kern/src/ns/allocplan9block.c

#include <vfs.h>
#include <kfs.h>
#include <slab.h>
#include <kmalloc.h>
#include <kref.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <error.h>
#include <cpio.h>
#include <pmap.h>
#include <smp.h>

enum {
	Hdrspc = 64,				/* leave room for high-level headers */
	Bdead = 0x51494F42,	/* "QIOB" */
	BLOCKALIGN = 32,	/* known to be good for all systems. */
};

static atomic_t ialloc_bytes = 0;

static struct block *_allocb(int size)
{
	struct block *b;
	uint8_t *p;
	int n;

	n = BLOCKALIGN + ROUNDUP(size + Hdrspc, BLOCKALIGN) + sizeof(struct block);
	if ((p = kzmalloc(n, KMALLOC_WAIT)) == NULL)
		return NULL;

	b = (struct block *)(p + n - sizeof(struct block));	/* block at end of allocated space */
	b->base = p;

	b->next = NULL;
	b->list = NULL;
	b->free = 0;
	b->flag = 0;

	/* align base and bounds of data */
	b->lim = (uint8_t *) ((uintptr_t) b & ~(BLOCKALIGN - 1));

	/* align start of writable data, leaving space below for added headers */
	b->rp = b->lim - ROUNDUP(size, BLOCKALIGN);
	b->wp = b->rp;

	if (b->rp < b->base || b->lim - b->rp < size)
		panic("_allocb");

	return b;
}

struct block *allocb(int size)
{
	struct block *b;

	/*
	 * Check in a process and wait until successful.
	 * Can still error out of here, though.
	 * should only be called from user context.
	 */
	if ((b = _allocb(size)) == NULL) {
		panic("allocb: no memory for %d bytes\n", size);
	}

	return b;
}

/* interrupt context allocb. */
struct block *iallocb(int size)
{
	struct block *b;
	static int m1, m2, mp;

	if ((b = _allocb(size)) == NULL) {
		if ((m2++ % 10000) == 0) {
			if (mp++ > 1000) {
				panic("iallocb");
			}
			printd("iallocb: no memory \n");
		}
		return NULL;
	}
	b->flag = BINTR;

	atomic_add(&ialloc_bytes, b->lim - b->base);

	return b;
}

void freeb(struct block *b)
{
	void *dead = (void *)Bdead;
	uint8_t *p;

	if (b == NULL)
		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) {
		b->free(b);
		return;
	}
	if (b->flag & BINTR) {
		/* subtracting the size of b */
		atomic_add(&ialloc_bytes, -(b->lim - b->base));
	}

	p = 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(p);
}

void checkb(struct 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) {
		printd("checkb: base %#p lim %#p next %#p\n", b->base, b->lim, b->next);
		printd("checkb: rp %#p wp %#p\n", b->rp, b->wp);
		panic("checkb dead: %s\n", 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);
}

void iallocsummary(void)
{
	printd("ialloc %lu\n", atomic_read(&ialloc_bytes));
}