void freeb(struct block *b)
{
void *dead = (void *)Bdead;
if (b == NULL)
return;
free_block_extra(b);
/*
* drivers which perform non cache coherent DMA manage their own buffer
* pool of uncached buffers and provide their own free routine.
*/
if (b->free) {
b->free(b);
return;
}
if (b->flag & BINTR) {
/* subtracting the size of b */
atomic_add(&ialloc_bytes, -(b->lim - b->base));
}
/* poison the block in case someone is still holding onto it */
b->next = dead;
b->rp = dead;
b->wp = dead;
b->lim = dead;
b->base = dead;
kfree(b);
}
/* Frees a block, returning its size (len, not alloc) */
size_t freeb(struct block *b)
{
void *dead = (void *)Bdead;
size_t ret;
if (b == NULL)
return 0;
ret = BLEN(b);
free_block_extra(b);
/*
* drivers which perform non cache coherent DMA manage their own buffer
* pool of uncached buffers and provide their own free routine.
*/
if (b->free) {
b->free(b);
return ret;
}
/* poison the block in case someone is still holding onto it */
b->next = dead;
b->rp = dead;
b->wp = dead;
b->lim = dead;
b->base = dead;
kfree(b);
return ret;
}
/* Adjust block @bp so that its size is exactly @len.
* If the size is increased, fill in the new contents with zeros.
* If the size is decreased, discard some of the old contents at the tail. */
struct block *adjustblock(struct block *bp, int len)
{
struct extra_bdata *ebd;
void *buf;
int i;
if (len < 0) {
freeb(bp);
return NULL;
}
if (len == BLEN(bp))
return bp;
/* Shrink within block main body. */
if (len <= BHLEN(bp)) {
free_block_extra(bp);
bp->wp = bp->rp + len;
QDEBUG checkb(bp, "adjustblock 1");
return bp;
}
/* Need to grow. */
if (len > BLEN(bp)) {
/* Grow within block main body. */
if (bp->extra_len == 0 && bp->rp + len <= bp->lim) {
memset(bp->wp, 0, len - BLEN(bp));
bp->wp = bp->rp + len;
QDEBUG checkb(bp, "adjustblock 2");
return bp;
}
/* Grow with extra data buffers. */
buf = kzmalloc(len - BLEN(bp), MEM_WAIT);
block_append_extra(bp, (uintptr_t)buf, 0, len - BLEN(bp), MEM_WAIT);
QDEBUG checkb(bp, "adjustblock 3");
return bp;
}
/* Shrink extra data buffers.
* len is how much of ebd we need to keep.
* extra_len is re-accumulated. */
assert(bp->extra_len > 0);
len -= BHLEN(bp);
bp->extra_len = 0;
for (i = 0; i < bp->nr_extra_bufs; i++) {
ebd = &bp->extra_data[i];
if (len <= ebd->len)
break;
len -= ebd->len;
bp->extra_len += ebd->len;
}
/* If len becomes zero, extra_data[i] should be freed. */
if (len > 0) {
ebd = &bp->extra_data[i];
ebd->len = len;
bp->extra_len += ebd->len;
i++;
}
for (; i < bp->nr_extra_bufs; i++) {
ebd = &bp->extra_data[i];
if (ebd->base)
kfree((void*)ebd->base);
ebd->base = ebd->off = ebd->len = 0;
}
QDEBUG checkb(bp, "adjustblock 4");
return bp;
}