#include	"u.h"#include	"lib.h"#include	"dat.h"#include	"fns.h"#include	"error.h" enum{	Hdrspc		= 64,		/* leave room for high-level headers */	Tlrspc		= 16,		/* extra room at the end for pad/crc/mac */	Bdead		= 0x51494F42,	/* "QIOB" */}; static Block*_allocb(int size){	Block *b;	uintptr addr; 	size += Tlrspc;	if((b = mallocz(sizeof(Block)+size+Hdrspc, 0)) == nil)		return nil; 	b->next = nil;	b->list = nil;	b->free = nil;	b->flag = 0; 	/* align start of data portion by rounding up */	addr = (uintptr)b;	addr = ROUND(addr + sizeof(Block), BLOCKALIGN);	b->base = (uchar*)addr; 	/* align end of data portion by rounding down */	b->lim = (uchar*)b + sizeof(Block)+size+Hdrspc;	addr = (uintptr)b->lim;	addr &= ~(BLOCKALIGN-1);	b->lim = (uchar*)addr; 	/* leave sluff at beginning for added headers */	b->rp = b->lim - ROUND(size, BLOCKALIGN);	if(b->rp < b->base)		panic("_allocb");	b->wp = b->rp; 	return b;} Block*allocb(int size){	Block *b; 	/*	 * Check in a process and wait until successful.	 */	if(up == nil)		panic("allocb without up: %#p", getcallerpc(&size));	if((b = _allocb(size)) == nil)		panic("allocb: no memory for %d bytes", size);	setmalloctag(b, getcallerpc(&size)); 	return b;} Block*iallocb(int size){	Block *b; 	if((b = _allocb(size)) == nil)		panic("iallocb: no memory for %d bytes", size);	setmalloctag(b, getcallerpc(&size));	b->flag = BINTR; 	return b;} voidfreeb(Block *b){	void *dead = (void*)Bdead; 	if(b == nil)		return; 	/*	 * drivers which perform non cache coherent DMA manage their own buffer	 * pool of uncached buffers and provide their own free routine.	 */	if(b->free != nil) {		b->free(b);		return;	} 	/* 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; 	free(b);} voidcheckb(Block *b, char *msg){	void *dead = (void*)Bdead; 	if(b == dead)		panic("checkb b %s %#p", msg, b);	if(b->base == dead || b->lim == dead || b->next == dead	  || b->rp == dead || b->wp == dead){		print("checkb: base %#p lim %#p next %#p\n",			b->base, b->lim, b->next);		print("checkb: rp %#p wp %#p\n", b->rp, b->wp);		panic("checkb dead: %s", msg);	} 	if(b->base > b->lim)		panic("checkb 0 %s %#p %#p", msg, b->base, b->lim);	if(b->rp < b->base)		panic("checkb 1 %s %#p %#p", msg, b->base, b->rp);	if(b->wp < b->base)		panic("checkb 2 %s %#p %#p", msg, b->base, b->wp);	if(b->rp > b->lim)		panic("checkb 3 %s %#p %#p", msg, b->rp, b->lim);	if(b->wp > b->lim)		panic("checkb 4 %s %#p %#p", msg, b->wp, b->lim);}