From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751203AbWD3Rgo (ORCPT ); Sun, 30 Apr 2006 13:36:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751212AbWD3RdJ (ORCPT ); Sun, 30 Apr 2006 13:33:09 -0400 Received: from host157-96.pool873.interbusiness.it ([87.3.96.157]:45522 "EHLO zion.home.lan") by vger.kernel.org with ESMTP id S1751203AbWD3Rcn (ORCPT ); Sun, 30 Apr 2006 13:32:43 -0400 Message-Id: <20060430173023.339578000@zion.home.lan> References: <20060430172953.409399000@zion.home.lan> User-Agent: quilt/0.44-1 Date: Sun, 30 Apr 2006 19:29:58 +0200 From: blaisorblade@yahoo.it To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Paolo Blaisorblade Giarrusso Subject: [patch 05/14] remap_file_pages protection support: cleanup syscall checks Content-Disposition: inline; filename=rfp/05-rfp-cleanup-sc-check.diff Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo 'Blaisorblade' Giarrusso This patch reorganizes the code only, without differences in behaviour. It makes the code more readable on its own, and is needed for next patches. I've split this out to avoid cluttering real patches. *) remap_file_pages protection support: use EOVERFLOW ret code Use -EOVERFLOW ("Value too large for defined data type") rather than -EINVAL when we cannot store the file offset in the PTE. Signed-off-by: Paolo 'Blaisorblade' Giarrusso Index: linux-2.6.git/mm/fremap.c =================================================================== --- linux-2.6.git.orig/mm/fremap.c +++ linux-2.6.git/mm/fremap.c @@ -140,7 +140,7 @@ out: * future. */ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, - unsigned long __prot, unsigned long pgoff, unsigned long flags) + unsigned long prot, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; struct address_space *mapping; @@ -148,9 +148,10 @@ asmlinkage long sys_remap_file_pages(uns struct vm_area_struct *vma; int err = -EINVAL; int has_write_lock = 0; + pgprot_t pgprot; - if (__prot) - return err; + if (prot) + goto out; /* * Sanitize the syscall parameters: */ @@ -159,17 +160,19 @@ asmlinkage long sys_remap_file_pages(uns /* Does the address range wrap, or is the span zero-sized? */ if (start + size <= start) - return err; + goto out; /* Can we represent this offset inside this architecture's pte's? */ #if PTE_FILE_MAX_BITS < BITS_PER_LONG - if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS)) - return err; + if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS)) { + err = -EOVERFLOW; + goto out; + } #endif /* We need down_write() to change vma->vm_flags. */ down_read(&mm->mmap_sem); - retry: +retry: vma = find_vma(mm, start); /* @@ -178,12 +181,21 @@ asmlinkage long sys_remap_file_pages(uns * the single existing vma. vm_private_data is used as a * swapout cursor in a VM_NONLINEAR vma. */ - if (vma && (vma->vm_flags & VM_SHARED) && - (!vma->vm_private_data || (vma->vm_flags & VM_NONLINEAR)) && - vma->vm_ops && vma->vm_ops->populate && - end > start && start >= vma->vm_start && - end <= vma->vm_end) { + if (!vma) + goto out_unlock; + + if (!(vma->vm_flags & VM_SHARED)) + goto out_unlock; + + if (!vma->vm_ops || !vma->vm_ops->populate) + goto out_unlock; + if (end <= start || start < vma->vm_start || end > vma->vm_end) + goto out_unlock; + + pgprot = vma->vm_page_prot; + + if (!vma->vm_private_data || (vma->vm_flags & VM_NONLINEAR)) { /* Must set VM_NONLINEAR before any pages are populated. */ if (pgoff != linear_page_index(vma, start) && !(vma->vm_flags & VM_NONLINEAR)) { @@ -203,9 +215,8 @@ asmlinkage long sys_remap_file_pages(uns spin_unlock(&mapping->i_mmap_lock); } - err = vma->vm_ops->populate(vma, start, size, - vma->vm_page_prot, - pgoff, flags & MAP_NONBLOCK); + err = vma->vm_ops->populate(vma, start, size, pgprot, pgoff, + flags & MAP_NONBLOCK); /* * We would like to clear VM_NONLINEAR, in the case when @@ -214,11 +225,14 @@ asmlinkage long sys_remap_file_pages(uns * successful populate, and have no way to upgrade sem. */ } + +out_unlock: if (likely(!has_write_lock)) up_read(&mm->mmap_sem); else up_write(&mm->mmap_sem); +out: return err; } -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade