From e4eb1ff61b323d6141614e5458a1f53c7046ff8e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 20 Apr 2012 15:35:40 -0700 Subject: [PATCH] VM: add "vm_brk()" helper function 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 --- arch/x86/ia32/ia32_aout.c | 20 +++++--------------- fs/binfmt_aout.c | 20 +++++--------------- fs/binfmt_elf.c | 15 ++++----------- include/linux/mm.h | 3 ++- mm/mmap.c | 16 ++++++++++++++-- mm/nommu.c | 2 +- 6 files changed, 31 insertions(+), 45 deletions(-) diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c index d511d95..b6817ee 100644 --- a/arch/x86/ia32/ia32_aout.c +++ b/arch/x86/ia32/ia32_aout.c @@ -119,9 +119,7 @@ static void set_brk(unsigned long start, unsigned long end) end = PAGE_ALIGN(end); if (end <= start) return; - down_write(¤t->mm->mmap_sem); - do_brk(start, end - start); - up_write(¤t->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(¤t->mm->mmap_sem); - error = do_brk(text_addr & PAGE_MASK, map_size); - up_write(¤t->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(¤t->mm->mmap_sem); - do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); - up_write(¤t->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(¤t->mm->mmap_sem); - do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); - up_write(¤t->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(¤t->mm->mmap_sem); - error = do_brk(start_addr + len, bss - len); - up_write(¤t->mm->mmap_sem); + error = vm_brk(start_addr + len, bss - len); retval = error; if (error != start_addr + len) goto out; diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c index 2eb12f1..8852749 100644 --- a/fs/binfmt_aout.c +++ b/fs/binfmt_aout.c @@ -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(¤t->mm->mmap_sem); - addr = do_brk(start, end - start); - up_write(¤t->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(¤t->mm->mmap_sem); - error = do_brk(text_addr & PAGE_MASK, map_size); - up_write(¤t->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(¤t->mm->mmap_sem); - do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); - up_write(¤t->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(¤t->mm->mmap_sem); - do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); - up_write(¤t->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(¤t->mm->mmap_sem); - error = do_brk(start_addr + len, bss - len); - up_write(¤t->mm->mmap_sem); + error = vm_brk(start_addr + len, bss - len); retval = error; if (error != start_addr + len) goto out; diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 48ffb3d..0708a0b 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -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(¤t->mm->mmap_sem); - addr = do_brk(start, end - start); - up_write(¤t->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(¤t->mm->mmap_sem); - error = do_brk(elf_bss, last_bss - elf_bss); - up_write(¤t->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(¤t->mm->mmap_sem); - do_brk(len, bss - len); - up_write(¤t->mm->mmap_sem); - } + if (bss > len) + vm_brk(len, bss - len); error = 0; out_free_ph: diff --git a/include/linux/mm.h b/include/linux/mm.h index d8738a4..bfee4ad 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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); diff --git a/mm/mmap.c b/mm/mmap.c index a7bf6a3..df51891 100644 --- 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) diff --git a/mm/nommu.c b/mm/nommu.c index f59e170..6341933 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -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; } -- 1.7.10.4