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author | Alan Cox <alc@FreeBSD.org> | 2009-05-09 08:30:44 +0000 |
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committer | Alan Cox <alc@FreeBSD.org> | 2009-05-09 08:30:44 +0000 |
commit | 0d53a17bde39ba28d38165317ae4b0a6098a8e78 (patch) | |
tree | fd771168b6dc023886bb944cc8f9f58bba502563 /sys/vm | |
parent | 126b14f7e87fe56edcdf33be5ff6925de5c0290c (diff) | |
download | src-0d53a17bde39ba28d38165317ae4b0a6098a8e78.tar.gz src-0d53a17bde39ba28d38165317ae4b0a6098a8e78.zip |
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().
Notes
Notes:
svn path=/head/; revision=191935
Diffstat (limited to 'sys/vm')
-rw-r--r-- | sys/vm/vnode_pager.c | 33 |
1 files changed, 10 insertions, 23 deletions
diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c index 19c2c336517f..3d6909b29377 100644 --- a/sys/vm/vnode_pager.c +++ b/sys/vm/vnode_pager.c @@ -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, bytecount, reqpage) */ 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) { |