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kernel/linux-rt-4.4.41/drivers/scsi/libfc/fc_frame.c 2.37 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright(c) 2007 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Maintained at www.Open-FCoE.org
   */
  
  /*
   * Frame allocation.
   */
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/skbuff.h>
  #include <linux/crc32.h>
  #include <linux/gfp.h>
  
  #include <scsi/fc_frame.h>
  
  /*
   * Check the CRC in a frame.
   */
  u32 fc_frame_crc_check(struct fc_frame *fp)
  {
  	u32 crc;
  	u32 error;
  	const u8 *bp;
  	unsigned int len;
  
  	WARN_ON(!fc_frame_is_linear(fp));
  	fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
  	len = (fr_len(fp) + 3) & ~3;	/* round up length to include fill */
  	bp = (const u8 *) fr_hdr(fp);
  	crc = ~crc32(~0, bp, len);
  	error = crc ^ fr_crc(fp);
  	return error;
  }
  EXPORT_SYMBOL(fc_frame_crc_check);
  
  /*
   * Allocate a frame intended to be sent.
   * Get an sk_buff for the frame and set the length.
   */
  struct fc_frame *_fc_frame_alloc(size_t len)
  {
  	struct fc_frame *fp;
  	struct sk_buff *skb;
  
  	WARN_ON((len % sizeof(u32)) != 0);
  	len += sizeof(struct fc_frame_header);
  	skb = alloc_skb_fclone(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM +
  			       NET_SKB_PAD, GFP_ATOMIC);
  	if (!skb)
  		return NULL;
  	skb_reserve(skb, NET_SKB_PAD + FC_FRAME_HEADROOM);
  	fp = (struct fc_frame *) skb;
  	fc_frame_init(fp);
  	skb_put(skb, len);
  	return fp;
  }
  EXPORT_SYMBOL(_fc_frame_alloc);
  
  struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len)
  {
  	struct fc_frame *fp;
  	size_t fill;
  
  	fill = payload_len % 4;
  	if (fill != 0)
  		fill = 4 - fill;
  	fp = _fc_frame_alloc(payload_len + fill);
  	if (fp) {
  		memset((char *) fr_hdr(fp) + payload_len, 0, fill);
  		/* trim is OK, we just allocated it so there are no fragments */
  		skb_trim(fp_skb(fp),
  			 payload_len + sizeof(struct fc_frame_header));
  	}
  	return fp;
  }
  EXPORT_SYMBOL(fc_frame_alloc_fill);