Author: kib
Date: Thu Mar 14 19:48:25 2013
New Revision: 248276
URL: http://svnweb.freebsd.org/changeset/base/248276
Log:
Rewrite the vfs_bio_clrbuf(9) to not access the b_data for B_VMIO
buffers directly, use pmap_zero_page_area(9) for each zeroing page
region instead.
Sponsored by: The FreeBSD Foundation
Tested by: pho
MFC after: 2 weeks
Modified:
head/sys/kern/vfs_bio.c
Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c Thu Mar 14 19:36:20 2013 (r248275)
+++ head/sys/kern/vfs_bio.c Thu Mar 14 19:48:25 2013 (r248276)
@@ -3712,8 +3712,7 @@ vfs_bio_set_valid(struct buf *bp, int ba
void
vfs_bio_clrbuf(struct buf *bp)
{
- int i, j, mask;
- caddr_t sa, ea;
+ int i, j, mask, sa, ea, slide;
if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
clrbuf(bp);
@@ -3731,30 +3730,33 @@ vfs_bio_clrbuf(struct buf *bp)
if ((bp->b_pages[0]->valid & mask) == mask)
goto unlock;
if ((bp->b_pages[0]->valid & mask) == 0) {
- bzero(bp->b_data, bp->b_bufsize);
+ pmap_zero_page_area(bp->b_pages[0], 0, bp->b_bufsize);
bp->b_pages[0]->valid |= mask;
goto unlock;
}
}
- ea = sa = bp->b_data;
- for(i = 0; i < bp->b_npages; i++, sa = ea) {
- ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE);
- ea = (caddr_t)(vm_offset_t)ulmin(
- (u_long)(vm_offset_t)ea,
- (u_long)(vm_offset_t)bp->b_data + bp->b_bufsize);
+ sa = bp->b_offset & PAGE_MASK;
+ slide = 0;
+ for (i = 0; i < bp->b_npages; i++, sa = 0) {
+ slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize);
+ ea = slide & PAGE_MASK;
+ if (ea == 0)
+ ea = PAGE_SIZE;
if (bp->b_pages[i] == bogus_page)
continue;
- j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
+ j = sa / DEV_BSIZE;
mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[i]->object);
if ((bp->b_pages[i]->valid & mask) == mask)
continue;
if ((bp->b_pages[i]->valid & mask) == 0)
- bzero(sa, ea - sa);
+ pmap_zero_page_area(bp->b_pages[i], sa, ea - sa);
else {
for (; sa < ea; sa += DEV_BSIZE, j++) {
- if ((bp->b_pages[i]->valid & (1 << j)) == 0)
- bzero(sa, DEV_BSIZE);
+ if ((bp->b_pages[i]->valid & (1 << j)) == 0) {
+ pmap_zero_page_area(bp->b_pages[i],
+ sa, DEV_BSIZE);
+ }
}
}
bp->b_pages[i]->valid |= mask;
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