fs: dlm: rework receive handling

	return !x;

}

#define DEFAULT_BUFFER_SIZE     4096

static bool dlm_check_buffer_size(unsigned int x)

{

	return (x < DEFAULT_BUFFER_SIZE);

#ifndef __CONFIG_DOT_H__

#define __CONFIG_DOT_H__

#define DEFAULT_BUFFER_SIZE     4096

struct dlm_config_node {

	int nodeid;

	int weight;

#define MAX_SEND_MSG_COUNT 25

#define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000)

struct cbuf {

	unsigned int base;

	unsigned int len;

	unsigned int mask;

};

static void cbuf_add(struct cbuf *cb, int n)

{

	cb->len += n;

}

static int cbuf_data(struct cbuf *cb)

{

	return ((cb->base + cb->len) & cb->mask);

}

static void cbuf_init(struct cbuf *cb, int size)

{

	cb->base = cb->len = 0;

	cb->mask = size-1;

}

static void cbuf_eat(struct cbuf *cb, int n)

{

	cb->len  -= n;

	cb->base += n;

	cb->base &= cb->mask;

}

static bool cbuf_empty(struct cbuf *cb)

{

	return cb->len == 0;

}

struct connection {

	struct socket *sock;	/* NULL if not connected */

	uint32_t nodeid;	/* So we know who we are in the list */

	int (*rx_action) (struct connection *);	/* What to do when active */

	void (*connect_action) (struct connection *);	/* What to do to connect */

	void (*shutdown_action)(struct connection *con); /* What to do to shutdown */

	struct page *rx_page;

	struct cbuf cb;

	int retries;

#define MAX_CONNECT_RETRIES 3

	struct hlist_node list;

	struct work_struct rwork; /* Receive workqueue */

	struct work_struct swork; /* Send workqueue */

	wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */

	unsigned char *rx_buf;

	int rx_buflen;

	int rx_leftover;

	struct rcu_head rcu;

};

#define sock2con(x) ((struct connection *)(x)->sk_user_data)

	if (!con)

		return NULL;

	con->rx_buflen = dlm_config.ci_buffer_size;

	con->rx_buf = kmalloc(con->rx_buflen, GFP_NOFS);

	if (!con->rx_buf) {

		kfree(con);

		return NULL;

	}

	con->nodeid = nodeid;

	mutex_init(&con->sock_mutex);

	INIT_LIST_HEAD(&con->writequeue);

		/* Will only re-enter once. */

		close_connection(con->othercon, false, true, true);

	}

	if (con->rx_page) {

		__free_page(con->rx_page);

		con->rx_page = NULL;

	}

	con->rx_leftover = 0;

	con->retries = 0;

	mutex_unlock(&con->sock_mutex);

	clear_bit(CF_CLOSING, &con->flags);

	shutdown_connection(con);

}

static int con_realloc_receive_buf(struct connection *con, int newlen)

{

	unsigned char *newbuf;

	newbuf = kmalloc(newlen, GFP_NOFS);

	if (!newbuf)

		return -ENOMEM;

	/* copy any leftover from last receive */

	if (con->rx_leftover)

		memmove(newbuf, con->rx_buf, con->rx_leftover);

	/* swap to new buffer space */

	kfree(con->rx_buf);

	con->rx_buflen = newlen;

	con->rx_buf = newbuf;

	return 0;

}

/* Data received from remote end */

static int receive_from_sock(struct connection *con)

{

	int ret = 0;

	struct msghdr msg = {};

	struct kvec iov[2];

	unsigned len;

	int r;

	int call_again_soon = 0;

	int nvec;

	struct msghdr msg;

	struct kvec iov;

	int ret, buflen;

	mutex_lock(&con->sock_mutex);

		ret = -EAGAIN;

		goto out_close;

	}

	if (con->nodeid == 0) {

		ret = -EINVAL;

		goto out_close;

	}

	if (con->rx_page == NULL) {

		/*

		 * This doesn't need to be atomic, but I think it should

		 * improve performance if it is.

		 */

		con->rx_page = alloc_page(GFP_ATOMIC);

		if (con->rx_page == NULL)

	/* realloc if we get new buffer size to read out */

	buflen = dlm_config.ci_buffer_size;

	if (con->rx_buflen != buflen && con->rx_leftover <= buflen) {

		ret = con_realloc_receive_buf(con, buflen);

		if (ret < 0)

			goto out_resched;

		cbuf_init(&con->cb, PAGE_SIZE);

	}

	/*

	 * iov[0] is the bit of the circular buffer between the current end

	 * point (cb.base + cb.len) and the end of the buffer.

	/* calculate new buffer parameter regarding last receive and

	 * possible leftover bytes

	 */

	iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);

	iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);

	iov[1].iov_len = 0;

	nvec = 1;

	iov.iov_base = con->rx_buf + con->rx_leftover;

	iov.iov_len = con->rx_buflen - con->rx_leftover;

	/*

	 * iov[1] is the bit of the circular buffer between the start of the

	 * buffer and the start of the currently used section (cb.base)

	 */

	if (cbuf_data(&con->cb) >= con->cb.base) {

		iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);

		iov[1].iov_len = con->cb.base;

		iov[1].iov_base = page_address(con->rx_page);

		nvec = 2;

	}

	len = iov[0].iov_len + iov[1].iov_len;

	iov_iter_kvec(&msg.msg_iter, READ, iov, nvec, len);

	r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);

	memset(&msg, 0, sizeof(msg));

	msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;

	ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,

			     msg.msg_flags);

	if (ret <= 0)

		goto out_close;

	else if (ret == len)

	else if (ret == iov.iov_len)

		call_again_soon = 1;

	cbuf_add(&con->cb, ret);

	ret = dlm_process_incoming_buffer(con->nodeid,

					  page_address(con->rx_page),

					  con->cb.base, con->cb.len,

					  PAGE_SIZE);

	if (ret < 0) {

		log_print("lowcomms err %d: addr=%p, base=%u, len=%u, read=%d",

			  ret, page_address(con->rx_page), con->cb.base,

			  con->cb.len, r);

		cbuf_eat(&con->cb, r);

	} else {

		cbuf_eat(&con->cb, ret);

	}

	/* new buflen according readed bytes and leftover from last receive */

	buflen = ret + con->rx_leftover;

	ret = dlm_process_incoming_buffer(con->nodeid, con->rx_buf, buflen);

	if (ret < 0)

		goto out_close;

	if (cbuf_empty(&con->cb) && !call_again_soon) {

		__free_page(con->rx_page);

		con->rx_page = NULL;

	/* calculate leftover bytes from process and put it into begin of

	 * the receive buffer, so next receive we have the full message

	 * at the start address of the receive buffer.

	 */

	con->rx_leftover = buflen - ret;

	if (con->rx_leftover) {

		memmove(con->rx_buf, con->rx_buf + ret,

			con->rx_leftover);

		call_again_soon = true;

	}

	if (call_again_soon)

		goto out_resched;

	mutex_unlock(&con->sock_mutex);

	return 0;

				result = -ENOMEM;

				goto accept_err;

			}

			othercon->rx_buflen = dlm_config.ci_buffer_size;

			othercon->rx_buf = kmalloc(othercon->rx_buflen, GFP_NOFS);

			if (!othercon->rx_buf) {

				mutex_unlock(&newcon->sock_mutex);

				kfree(othercon);

				log_print("failed to allocate incoming socket receive buffer");

				result = -ENOMEM;

				goto accept_err;

			}

			othercon->nodeid = nodeid;

			othercon->rx_action = receive_from_sock;

			mutex_init(&othercon->sock_mutex);

		con->shutdown_action(con);

}

static void connection_release(struct rcu_head *rcu)

{

	struct connection *con = container_of(rcu, struct connection, rcu);

	kfree(con->rx_buf);

	kfree(con);

}

static void free_conn(struct connection *con)

{

	close_connection(con, true, true, true);

	spin_unlock(&connections_lock);

	if (con->othercon) {

		clean_one_writequeue(con->othercon);

		kfree_rcu(con->othercon, rcu);

		call_rcu(&con->othercon->rcu, connection_release);

	}

	clean_one_writequeue(con);

	kfree_rcu(con, rcu);

	call_rcu(&con->rcu, connection_release);

}

static void work_flush(void)

 * into packets and sends them to the comms layer.

 */

#include <asm/unaligned.h>

#include "dlm_internal.h"

#include "lowcomms.h"

#include "config.h"

#include "lock.h"

#include "midcomms.h"

static void copy_from_cb(void *dst, const void *base, unsigned offset,

			 unsigned len, unsigned limit)

{

	unsigned copy = len;

	if ((copy + offset) > limit)

		copy = limit - offset;

	memcpy(dst, base + offset, copy);

	len -= copy;

	if (len)

		memcpy(dst + copy, base, len);

}

/*

 * Called from the low-level comms layer to process a buffer of

 * commands.

 *

 * Only complete messages are processed here, any "spare" bytes from

 * the end of a buffer are saved and tacked onto the front of the next

 * message that comes in. I doubt this will happen very often but we

 * need to be able to cope with it and I don't want the task to be waiting

 * for packets to come in when there is useful work to be done.

 */

int dlm_process_incoming_buffer(int nodeid, const void *base,

				unsigned offset, unsigned len, unsigned limit)

int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)

{

	union {

		unsigned char __buf[DLM_INBUF_LEN];

		/* this is to force proper alignment on some arches */

		union dlm_packet p;

	} __tmp;

	union dlm_packet *p = &__tmp.p;

	int ret = 0;

	int err = 0;

	const unsigned char *ptr = buf;

	const struct dlm_header *hd;

	uint16_t msglen;

	uint32_t lockspace;

	while (len > sizeof(struct dlm_header)) {

		/* Copy just the header to check the total length.  The

		   message may wrap around the end of the buffer back to the

		   start, so we need to use a temp buffer and copy_from_cb. */

		copy_from_cb(p, base, offset, sizeof(struct dlm_header),

			     limit);

	int ret = 0;

		msglen = le16_to_cpu(p->header.h_length);

		lockspace = p->header.h_lockspace;

	while (len >= sizeof(struct dlm_header)) {

		hd = (struct dlm_header *)ptr;

		err = -EINVAL;

		if (msglen < sizeof(struct dlm_header))

			break;

		if (p->header.h_cmd == DLM_MSG) {

			if (msglen < sizeof(struct dlm_message))

				break;

		} else {

			if (msglen < sizeof(struct dlm_rcom))

				break;

		}

		err = -E2BIG;

		if (msglen > dlm_config.ci_buffer_size) {

			log_print("message size %d from %d too big, buf len %d",

				  msglen, nodeid, len);

			break;

		/* no message should be more than this otherwise we

		 * cannot deliver this message to upper layers

		 */

		msglen = get_unaligned_le16(&hd->h_length);

		if (msglen > DEFAULT_BUFFER_SIZE) {

			log_print("received invalid length header: %u, will abort message parsing",

				  msglen);

			return -EBADMSG;

		}

		err = 0;

		/* If only part of the full message is contained in this

		   buffer, then do nothing and wait for lowcomms to call

		   us again later with more data.  We return 0 meaning

		   we've consumed none of the input buffer. */

		/* caller will take care that leftover

		 * will be parsed next call with more data

		 */

		if (msglen > len)

			break;

		/* Allocate a larger temp buffer if the full message won't fit

		   in the buffer on the stack (which should work for most

		   ordinary messages). */

		switch (hd->h_cmd) {

		case DLM_MSG:

			if (msglen < sizeof(struct dlm_message)) {

				log_print("dlm msg too small: %u, will skip this message",

					  msglen);

				goto skip;

			}

		if (msglen > sizeof(__tmp) && p == &__tmp.p) {

			p = kmalloc(dlm_config.ci_buffer_size, GFP_NOFS);

			if (p == NULL)

				return ret;

			break;

		case DLM_RCOM:

			if (msglen < sizeof(struct dlm_rcom)) {

				log_print("dlm rcom msg too small: %u, will skip this message",

					  msglen);

				goto skip;

			}

		copy_from_cb(p, base, offset, msglen, limit);

			break;

		default:

			log_print("unsupported h_cmd received: %u, will skip this message",

				  hd->h_cmd);

			goto skip;

		}

		BUG_ON(lockspace != p->header.h_lockspace);

		/* for aligned memory access, we just copy current message

		 * to begin of the buffer which contains already parsed buffer

		 * data and should provide align access for upper layers

		 * because the start address of the buffer has a aligned

		 * address. This memmove can be removed when the upperlayer

		 * is capable of unaligned memory access.

		 */

		memmove(buf, ptr, msglen);

		dlm_receive_buffer((union dlm_packet *)buf, nodeid);

skip:

		ret += msglen;

		offset += msglen;

		offset &= (limit - 1);

		len -= msglen;

		dlm_receive_buffer(p, nodeid);

		ptr += msglen;

	}

	if (p != &__tmp.p)

		kfree(p);

	return err ? err : ret;

	return ret;

}

#ifndef __MIDCOMMS_DOT_H__

#define __MIDCOMMS_DOT_H__

int dlm_process_incoming_buffer(int nodeid, const void *base, unsigned offset,

				unsigned len, unsigned limit);

int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int buflen);

#endif				/* __MIDCOMMS_DOT_H__ */