From owner-svn-src-all@FreeBSD.ORG Sat May 9 08:30:44 2009 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5CA38106566C; Sat, 9 May 2009 08:30:44 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 4B7D38FC1D; Sat, 9 May 2009 08:30:44 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id n498UiDf016519; Sat, 9 May 2009 08:30:44 GMT (envelope-from alc@svn.freebsd.org) Received: (from alc@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id n498Ui1D016518; Sat, 9 May 2009 08:30:44 GMT (envelope-from alc@svn.freebsd.org) Message-Id: <200905090830.n498Ui1D016518@svn.freebsd.org> From: Alan Cox Date: Sat, 9 May 2009 08:30:44 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r191935 - head/sys/vm X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 May 2009 08:30:44 -0000 Author: alc Date: Sat May 9 08:30:44 2009 New Revision: 191935 URL: http://svn.freebsd.org/changeset/base/191935 Log: Fix a race involving vnode_pager_input_smlfs(). Specifically, in the case that vnode_pager_input_smlfs() zeroes the page, it should not mark the page as valid until after the page is zeroed. Otherwise, the page could be mapped for read access (e.g., by vm_map_pmap_enter()) before the page is zeroed. Reviewed by: tegge Eliminate gratuitous clearing of the page's dirty mask by vnode_pager_input_smlfs(). Instead, assert that the page is clean. Reviewed by: tegge Eliminate some blank lines. Eliminate pointless calls to pmap_clear_modify() and vm_page_undirty() from vnode_pager_input_old(). The page is not mapped. Therefore, it cannot have any page table entries that are modified. Eliminate an incorrect comment from vnode_pager_generic_getpages(). Modified: head/sys/vm/vnode_pager.c Modified: head/sys/vm/vnode_pager.c ============================================================================== --- head/sys/vm/vnode_pager.c Sat May 9 05:45:13 2009 (r191934) +++ head/sys/vm/vnode_pager.c Sat May 9 08:30:44 2009 (r191935) @@ -476,7 +476,7 @@ vnode_pager_input_smlfs(object, m) vm_object_t object; vm_page_t m; { - int i; + int bits, i; struct vnode *vp; struct bufobj *bo; struct buf *bp; @@ -498,7 +498,8 @@ vnode_pager_input_smlfs(object, m) for (i = 0; i < PAGE_SIZE / bsize; i++) { vm_ooffset_t address; - if (vm_page_bits(i * bsize, bsize) & m->valid) + bits = vm_page_bits(i * bsize, bsize); + if (m->valid & bits) continue; address = IDX_TO_OFF(m->pindex) + i * bsize; @@ -543,30 +544,21 @@ vnode_pager_input_smlfs(object, m) relpbuf(bp, &vnode_pbuf_freecnt); if (error) break; - - VM_OBJECT_LOCK(object); - vm_page_lock_queues(); - vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); - vm_page_unlock_queues(); - VM_OBJECT_UNLOCK(object); - } else { - VM_OBJECT_LOCK(object); - vm_page_lock_queues(); - vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); - vm_page_unlock_queues(); - VM_OBJECT_UNLOCK(object); + } else bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); - } + KASSERT((m->dirty & bits) == 0, + ("vnode_pager_input_smlfs: page %p is dirty", m)); + VM_OBJECT_LOCK(object); + m->valid |= bits; + VM_OBJECT_UNLOCK(object); } sf_buf_free(sf); if (error) { return VM_PAGER_ERROR; } return VM_PAGER_OK; - } - /* * old style vnode pager input routine */ @@ -627,10 +619,7 @@ vnode_pager_input_old(object, m) VM_OBJECT_LOCK(object); } - vm_page_lock_queues(); - pmap_clear_modify(m); - vm_page_undirty(m); - vm_page_unlock_queues(); + KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); if (!error) m->valid = VM_PAGE_BITS_ALL; return error ? VM_PAGER_ERROR : VM_PAGER_OK; @@ -960,8 +949,6 @@ vnode_pager_generic_getpages(vp, m, byte */ vm_page_set_validclean(mt, 0, object->un_pager.vnp.vnp_size - tfoff); - /* handled by vm_fault now */ - /* vm_page_zero_invalid(mt, FALSE); */ } if (i != reqpage) {