path: root/drivers/block/aoe/aoecmd.c

/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoecmd.c
 * Filesystem request handling methods
 */

#include <linux/ata.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/genhd.h>
#include <linux/moduleparam.h>
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <net/net_namespace.h>
#include <asm/unaligned.h>
#include <linux/uio.h>
#include "aoe.h"

#define MAXIOC (8192)	/* default meant to avoid most soft lockups */

static void ktcomplete(struct frame *, struct sk_buff *);

static struct buf *nextbuf(struct aoedev *);

static int aoe_deadsecs = 60 * 3;
module_param(aoe_deadsecs, int, 0644);
MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");

static int aoe_maxout = 16;
module_param(aoe_maxout, int, 0644);
MODULE_PARM_DESC(aoe_maxout,
	"Only aoe_maxout outstanding packets for every MAC on eX.Y.");

static wait_queue_head_t ktiowq;
static struct ktstate kts;

/* io completion queue */
static struct {
	struct list_head head;
	spinlock_t lock;
} iocq;

static struct sk_buff *
new_skb(ulong len)
{
	struct sk_buff *skb;

	skb = alloc_skb(len, GFP_ATOMIC);
	if (skb) {
		skb_reset_mac_header(skb);
		skb_reset_network_header(skb);
		skb->protocol = __constant_htons(ETH_P_AOE);
		skb_checksum_none_assert(skb);
	}
	return skb;
}

static struct frame *
getframe_deferred(struct aoedev *d, u32 tag)
{
	struct list_head *head, *pos, *nx;
	struct frame *f;

	head = &d->rexmitq;
	list_for_each_safe(pos, nx, head) {
		f = list_entry(pos, struct frame, head);
		if (f->tag == tag) {
			list_del(pos);
			return f;
		}
	}
	return NULL;
}

static struct frame *
getframe(struct aoedev *d, u32 tag)
{
	struct frame *f;
	struct list_head *head, *pos, *nx;
	u32 n;

	n = tag % NFACTIVE;
	head = &d->factive[n];
	list_for_each_safe(pos, nx, head) {
		f = list_entry(pos, struct frame, head);
		if (f->tag == tag) {
			list_del(pos);
			return f;
		}
	}
	return NULL;
}

/*
 * Leave the top bit clear so we have tagspace for userland.
 * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
 * This driver reserves tag -1 to mean "unused frame."
 */
static int
newtag(struct aoedev *d)
{
	register ulong n;

	n = jiffies & 0xffff;
	return n |= (++d->lasttag & 0x7fff) << 16;
}

static u32
aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
{
	u32 host_tag = newtag(d);

	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
	memcpy(h->dst, t->addr, sizeof h->dst);
	h->type = __constant_cpu_to_be16(ETH_P_AOE);
	h->verfl = AOE_HVER;
	h->major = cpu_to_be16(d->aoemajor);
	h->minor = d->aoeminor;
	h->cmd = AOECMD_ATA;
	h->tag = cpu_to_be32(host_tag);

	return host_tag;
}

static inline void
put_lba(struct aoe_atahdr *ah, sector_t lba)
{
	ah->lba0 = lba;
	ah->lba1 = lba >>= 8;
	ah->lba2 = lba >>= 8;
	ah->lba3 = lba >>= 8;
	ah->lba4 = lba >>= 8;
	ah->lba5 = lba >>= 8;
}

static struct aoeif *
ifrotate(struct aoetgt *t)
{
	struct aoeif *ifp;

	ifp = t->ifp;
	ifp++;
	if (ifp >= &t->ifs[NAOEIFS] || ifp->nd == NULL)
		ifp = t->ifs;
	if (ifp->nd == NULL)
		return NULL;
	return t->ifp = ifp;
}

static void
skb_pool_put(struct aoedev *d, struct sk_buff *skb)
{
	__skb_queue_tail(&d->skbpool, skb);
}

static struct sk_buff *
skb_pool_get(struct aoedev *d)
{
	struct sk_buff *skb = skb_peek(&d->skbpool);

	if (skb && atomic_read(&skb_shinfo(skb)->dataref) == 1) {
		__skb_unlink(skb, &d->skbpool);
		return skb;
	}
	if (skb_queue_len(&d->skbpool) < NSKBPOOLMAX &&
	    (skb = new_skb(ETH_ZLEN)))
		return skb;

	return NULL;
}

void
aoe_freetframe(struct frame *f)
{
	struct aoetgt *t;

	t = f->t;
	f->buf = NULL;
	f->bv = NULL;
	f->r_skb = NULL;
	list_add(&f->head, &t->ffree);
}

static struct frame *
newtframe(struct aoedev *d, struct aoetgt *t)
{
	struct frame *f;
	struct sk_buff *skb;
	struct list_head *pos;

	if (list_empty(&t->ffree)) {
		if (t->falloc >= NSKBPOOLMAX*2)
			return NULL;
		f = kcalloc(1, sizeof(*f), GFP_ATOMIC);
		if (f == NULL)
			return NULL;
		t->falloc++;
		f->t = t;
	} else {
		pos = t->ffree.next;
		list_del(pos);
		f = list_entry(pos, struct frame, head);
	}

	skb = f->skb;
	if (skb == NULL) {
		f->skb = skb = new_skb(ETH_ZLEN);
		if (!skb)