Get rid of open-coding in ia64_brk()
Al Viro [Fri, 4 Dec 2009 00:59:24 +0000 (19:59 -0500)]
The comment in there used to be true, but these days do_brk() does
the arch-specific check that covers what we open-coded here.  So we
can use sys_brk() just fine, only need to do force_successful_syscall_return()
after it.

See commit 3a459756810912d2c2bf188cef566af255936b4d - that's when the
checks in do_brk() had been originally added.

Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/ia64/kernel/sys_ia64.c

index ae384a2..609d500 100644 (file)
@@ -100,51 +100,7 @@ sys_getpagesize (void)
 asmlinkage unsigned long
 ia64_brk (unsigned long brk)
 {
-       unsigned long rlim, retval, newbrk, oldbrk;
-       struct mm_struct *mm = current->mm;
-
-       /*
-        * Most of this replicates the code in sys_brk() except for an additional safety
-        * check and the clearing of r8.  However, we can't call sys_brk() because we need
-        * to acquire the mmap_sem before we can do the test...
-        */
-       down_write(&mm->mmap_sem);
-
-       if (brk < mm->end_code)
-               goto out;
-       newbrk = PAGE_ALIGN(brk);
-       oldbrk = PAGE_ALIGN(mm->brk);
-       if (oldbrk == newbrk)
-               goto set_brk;
-
-       /* Always allow shrinking brk. */
-       if (brk <= mm->brk) {
-               if (!do_munmap(mm, newbrk, oldbrk-newbrk))
-                       goto set_brk;
-               goto out;
-       }
-
-       /* Check against unimplemented/unmapped addresses: */
-       if ((newbrk - oldbrk) > RGN_MAP_LIMIT || REGION_OFFSET(newbrk) > RGN_MAP_LIMIT)
-               goto out;
-
-       /* Check against rlimit.. */
-       rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
-       if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
-               goto out;
-
-       /* Check against existing mmap mappings. */
-       if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
-               goto out;
-
-       /* Ok, looks good - let it rip. */
-       if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
-               goto out;
-set_brk:
-       mm->brk = brk;
-out:
-       retval = mm->brk;
-       up_write(&mm->mmap_sem);
+       unsigned long retval = sys_brk(brk);
        force_successful_syscall_return();
        return retval;
 }