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Several changes to vfs_bio_clrbuf():

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Provide a more descriptive comment.

Eliminate dead code.  The page cannot possibly have PG_ZERO set.

Eliminate unnecessary blank lines.

Reviewed by:	tegge
This commit is contained in:
alc 2009-05-17 23:25:53 +00:00
parent f0d016550f
commit c8b00d493e
1 changed files with 11 additions and 13 deletions
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24
sys/kern/vfs_bio.c
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@ -3706,24 +3706,25 @@ vfs_bio_set_validclean(struct buf *bp, int base, int size)
/*
* vfs_bio_clrbuf:
*
* clear a buffer. This routine essentially fakes an I/O, so we need
* to clear BIO_ERROR and B_INVAL.
* If the specified buffer is a non-VMIO buffer, clear the entire
* buffer. If the specified buffer is a VMIO buffer, clear and
* validate only the previously invalid portions of the buffer.
* This routine essentially fakes an I/O, so we need to clear
* BIO_ERROR and B_INVAL.
*
* Note that while we only theoretically need to clear through b_bcount,
* we go ahead and clear through b_bufsize.
*/
void
vfs_bio_clrbuf(struct buf *bp)
{
int i, j, mask = 0;
int i, j, mask;
caddr_t sa, ea;
if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
clrbuf(bp);
return;
}
bp->b_flags &= ~B_INVAL;
bp->b_ioflags &= ~BIO_ERROR;
VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
@ -3735,8 +3736,7 @@ vfs_bio_clrbuf(struct buf *bp)
VM_OBJECT_LOCK_ASSERT(bp->b_pages[0]->object, MA_OWNED);
if ((bp->b_pages[0]->valid & mask) == mask)
goto unlock;
if (((bp->b_pages[0]->flags & PG_ZERO) == 0) &&
((bp->b_pages[0]->valid & mask) == 0)) {
if ((bp->b_pages[0]->valid & mask) == 0) {
bzero(bp->b_data, bp->b_bufsize);
bp->b_pages[0]->valid |= mask;
goto unlock;
@ -3755,13 +3755,11 @@ vfs_bio_clrbuf(struct buf *bp)
VM_OBJECT_LOCK_ASSERT(bp->b_pages[i]->object, MA_OWNED);
if ((bp->b_pages[i]->valid & mask) == mask)
continue;
if ((bp->b_pages[i]->valid & mask) == 0) {
if ((bp->b_pages[i]->flags & PG_ZERO) == 0)
bzero(sa, ea - sa);
} else {
if ((bp->b_pages[i]->valid & mask) == 0)
bzero(sa, ea - sa);
else {
for (; sa < ea; sa += DEV_BSIZE, j++) {
if (((bp->b_pages[i]->flags & PG_ZERO) == 0) &&
(bp->b_pages[i]->valid & (1 << j)) == 0)
if ((bp->b_pages[i]->valid & (1 << j)) == 0)
bzero(sa, DEV_BSIZE);
}
}