                retval = error;
                if (error != start_addr + len)
                        goto out;
index 48ffb3d..0708a0b 100644 (file)
@@ -82,9 +82,7 @@ static int set_brk(unsigned long start, unsigned long end)
        end = ELF_PAGEALIGN(end);
        if (end > start) {
                unsigned long addr;
-               down_write(&current->mm->mmap_sem);
-               addr = do_brk(start, end - start);
-               up_write(&current->mm->mmap_sem);
+               addr = vm_brk(start, end - start);
                if (BAD_ADDR(addr))
                        return addr;
        }
@@ -514,9 +512,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
                elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
 
                /* Map the last of the bss segment */
-               down_write(&current->mm->mmap_sem);
-               error = do_brk(elf_bss, last_bss - elf_bss);
-               up_write(&current->mm->mmap_sem);
+               error = vm_brk(elf_bss, last_bss - elf_bss);
                if (BAD_ADDR(error))
                        goto out_close;
        }
@@ -1072,11 +1068,8 @@ static int load_elf_library(struct file *file)
        len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
                            ELF_MIN_ALIGN - 1);
        bss = eppnt->p_memsz + eppnt->p_vaddr;
-       if (bss > len) {
-               down_write(&current->mm->mmap_sem);
-               do_brk(len, bss - len);
-               up_write(&current->mm->mmap_sem);
-       }
+       if (bss > len)
+               vm_brk(len, bss - len);
        error = 0;
 
 out_free_ph:
index d8738a4..bfee4ad 100644 (file)
@@ -1415,7 +1415,8 @@ out:
 
 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
 
-extern unsigned long do_brk(unsigned long, unsigned long);
+/* These take the mm semaphore themselves */
+extern unsigned long vm_brk(unsigned long, unsigned long);
 
 /* truncate.c */
 extern void truncate_inode_pages(struct address_space *, loff_t);
index a7bf6a3..df51891 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -240,6 +240,8 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
        return next;
 }
 
+static unsigned long do_brk(unsigned long addr, unsigned long len);
+
 SYSCALL_DEFINE1(brk, unsigned long, brk)
 {
        unsigned long rlim, retval;
@@ -2136,7 +2138,7 @@ static inline void verify_mm_writelocked(struct mm_struct *mm)
  *  anonymous maps.  eventually we may be able to do some
  *  brk-specific accounting here.
  */
-unsigned long do_brk(unsigned long addr, unsigned long len)
+static unsigned long do_brk(unsigned long addr, unsigned long len)
 {
        struct mm_struct * mm = current->mm;
        struct vm_area_struct * vma, * prev;
@@ -2232,7 +2234,17 @@ out:
        return addr;
 }
 
-EXPORT_SYMBOL(do_brk);
+unsigned long vm_brk(unsigned long addr, unsigned long len)
+{
+       struct mm_struct *mm = current->mm;
+       unsigned long ret;
+
+       down_write(&mm->mmap_sem);
+       ret = do_brk(addr, len);
+       up_write(&mm->mmap_sem);
+       return ret;
+}
+EXPORT_SYMBOL(vm_brk);
 
 /* Release all mmaps. */
 void exit_mmap(struct mm_struct *mm)
index f59e170..6341933 100644 (file)
@@ -1744,7 +1744,7 @@ void exit_mmap(struct mm_struct *mm)
        kleave("");
 }
 
-unsigned long do_brk(unsigned long addr, unsigned long len)
+unsigned long vm_brk(unsigned long addr, unsigned long len)
 {
        return -ENOMEM;
 }