drivers/scsi/libfc/fc_libfc.c

   1 /*
   2  * Copyright(c) 2009 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  16  *
  17  * Maintained at www.Open-FCoE.org
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/types.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/crc32.h>
  24
  25 #include <scsi/libfc.h>
  26 #include <scsi/fc_encode.h>
  27
  28 #include "fc_libfc.h"
  29
  30 MODULE_AUTHOR("Open-FCoE.org");
  31 MODULE_DESCRIPTION("libfc");
  32 MODULE_LICENSE("GPL v2");
  33
  34 unsigned int fc_debug_logging;
  35 module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
  36 MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
  37
  38 /**
  39  * libfc_init() - Initialize libfc.ko
  40  */
  41 static int __init libfc_init(void)
  42 {
  43         int rc = 0;
  44
  45         rc = fc_setup_fcp();
  46         if (rc)
  47                 return rc;
  48
  49         rc = fc_setup_exch_mgr();
  50         if (rc)
  51                 goto destroy_pkt_cache;
  52
  53         rc = fc_setup_rport();
  54         if (rc)
  55                 goto destroy_em;
  56
  57         return rc;
  58 destroy_em:
  59         fc_destroy_exch_mgr();
  60 destroy_pkt_cache:
  61         fc_destroy_fcp();
  62         return rc;
  63 }
  64 module_init(libfc_init);
  65
  66 /**
  67  * libfc_exit() - Tear down libfc.ko
  68  */
  69 static void __exit libfc_exit(void)
  70 {
  71         fc_destroy_fcp();
  72         fc_destroy_exch_mgr();
  73         fc_destroy_rport();
  74 }
  75 module_exit(libfc_exit);
  76
  77 /**
  78  * fc_copy_buffer_to_sglist() - This routine copies the data of a buffer
  79  *                              into a scatter-gather list (SG list).
  80  *
  81  * @buf: pointer to the data buffer.
  82  * @len: the byte-length of the data buffer.
  83  * @sg: pointer to the pointer of the SG list.
  84  * @nents: pointer to the remaining number of entries in the SG list.
  85  * @offset: pointer to the current offset in the SG list.
  86  * @km_type: dedicated page table slot type for kmap_atomic.
  87  * @crc: pointer to the 32-bit crc value.
  88  *       If crc is NULL, CRC is not calculated.
  89  */
  90 u32 fc_copy_buffer_to_sglist(void *buf, size_t len,
  91                              struct scatterlist *sg,
  92                              u32 *nents, size_t *offset,
  93                              enum km_type km_type, u32 *crc)
  94 {
  95         size_t remaining = len;
  96         u32 copy_len = 0;
  97
  98         while (remaining > 0 && sg) {
  99                 size_t off, sg_bytes;
 100                 void *page_addr;
 101
 102                 if (*offset >= sg->length) {
 103                         /*
 104                          * Check for end and drop resources
 105                          * from the last iteration.
 106                          */
 107                         if (!(*nents))
 108                                 break;
 109                         --(*nents);
 110                         *offset -= sg->length;
 111                         sg = sg_next(sg);
 112                         continue;
 113                 }
 114                 sg_bytes = min(remaining, sg->length - *offset);
 115
 116                 /*
 117                  * The scatterlist item may be bigger than PAGE_SIZE,
 118                  * but we are limited to mapping PAGE_SIZE at a time.
 119                  */
 120                 off = *offset + sg->offset;
 121                 sg_bytes = min(sg_bytes,
 122                                (size_t)(PAGE_SIZE - (off & ~PAGE_MASK)));
 123                 page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT),
 124                                         km_type);
 125                 if (crc)
 126                         *crc = crc32(*crc, buf, sg_bytes);
 127                 memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes);
 128                 kunmap_atomic(page_addr, km_type);
 129                 buf += sg_bytes;
 130                 *offset += sg_bytes;
 131                 remaining -= sg_bytes;
 132                 copy_len += sg_bytes;
 133         }
 134         return copy_len;
 135 }
 136
 137 /**
 138  * fc_fill_hdr() -  fill FC header fields based on request
 139  * @fp: reply frame containing header to be filled in
 140  * @in_fp: request frame containing header to use in filling in reply
 141  * @r_ctl: R_CTL value for header
 142  * @f_ctl: F_CTL value for header, with 0 pad
 143  * @seq_cnt: sequence count for the header, ignored if frame has a sequence
 144  * @parm_offset: parameter / offset value
 145  */
 146 void fc_fill_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 147                  enum fc_rctl r_ctl, u32 f_ctl, u16 seq_cnt, u32 parm_offset)
 148 {
 149         struct fc_frame_header *fh;
 150         struct fc_frame_header *in_fh;
 151         struct fc_seq *sp;
 152         u32 fill;
 153
 154         fh = __fc_frame_header_get(fp);
 155         in_fh = __fc_frame_header_get(in_fp);
 156
 157         if (f_ctl & FC_FC_END_SEQ) {
 158                 fill = -fr_len(fp) & 3;
 159                 if (fill) {
 160                         /* TODO, this may be a problem with fragmented skb */
 161                         memset(skb_put(fp_skb(fp), fill), 0, fill);
 162                         f_ctl |= fill;
 163                 }
 164                 fr_eof(fp) = FC_EOF_T;
 165         } else {
 166                 WARN_ON(fr_len(fp) % 4 != 0);   /* no pad to non last frame */
 167                 fr_eof(fp) = FC_EOF_N;
 168         }
 169
 170         fh->fh_r_ctl = r_ctl;
 171         memcpy(fh->fh_d_id, in_fh->fh_s_id, sizeof(fh->fh_d_id));
 172         memcpy(fh->fh_s_id, in_fh->fh_d_id, sizeof(fh->fh_s_id));
 173         fh->fh_type = in_fh->fh_type;
 174         hton24(fh->fh_f_ctl, f_ctl);
 175         fh->fh_ox_id = in_fh->fh_ox_id;
 176         fh->fh_rx_id = in_fh->fh_rx_id;
 177         fh->fh_cs_ctl = 0;
 178         fh->fh_df_ctl = 0;
 179         fh->fh_parm_offset = htonl(parm_offset);
 180
 181         sp = fr_seq(in_fp);
 182         if (sp) {
 183                 fr_seq(fp) = sp;
 184                 fh->fh_seq_id = sp->id;
 185                 seq_cnt = sp->cnt;
 186         } else {
 187                 fh->fh_seq_id = 0;
 188         }
 189         fh->fh_seq_cnt = ntohs(seq_cnt);
 190         fr_sof(fp) = seq_cnt ? FC_SOF_N3 : FC_SOF_I3;
 191         fr_encaps(fp) = fr_encaps(in_fp);
 192 }
 193 EXPORT_SYMBOL(fc_fill_hdr);
 194
 195 /**
 196  * fc_fill_reply_hdr() -  fill FC reply header fields based on request
 197  * @fp: reply frame containing header to be filled in
 198  * @in_fp: request frame containing header to use in filling in reply
 199  * @r_ctl: R_CTL value for reply
 200  * @parm_offset: parameter / offset value
 201  */
 202 void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 203                        enum fc_rctl r_ctl, u32 parm_offset)
 204 {
 205         struct fc_seq *sp;
 206
 207         sp = fr_seq(in_fp);
 208         if (sp)
 209                 fr_seq(fp) = fr_dev(in_fp)->tt.seq_start_next(sp);
 210         fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
 211 }
 212 EXPORT_SYMBOL(fc_fill_reply_hdr);