powerpc/vdso: Simplify arch_setup_additional_pages() exit

To simplify arch_setup_additional_pages() exit, rename
it __arch_setup_additional_pages() and create a caller
arch_setup_additional_pages() which does the locking.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/603c1d039d3f928ee95e547fcd2219fcf4c3b514.1601197618.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 448ecaa..a976c5e 100644 (file)
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -122,7 +122,7 @@ struct lib64_elfinfo
  * This is called from binfmt_elf, we create the special vma for the
  * vDSO and insert it into the mm struct tree
  */
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
        struct mm_struct *mm = current->mm;
        struct page **vdso_pagelist;
@@ -130,9 +130,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
        unsigned long vdso_base;
        int rc;
 
-       if (!vdso_ready)
-               return 0;
-
        if (is_32bit_task()) {
                vdso_pagelist = vdso32_pagelist;
                vdso_size = &vdso32_end - &vdso32_start;
@@ -148,8 +145,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                vdso_base = 0;
        }
 
-       current->mm->context.vdso_base = 0;
-
        /* Add a page to the vdso size for the data page */
        vdso_size += PAGE_SIZE;
 
@@ -159,15 +154,11 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
         * and end up putting it elsewhere.
         * Add enough to the size so that the result can be aligned.
         */
-       if (mmap_write_lock_killable(mm))
-               return -EINTR;
        vdso_base = get_unmapped_area(NULL, vdso_base,
                                      vdso_size + ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
                                      0, 0);
-       if (IS_ERR_VALUE(vdso_base)) {
-               rc = vdso_base;
-               goto fail_mmapsem;
-       }
+       if (IS_ERR_VALUE(vdso_base))
+               return vdso_base;
 
        /* Add required alignment. */
        vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
@@ -193,15 +184,26 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                                     VM_READ|VM_EXEC|
                                     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
                                     vdso_pagelist);
-       if (rc) {
-               current->mm->context.vdso_base = 0;
-               goto fail_mmapsem;
-       }
+       return rc;
+}
 
-       mmap_write_unlock(mm);
-       return 0;
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+       struct mm_struct *mm = current->mm;
+       int rc;
+
+       mm->context.vdso_base = 0;
+
+       if (!vdso_ready)
+               return 0;
+
+       if (mmap_write_lock_killable(mm))
+               return -EINTR;
+
+       rc = __arch_setup_additional_pages(bprm, uses_interp);
+       if (rc)
+               mm->context.vdso_base = 0;
 
- fail_mmapsem:
        mmap_write_unlock(mm);
        return rc;
 }