Function dump_append

freebsd/kern/kern_shutdown.c:1643–1658

* Write to the dump device starting at dumpoff. When compression is enabled, * writes to the device will be performed using a callback that gets invoked * when the compression stream's output buffer is full. */

 * when the compression stream's output buffer is full.
 */
int
dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
    size_t length)
{
	void *buf;

	if (di->kdcomp != NULL) {
		/* Bounce through a buffer to avoid CRC errors. */
		if (length > di->maxiosize)
			return (EINVAL);
		buf = di->kdcomp->kdc_buf;
		memmove(buf, virtual, length);
		return (compressor_write(di->kdcomp->kdc_stream, buf, length));
	}
	return (_dump_append(di, virtual, physical, length));
}

/*
 * Write to the dump device at the specified offset.