/*
   * Copyright (c) 2006 Oracle.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  #include <linux/kernel.h>

  #include <linux/slab.h>

  #include <linux/export.h>

  
  #include "rds.h"

  static unsigned int	rds_exthdr_size[__RDS_EXTHDR_MAX] = {
  [RDS_EXTHDR_NONE]	= 0,
  [RDS_EXTHDR_VERSION]	= sizeof(struct rds_ext_header_version),
  [RDS_EXTHDR_RDMA]	= sizeof(struct rds_ext_header_rdma),
  [RDS_EXTHDR_RDMA_DEST]	= sizeof(struct rds_ext_header_rdma_dest),
  };
  
  
  void rds_message_addref(struct rds_message *rm)
  {
  	rdsdebug("addref rm %p ref %d
  ", rm, atomic_read(&rm->m_refcount));
  	atomic_inc(&rm->m_refcount);
  }

  EXPORT_SYMBOL_GPL(rds_message_addref);

  
  /*
   * This relies on dma_map_sg() not touching sg[].page during merging.
   */
  static void rds_message_purge(struct rds_message *rm)
  {
  	unsigned long i;
  
  	if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
  		return;

  	for (i = 0; i < rm->data.op_nents; i++) {
  		rdsdebug("putting data page %p
  ", (void *)sg_page(&rm->data.op_sg[i]));

  		/* XXX will have to put_page for page refs */

  		__free_page(sg_page(&rm->data.op_sg[i]));

  	}

  	rm->data.op_nents = 0;

  	if (rm->rdma.op_active)
  		rds_rdma_free_op(&rm->rdma);
  	if (rm->rdma.op_rdma_mr)
  		rds_mr_put(rm->rdma.op_rdma_mr);

  
  	if (rm->atomic.op_active)
  		rds_atomic_free_op(&rm->atomic);
  	if (rm->atomic.op_rdma_mr)
  		rds_mr_put(rm->atomic.op_rdma_mr);

  }

  
  void rds_message_put(struct rds_message *rm)
  {
  	rdsdebug("put rm %p ref %d
  ", rm, atomic_read(&rm->m_refcount));

  	if (atomic_read(&rm->m_refcount) == 0) {
  printk(KERN_CRIT "danger refcount zero on %p
  ", rm);
  WARN_ON(1);
  	}

  	if (atomic_dec_and_test(&rm->m_refcount)) {
  		BUG_ON(!list_empty(&rm->m_sock_item));
  		BUG_ON(!list_empty(&rm->m_conn_item));
  		rds_message_purge(rm);
  
  		kfree(rm);
  	}
  }

  EXPORT_SYMBOL_GPL(rds_message_put);

  void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
  				 __be16 dport, u64 seq)
  {
  	hdr->h_flags = 0;
  	hdr->h_sport = sport;
  	hdr->h_dport = dport;
  	hdr->h_sequence = cpu_to_be64(seq);
  	hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
  }

  EXPORT_SYMBOL_GPL(rds_message_populate_header);

  int rds_message_add_extension(struct rds_header *hdr, unsigned int type,
  			      const void *data, unsigned int len)

  {
  	unsigned int ext_len = sizeof(u8) + len;
  	unsigned char *dst;
  
  	/* For now, refuse to add more than one extension header */
  	if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
  		return 0;

  	if (type >= __RDS_EXTHDR_MAX || len != rds_exthdr_size[type])

  		return 0;
  
  	if (ext_len >= RDS_HEADER_EXT_SPACE)
  		return 0;
  	dst = hdr->h_exthdr;
  
  	*dst++ = type;
  	memcpy(dst, data, len);
  
  	dst[len] = RDS_EXTHDR_NONE;
  	return 1;
  }

  EXPORT_SYMBOL_GPL(rds_message_add_extension);

  
  /*
   * If a message has extension headers, retrieve them here.
   * Call like this:
   *
   * unsigned int pos = 0;
   *
   * while (1) {
   *	buflen = sizeof(buffer);
   *	type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
   *	if (type == RDS_EXTHDR_NONE)
   *		break;
   *	...
   * }
   */
  int rds_message_next_extension(struct rds_header *hdr,
  		unsigned int *pos, void *buf, unsigned int *buflen)
  {
  	unsigned int offset, ext_type, ext_len;
  	u8 *src = hdr->h_exthdr;
  
  	offset = *pos;
  	if (offset >= RDS_HEADER_EXT_SPACE)
  		goto none;
  
  	/* Get the extension type and length. For now, the
  	 * length is implied by the extension type. */
  	ext_type = src[offset++];
  
  	if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
  		goto none;
  	ext_len = rds_exthdr_size[ext_type];
  	if (offset + ext_len > RDS_HEADER_EXT_SPACE)
  		goto none;
  
  	*pos = offset + ext_len;
  	if (ext_len < *buflen)
  		*buflen = ext_len;
  	memcpy(buf, src + offset, *buflen);
  	return ext_type;
  
  none:
  	*pos = RDS_HEADER_EXT_SPACE;
  	*buflen = 0;
  	return RDS_EXTHDR_NONE;
  }

  int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
  {
  	struct rds_ext_header_rdma_dest ext_hdr;
  
  	ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
  	ext_hdr.h_rdma_offset = cpu_to_be32(offset);
  	return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
  }

  EXPORT_SYMBOL_GPL(rds_message_add_rdma_dest_extension);

  /*
   * Each rds_message is allocated with extra space for the scatterlist entries
   * rds ops will need. This is to minimize memory allocation count. Then, each rds op
   * can grab SGs when initializing its part of the rds_message.
   */
  struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)

  {
  	struct rds_message *rm;

  	rm = kzalloc(sizeof(struct rds_message) + extra_len, gfp);

  	if (!rm)
  		goto out;

  	rm->m_used_sgs = 0;
  	rm->m_total_sgs = extra_len / sizeof(struct scatterlist);

  	atomic_set(&rm->m_refcount, 1);
  	INIT_LIST_HEAD(&rm->m_sock_item);
  	INIT_LIST_HEAD(&rm->m_conn_item);
  	spin_lock_init(&rm->m_rs_lock);

  	init_waitqueue_head(&rm->m_flush_wait);

  
  out:
  	return rm;
  }

  /*
   * RDS ops use this to grab SG entries from the rm's sg pool.
   */
  struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
  {
  	struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
  	struct scatterlist *sg_ret;
  
  	WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);

  	WARN_ON(!nents);

  	if (rm->m_used_sgs + nents > rm->m_total_sgs)
  		return NULL;

  	sg_ret = &sg_first[rm->m_used_sgs];

  	sg_init_table(sg_ret, nents);

  	rm->m_used_sgs += nents;
  
  	return sg_ret;
  }

  struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
  {
  	struct rds_message *rm;
  	unsigned int i;

  	int num_sgs = ceil(total_len, PAGE_SIZE);
  	int extra_bytes = num_sgs * sizeof(struct scatterlist);

  	rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);

  	if (!rm)

  		return ERR_PTR(-ENOMEM);
  
  	set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
  	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);

  	rm->data.op_nents = ceil(total_len, PAGE_SIZE);
  	rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);

  	if (!rm->data.op_sg) {
  		rds_message_put(rm);

  		return ERR_PTR(-ENOMEM);

  	}

  	for (i = 0; i < rm->data.op_nents; ++i) {
  		sg_set_page(&rm->data.op_sg[i],

  				virt_to_page(page_addrs[i]),
  				PAGE_SIZE, 0);
  	}
  
  	return rm;
  }

  int rds_message_copy_from_user(struct rds_message *rm, struct iovec *first_iov,

  					       size_t total_len)
  {
  	unsigned long to_copy;
  	unsigned long iov_off;
  	unsigned long sg_off;

  	struct iovec *iov;
  	struct scatterlist *sg;

  	int ret = 0;

  
  	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
  
  	/*
  	 * now allocate and copy in the data payload.
  	 */

  	sg = rm->data.op_sg;

  	iov = first_iov;
  	iov_off = 0;
  	sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */
  
  	while (total_len) {

  		if (!sg_page(sg)) {

  			ret = rds_page_remainder_alloc(sg, total_len,
  						       GFP_HIGHUSER);
  			if (ret)
  				goto out;

  			rm->data.op_nents++;

  			sg_off = 0;
  		}
  
  		while (iov_off == iov->iov_len) {
  			iov_off = 0;
  			iov++;
  		}
  
  		to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
  		to_copy = min_t(size_t, to_copy, total_len);
  
  		rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
  			 "sg [%p, %u, %u] + %lu
  ",
  			 to_copy, iov->iov_base, iov->iov_len, iov_off,
  			 (void *)sg_page(sg), sg->offset, sg->length, sg_off);
  
  		ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
  					      iov->iov_base + iov_off,
  					      to_copy);
  		if (ret)
  			goto out;
  
  		iov_off += to_copy;
  		total_len -= to_copy;
  		sg_off += to_copy;
  
  		if (sg_off == sg->length)
  			sg++;
  	}

  out:

  	return ret;

  }
  
  int rds_message_inc_copy_to_user(struct rds_incoming *inc,
  				 struct iovec *first_iov, size_t size)
  {
  	struct rds_message *rm;
  	struct iovec *iov;
  	struct scatterlist *sg;
  	unsigned long to_copy;
  	unsigned long iov_off;
  	unsigned long vec_off;
  	int copied;
  	int ret;
  	u32 len;
  
  	rm = container_of(inc, struct rds_message, m_inc);
  	len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
  
  	iov = first_iov;
  	iov_off = 0;

  	sg = rm->data.op_sg;

  	vec_off = 0;
  	copied = 0;
  
  	while (copied < size && copied < len) {
  		while (iov_off == iov->iov_len) {
  			iov_off = 0;
  			iov++;
  		}
  
  		to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
  		to_copy = min_t(size_t, to_copy, size - copied);
  		to_copy = min_t(unsigned long, to_copy, len - copied);
  
  		rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
  			 "sg [%p, %u, %u] + %lu
  ",
  			 to_copy, iov->iov_base, iov->iov_len, iov_off,
  			 sg_page(sg), sg->offset, sg->length, vec_off);
  
  		ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
  					    iov->iov_base + iov_off,
  					    to_copy);
  		if (ret) {
  			copied = ret;
  			break;
  		}
  
  		iov_off += to_copy;
  		vec_off += to_copy;
  		copied += to_copy;
  
  		if (vec_off == sg->length) {
  			vec_off = 0;
  			sg++;
  		}
  	}
  
  	return copied;
  }
  
  /*
   * If the message is still on the send queue, wait until the transport
   * is done with it. This is particularly important for RDMA operations.
   */
  void rds_message_wait(struct rds_message *rm)
  {

  	wait_event_interruptible(rm->m_flush_wait,

  			!test_bit(RDS_MSG_MAPPED, &rm->m_flags));
  }
  
  void rds_message_unmapped(struct rds_message *rm)
  {
  	clear_bit(RDS_MSG_MAPPED, &rm->m_flags);

  	wake_up_interruptible(&rm->m_flush_wait);

  }

  EXPORT_SYMBOL_GPL(rds_message_unmapped);