From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752705Ab2LGIPc (ORCPT ); Fri, 7 Dec 2012 03:15:32 -0500 Received: from mail-vb0-f46.google.com ([209.85.212.46]:47370 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884Ab2LGIPb (ORCPT ); Fri, 7 Dec 2012 03:15:31 -0500 MIME-Version: 1.0 In-Reply-To: References: <1354810175-4338-1-git-send-email-js1304@gmail.com> <1354810175-4338-2-git-send-email-js1304@gmail.com> Date: Fri, 7 Dec 2012 16:15:30 +0800 Message-ID: Subject: Re: [RFC PATCH 1/8] mm, vmalloc: change iterating a vmlist to find_vm_area() From: Bob Liu To: Pekka Enberg Cc: Joonsoo Kim , Andrew Morton , Russell King , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kexec@lists.infradead.org, Chris Metcalf , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 7, 2012 at 3:44 PM, Pekka Enberg wrote: > On Thu, Dec 6, 2012 at 6:09 PM, Joonsoo Kim wrote: >> The purpose of iterating a vmlist is finding vm area with specific >> virtual address. find_vm_area() is provided for this purpose >> and more efficient, because it uses a rbtree. >> So change it. > > You no longer take the 'vmlist_lock'. This is safe, because...? > I think it's because find_vm_area() -> find_vmap_area() will use vmap_area_lock instead. >> Cc: Chris Metcalf >> Cc: Guan Xuetao >> Cc: Thomas Gleixner >> Cc: Ingo Molnar >> Cc: "H. Peter Anvin" >> Signed-off-by: Joonsoo Kim >> >> diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c >> index de0de0c..862782d 100644 >> --- a/arch/tile/mm/pgtable.c >> +++ b/arch/tile/mm/pgtable.c >> @@ -592,12 +592,7 @@ void iounmap(volatile void __iomem *addr_in) >> in parallel. Reuse of the virtual address is prevented by >> leaving it in the global lists until we're done with it. >> cpa takes care of the direct mappings. */ >> - read_lock(&vmlist_lock); >> - for (p = vmlist; p; p = p->next) { >> - if (p->addr == addr) >> - break; >> - } >> - read_unlock(&vmlist_lock); >> + p = find_vm_area((void *)addr); >> >> if (!p) { >> pr_err("iounmap: bad address %p\n", addr); >> diff --git a/arch/unicore32/mm/ioremap.c b/arch/unicore32/mm/ioremap.c >> index b7a6055..13068ee 100644 >> --- a/arch/unicore32/mm/ioremap.c >> +++ b/arch/unicore32/mm/ioremap.c >> @@ -235,7 +235,7 @@ EXPORT_SYMBOL(__uc32_ioremap_cached); >> void __uc32_iounmap(volatile void __iomem *io_addr) >> { >> void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); >> - struct vm_struct **p, *tmp; >> + struct vm_struct *vm; >> >> /* >> * If this is a section based mapping we need to handle it >> @@ -244,17 +244,10 @@ void __uc32_iounmap(volatile void __iomem *io_addr) >> * all the mappings before the area can be reclaimed >> * by someone else. >> */ >> - write_lock(&vmlist_lock); >> - for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { >> - if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { >> - if (tmp->flags & VM_UNICORE_SECTION_MAPPING) { >> - unmap_area_sections((unsigned long)tmp->addr, >> - tmp->size); >> - } >> - break; >> - } >> - } >> - write_unlock(&vmlist_lock); >> + vm = find_vm_area(addr); >> + if (vm && (vm->flags & VM_IOREMAP) && >> + (vm->flags & VM_UNICORE_SECTION_MAPPING)) >> + unmap_area_sections((unsigned long)vm->addr, vm->size); >> >> vunmap(addr); >> } >> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c >> index 78fe3f1..9a1e658 100644 >> --- a/arch/x86/mm/ioremap.c >> +++ b/arch/x86/mm/ioremap.c >> @@ -282,12 +282,7 @@ void iounmap(volatile void __iomem *addr) >> in parallel. Reuse of the virtual address is prevented by >> leaving it in the global lists until we're done with it. >> cpa takes care of the direct mappings. */ >> - read_lock(&vmlist_lock); >> - for (p = vmlist; p; p = p->next) { >> - if (p->addr == (void __force *)addr) >> - break; >> - } >> - read_unlock(&vmlist_lock); >> + p = find_vm_area((void __force *)addr); >> >> if (!p) { >> printk(KERN_ERR "iounmap: bad address %p\n", addr); >> -- >> 1.7.9.5 -- Thanks, --Bob