drivers/scsi/cxgb3i/cxgb3i_pdu.c

   1 /*
   2  * cxgb3i_pdu.c: Chelsio S3xx iSCSI driver.
   3  *
   4  * Copyright (c) 2008 Chelsio Communications, Inc.
   5  * Copyright (c) 2008 Mike Christie
   6  * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  *
  12  * Written by: Karen Xie (kxie@chelsio.com)
  13  */
  14
  15 #include <linux/skbuff.h>
  16 #include <linux/crypto.h>
  17 #include <scsi/scsi_cmnd.h>
  18 #include <scsi/scsi_host.h>
  19
  20 #include "cxgb3i.h"
  21 #include "cxgb3i_pdu.h"
  22
  23 #ifdef __DEBUG_CXGB3I_RX__
  24 #define cxgb3i_rx_debug         cxgb3i_log_debug
  25 #else
  26 #define cxgb3i_rx_debug(fmt...)
  27 #endif
  28
  29 #ifdef __DEBUG_CXGB3I_TX__
  30 #define cxgb3i_tx_debug         cxgb3i_log_debug
  31 #else
  32 #define cxgb3i_tx_debug(fmt...)
  33 #endif
  34
  35 static struct page *pad_page;
  36
  37 /*
  38  * pdu receive, interact with libiscsi_tcp
  39  */
  40 static inline int read_pdu_skb(struct iscsi_conn *conn, struct sk_buff *skb,
  41                                unsigned int offset, int offloaded)
  42 {
  43         int status = 0;
  44         int bytes_read;
  45
  46         bytes_read = iscsi_tcp_recv_skb(conn, skb, offset, offloaded, &status);
  47         switch (status) {
  48         case ISCSI_TCP_CONN_ERR:
  49                 return -EIO;
  50         case ISCSI_TCP_SUSPENDED:
  51                 /* no transfer - just have caller flush queue */
  52                 return bytes_read;
  53         case ISCSI_TCP_SKB_DONE:
  54                 /*
  55                  * pdus should always fit in the skb and we should get
  56                  * segment done notifcation.
  57                  */
  58                 iscsi_conn_printk(KERN_ERR, conn, "Invalid pdu or skb.");
  59                 return -EFAULT;
  60         case ISCSI_TCP_SEGMENT_DONE:
  61                 return bytes_read;
  62         default:
  63                 iscsi_conn_printk(KERN_ERR, conn, "Invalid iscsi_tcp_recv_skb "
  64                                   "status %d\n", status);
  65                 return -EINVAL;
  66         }
  67 }
  68
  69 static int cxgb3i_conn_read_pdu_skb(struct iscsi_conn *conn,
  70                                     struct sk_buff *skb)
  71 {
  72         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
  73         bool offloaded = 0;
  74         unsigned int offset;
  75         int rc;
  76
  77         cxgb3i_rx_debug("conn 0x%p, skb 0x%p, len %u, flag 0x%x.\n",
  78                         conn, skb, skb->len, skb_ulp_mode(skb));
  79
  80         if (!iscsi_tcp_recv_segment_is_hdr(tcp_conn)) {
  81                 iscsi_conn_failure(conn, ISCSI_ERR_PROTO);
  82                 return -EIO;
  83         }
  84
  85         if (conn->hdrdgst_en && (skb_ulp_mode(skb) & ULP2_FLAG_HCRC_ERROR)) {
  86                 iscsi_conn_failure(conn, ISCSI_ERR_HDR_DGST);
  87                 return -EIO;
  88         }
  89
  90         if (conn->datadgst_en && (skb_ulp_mode(skb) & ULP2_FLAG_DCRC_ERROR)) {
  91                 iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
  92                 return -EIO;
  93         }
  94
  95         /* iscsi hdr */
  96         rc = read_pdu_skb(conn, skb, 0, 0);
  97         if (rc <= 0)
  98                 return rc;
  99
 100         if (iscsi_tcp_recv_segment_is_hdr(tcp_conn))
 101                 return 0;
 102
 103         offset = rc;
 104         if (conn->hdrdgst_en)
 105                 offset += ISCSI_DIGEST_SIZE;
 106
 107         /* iscsi data */
 108         if (skb_ulp_mode(skb) & ULP2_FLAG_DATA_DDPED) {
 109                 cxgb3i_rx_debug("skb 0x%p, opcode 0x%x, data %u, ddp'ed, "
 110                                 "itt 0x%x.\n",
 111                                 skb,
 112                                 tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK,
 113                                 tcp_conn->in.datalen,
 114                                 ntohl(tcp_conn->in.hdr->itt));
 115                 offloaded = 1;
 116         } else {
 117                 cxgb3i_rx_debug("skb 0x%p, opcode 0x%x, data %u, NOT ddp'ed, "
 118                                 "itt 0x%x.\n",
 119                                 skb,
 120                                 tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK,
 121                                 tcp_conn->in.datalen,
 122                                 ntohl(tcp_conn->in.hdr->itt));
 123                 offset += sizeof(struct cpl_iscsi_hdr_norss);
 124         }
 125
 126         rc = read_pdu_skb(conn, skb, offset, offloaded);
 127         if (rc < 0)
 128                 return rc;
 129         else
 130                 return 0;
 131 }
 132
 133 /*
 134  * pdu transmit, interact with libiscsi_tcp
 135  */
 136 static inline void tx_skb_setmode(struct sk_buff *skb, int hcrc, int dcrc)
 137 {
 138         u8 submode = 0;
 139
 140         if (hcrc)
 141                 submode |= 1;
 142         if (dcrc)
 143                 submode |= 2;
 144         skb_ulp_mode(skb) = (ULP_MODE_ISCSI << 4) | submode;
 145 }
 146
 147 void cxgb3i_conn_cleanup_task(struct iscsi_task *task)
 148 {
 149         struct iscsi_tcp_task *tcp_task = task->dd_data;
 150
 151         /* never reached the xmit task callout */
 152         if (tcp_task->dd_data)
 153                 kfree_skb(tcp_task->dd_data);
 154         tcp_task->dd_data = NULL;
 155
 156         /* MNC - Do we need a check in case this is called but
 157          * cxgb3i_conn_alloc_pdu has never been called on the task */
 158         cxgb3i_release_itt(task, task->hdr_itt);
 159         iscsi_tcp_cleanup_task(task);
 160 }
 161
 162 /*
 163  * We do not support ahs yet
 164  */
 165 int cxgb3i_conn_alloc_pdu(struct iscsi_task *task, u8 opcode)
 166 {
 167         struct iscsi_tcp_task *tcp_task = task->dd_data;
 168         struct sk_buff *skb;
 169
 170         task->hdr = NULL;
 171         /* always allocate rooms for AHS */
 172         skb = alloc_skb(sizeof(struct iscsi_hdr) + ISCSI_MAX_AHS_SIZE +
 173                         TX_HEADER_LEN,  GFP_ATOMIC);
 174         if (!skb)
 175                 return -ENOMEM;
 176
 177         cxgb3i_tx_debug("task 0x%p, opcode 0x%x, skb 0x%p.\n",
 178                         task, opcode, skb);
 179
 180         tcp_task->dd_data = skb;
 181         skb_reserve(skb, TX_HEADER_LEN);
 182         task->hdr = (struct iscsi_hdr *)skb->data;
 183         task->hdr_max = sizeof(struct iscsi_hdr);
 184
 185         /* data_out uses scsi_cmd's itt */
 186         if (opcode != ISCSI_OP_SCSI_DATA_OUT)
 187                 cxgb3i_reserve_itt(task, &task->hdr->itt);
 188
 189         return 0;
 190 }
 191
 192 int cxgb3i_conn_init_pdu(struct iscsi_task *task, unsigned int offset,
 193                               unsigned int count)
 194 {
 195         struct iscsi_tcp_task *tcp_task = task->dd_data;
 196         struct sk_buff *skb = tcp_task->dd_data;
 197         struct iscsi_conn *conn = task->conn;
 198         struct page *pg;
 199         unsigned int datalen = count;
 200         int i, padlen = iscsi_padding(count);
 201         skb_frag_t *frag;
 202
 203         cxgb3i_tx_debug("task 0x%p,0x%p, offset %u, count %u, skb 0x%p.\n",
 204                         task, task->sc, offset, count, skb);
 205
 206         skb_put(skb, task->hdr_len);
 207         tx_skb_setmode(skb, conn->hdrdgst_en, datalen ? conn->datadgst_en : 0);
 208         if (!count)
 209                 return 0;
 210
 211         if (task->sc) {
 212                 struct scatterlist *sg;
 213                 struct scsi_data_buffer *sdb;
 214                 unsigned int sgoffset = offset;
 215                 struct page *sgpg;
 216                 unsigned int sglen;
 217
 218                 sdb = scsi_out(task->sc);
 219                 sg = sdb->table.sgl;
 220
 221                 for_each_sg(sdb->table.sgl, sg, sdb->table.nents, i) {
 222                         cxgb3i_tx_debug("sg %d, page 0x%p, len %u offset %u\n",
 223                                         i, sg_page(sg), sg->length, sg->offset);
 224
 225                         if (sgoffset < sg->length)
 226                                 break;
 227                         sgoffset -= sg->length;
 228                 }
 229                 sgpg = sg_page(sg);
 230                 sglen = sg->length - sgoffset;
 231
 232                 do {
 233                         int j = skb_shinfo(skb)->nr_frags;
 234                         unsigned int copy;
 235
 236                         if (!sglen) {
 237                                 sg = sg_next(sg);
 238                                 sgpg = sg_page(sg);
 239                                 sgoffset = 0;
 240                                 sglen = sg->length;
 241                                 ++i;
 242                         }
 243                         copy = min(sglen, datalen);
 244                         if (j && skb_can_coalesce(skb, j, sgpg,
 245                                                   sg->offset + sgoffset)) {
 246                                 skb_shinfo(skb)->frags[j - 1].size += copy;
 247                         } else {
 248                                 get_page(sgpg);
 249                                 skb_fill_page_desc(skb, j, sgpg,
 250                                                    sg->offset + sgoffset, copy);
 251                         }
 252                         sgoffset += copy;
 253                         sglen -= copy;
 254                         datalen -= copy;
 255                 } while (datalen);
 256         } else {
 257                 pg = virt_to_page(task->data);
 258
 259                 while (datalen) {
 260                         i = skb_shinfo(skb)->nr_frags;
 261                         frag = &skb_shinfo(skb)->frags[i];
 262
 263                         get_page(pg);
 264                         frag->page = pg;
 265                         frag->page_offset = 0;
 266                         frag->size = min((unsigned int)PAGE_SIZE, datalen);
 267
 268                         skb_shinfo(skb)->nr_frags++;
 269                         datalen -= frag->size;
 270                         pg++;
 271                 }
 272         }
 273
 274         if (padlen) {
 275                 i = skb_shinfo(skb)->nr_frags;
 276                 frag = &skb_shinfo(skb)->frags[i];
 277                 frag->page = pad_page;
 278                 frag->page_offset = 0;
 279                 frag->size = padlen;
 280                 skb_shinfo(skb)->nr_frags++;
 281         }
 282
 283         datalen = count + padlen;
 284         skb->data_len += datalen;
 285         skb->truesize += datalen;
 286         skb->len += datalen;
 287         return 0;
 288 }
 289
 290 int cxgb3i_conn_xmit_pdu(struct iscsi_task *task)
 291 {
 292         struct iscsi_tcp_task *tcp_task = task->dd_data;
 293         struct sk_buff *skb = tcp_task->dd_data;
 294         struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
 295         struct cxgb3i_conn *cconn = tcp_conn->dd_data;
 296         unsigned int datalen;
 297         int err;
 298
 299         if (!skb)
 300                 return 0;
 301
 302         datalen = skb->data_len;
 303         tcp_task->dd_data = NULL;
 304         err = cxgb3i_c3cn_send_pdus(cconn->cep->c3cn, skb);
 305         cxgb3i_tx_debug("task 0x%p, skb 0x%p, len %u/%u, rv %d.\n",
 306                         task, skb, skb->len, skb->data_len, err);
 307         if (err > 0) {
 308                 int pdulen = err;
 309
 310                 if (task->conn->hdrdgst_en)
 311                         pdulen += ISCSI_DIGEST_SIZE;
 312                 if (datalen && task->conn->datadgst_en)
 313                         pdulen += ISCSI_DIGEST_SIZE;
 314
 315                 task->conn->txdata_octets += pdulen;
 316                 return 0;
 317         }
 318
 319         if (err < 0 && err != -EAGAIN) {
 320                 kfree_skb(skb);
 321                 cxgb3i_tx_debug("itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n",
 322                                 task->itt, skb, skb->len, skb->data_len, err);
 323                 iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err);
 324                 iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED);
 325                 return err;
 326         }
 327         /* reset skb to send when we are called again */
 328         tcp_task->dd_data = skb;
 329         return -EAGAIN;
 330 }
 331
 332 int cxgb3i_pdu_init(void)
 333 {
 334         pad_page = alloc_page(GFP_KERNEL);
 335         if (!pad_page)
 336                 return -ENOMEM;
 337         memset(page_address(pad_page), 0, PAGE_SIZE);
 338         return 0;
 339 }
 340
 341 void cxgb3i_pdu_cleanup(void)
 342 {
 343         if (pad_page) {
 344                 __free_page(pad_page);
 345                 pad_page = NULL;
 346         }
 347 }
 348
 349 void cxgb3i_conn_pdu_ready(struct s3_conn *c3cn)
 350 {
 351         struct sk_buff *skb;
 352         unsigned int read = 0;
 353         struct iscsi_conn *conn = c3cn->user_data;
 354         int err = 0;
 355
 356         cxgb3i_rx_debug("cn 0x%p.\n", c3cn);
 357
 358         read_lock(&c3cn->callback_lock);
 359         if (unlikely(!conn || conn->suspend_rx)) {
 360                 cxgb3i_rx_debug("conn 0x%p, id %d, suspend_rx %lu!\n",
 361                                 conn, conn ? conn->id : 0xFF,
 362                                 conn ? conn->suspend_rx : 0xFF);
 363                 read_unlock(&c3cn->callback_lock);
 364                 return;
 365         }
 366         skb = skb_peek(&c3cn->receive_queue);
 367         while (!err && skb) {
 368                 __skb_unlink(skb, &c3cn->receive_queue);
 369                 read += skb_ulp_pdulen(skb);
 370                 err = cxgb3i_conn_read_pdu_skb(conn, skb);
 371                 __kfree_skb(skb);
 372                 skb = skb_peek(&c3cn->receive_queue);
 373         }
 374         read_unlock(&c3cn->callback_lock);
 375         if (c3cn) {
 376                 c3cn->copied_seq += read;
 377                 cxgb3i_c3cn_rx_credits(c3cn, read);
 378         }
 379         conn->rxdata_octets += read;
 380 }
 381
 382 void cxgb3i_conn_tx_open(struct s3_conn *c3cn)
 383 {
 384         struct iscsi_conn *conn = c3cn->user_data;
 385
 386         cxgb3i_tx_debug("cn 0x%p.\n", c3cn);
 387         if (conn) {
 388                 cxgb3i_tx_debug("cn 0x%p, cid %d.\n", c3cn, conn->id);
 389                 scsi_queue_work(conn->session->host, &conn->xmitwork);
 390         }
 391 }
 392
 393 void cxgb3i_conn_closing(struct s3_conn *c3cn)
 394 {
 395         struct iscsi_conn *conn;
 396
 397         read_lock(&c3cn->callback_lock);
 398         conn = c3cn->user_data;
 399         if (conn && c3cn->state != C3CN_STATE_ESTABLISHED)
 400                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 401         read_unlock(&c3cn->callback_lock);
 402 }