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
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@ -3712,8 +3712,7 @@ vfs_bio_set_valid(struct buf *bp, int base, int size)
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void
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vfs_bio_clrbuf(struct buf *bp)
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{
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int i, j, mask;
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caddr_t sa, ea;
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int i, j, mask, sa, ea, slide;
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if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
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clrbuf(bp);
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@ -3731,30 +3730,33 @@ vfs_bio_clrbuf(struct buf *bp)
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if ((bp->b_pages[0]->valid & mask) == mask)
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goto unlock;
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if ((bp->b_pages[0]->valid & mask) == 0) {
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bzero(bp->b_data, bp->b_bufsize);
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pmap_zero_page_area(bp->b_pages[0], 0, bp->b_bufsize);
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bp->b_pages[0]->valid |= mask;
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goto unlock;
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}
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}
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ea = sa = bp->b_data;
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for(i = 0; i < bp->b_npages; i++, sa = ea) {
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ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE);
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ea = (caddr_t)(vm_offset_t)ulmin(
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(u_long)(vm_offset_t)ea,
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(u_long)(vm_offset_t)bp->b_data + bp->b_bufsize);
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sa = bp->b_offset & PAGE_MASK;
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slide = 0;
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for (i = 0; i < bp->b_npages; i++, sa = 0) {
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slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize);
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ea = slide & PAGE_MASK;
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if (ea == 0)
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ea = PAGE_SIZE;
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if (bp->b_pages[i] == bogus_page)
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continue;
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j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
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j = sa / DEV_BSIZE;
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mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
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VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[i]->object);
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if ((bp->b_pages[i]->valid & mask) == mask)
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continue;
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if ((bp->b_pages[i]->valid & mask) == 0)
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bzero(sa, ea - sa);
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pmap_zero_page_area(bp->b_pages[i], sa, ea - sa);
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else {
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for (; sa < ea; sa += DEV_BSIZE, j++) {
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if ((bp->b_pages[i]->valid & (1 << j)) == 0)
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bzero(sa, DEV_BSIZE);
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if ((bp->b_pages[i]->valid & (1 << j)) == 0) {
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pmap_zero_page_area(bp->b_pages[i],
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sa, DEV_BSIZE);
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}
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}
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}
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bp->b_pages[i]->valid |= mask;
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