lustre/kernel_patches/patches/tcp-zero-copy.patch

   1 Index: linux-2.4.20/include/linux/skbuff.h
   2 ===================================================================
   3 --- linux-2.4.20.orig/include/linux/skbuff.h    2003-05-16 05:28:45.000000000 +0400
   4 +++ linux-2.4.20/include/linux/skbuff.h 2003-12-04 20:56:32.000000000 +0300
   5 @@ -116,6 +116,30 @@
   6         __u16 size;
   7  };
   8
   9 +/* Support for callback when skb data has been released */
  10 +typedef struct zccd                            /* Zero Copy Callback Descriptor */
  11 +{                                              /* (embed as first member of custom struct) */
  12 +       atomic_t        zccd_count;             /* reference count */
  13 +       void           (*zccd_destructor)(struct zccd *); /* callback when refcount reaches zero */
  14 +} zccd_t;
  15 +
  16 +static inline void zccd_init (zccd_t *d, void (*callback)(zccd_t *))
  17 +{
  18 +       atomic_set (&d->zccd_count, 1);
  19 +       d->zccd_destructor = callback;
  20 +}
  21 +
  22 +static inline void zccd_get (zccd_t *d)                /* take a reference */
  23 +{
  24 +       atomic_inc (&d->zccd_count);
  25 +}
  26 +
  27 +static inline void zccd_put (zccd_t *d)                /* release a reference */
  28 +{
  29 +       if (atomic_dec_and_test (&d->zccd_count))
  30 +               (d->zccd_destructor)(d);
  31 +}
  32 +
  33  /* This data is invariant across clones and lives at
  34   * the end of the header data, ie. at skb->end.
  35   */
  36 @@ -123,6 +147,12 @@
  37         atomic_t        dataref;
  38         unsigned int    nr_frags;
  39         struct sk_buff  *frag_list;
  40 +       zccd_t          *zccd;                  /* zero copy descriptor */
  41 +       zccd_t          *zccd2;                 /* 2nd zero copy descriptor */
  42 +       /* NB we expect zero-copy data to be at least 1 packet, so
  43 +        * having 2 zccds means we don't unneccessarily split the packet
  44 +        * where consecutive zero-copy sends abutt.
  45 +        */
  46         skb_frag_t      frags[MAX_SKB_FRAGS];
  47  };
  48
  49 Index: linux-2.4.20/include/net/tcp.h
  50 ===================================================================
  51 --- linux-2.4.20.orig/include/net/tcp.h 2003-05-16 05:29:15.000000000 +0400
  52 +++ linux-2.4.20/include/net/tcp.h      2003-12-04 20:56:32.000000000 +0300
  53 @@ -638,6 +638,8 @@
  54
  55  extern int                     tcp_sendmsg(struct sock *sk, struct msghdr *msg, int size);
  56  extern ssize_t                 tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
  57 +extern ssize_t                 tcp_sendpage_zccd(struct socket *sock, struct page *page, int offset, size_t size,
  58 +                                                 int flags, zccd_t *zccd);
  59
  60  extern int                     tcp_ioctl(struct sock *sk,
  61                                           int cmd,
  62 @@ -731,6 +733,9 @@
  63                                             struct msghdr *msg,
  64                                             int len, int nonblock,
  65                                             int flags, int *addr_len);
  66 +extern int                     tcp_recvpackets(struct sock *sk,
  67 +                                               struct sk_buff_head *packets,
  68 +                                               int len, int nonblock);
  69
  70  extern int                     tcp_listen_start(struct sock *sk);
  71
  72 Index: linux-2.4.20/net/netsyms.c
  73 ===================================================================
  74 --- linux-2.4.20.orig/net/netsyms.c     2003-05-16 05:29:15.000000000 +0400
  75 +++ linux-2.4.20/net/netsyms.c  2003-12-04 20:56:44.000000000 +0300
  76 @@ -408,6 +408,8 @@
  77
  78  #endif
  79
  80 +EXPORT_SYMBOL(tcp_sendpage_zccd);
  81 +EXPORT_SYMBOL(tcp_recvpackets);
  82  EXPORT_SYMBOL(tcp_read_sock);
  83
  84  EXPORT_SYMBOL(netlink_set_err);
  85 Index: linux-2.4.20/net/core/skbuff.c
  86 ===================================================================
  87 --- linux-2.4.20.orig/net/core/skbuff.c 2003-05-16 05:28:46.000000000 +0400
  88 +++ linux-2.4.20/net/core/skbuff.c      2003-12-04 20:56:32.000000000 +0300
  89 @@ -208,6 +208,8 @@
  90         atomic_set(&(skb_shinfo(skb)->dataref), 1);
  91         skb_shinfo(skb)->nr_frags = 0;
  92         skb_shinfo(skb)->frag_list = NULL;
  93 +       skb_shinfo(skb)->zccd = NULL;           /* skbuffs kick off with NO user zero copy descriptors */
  94 +       skb_shinfo(skb)->zccd2 = NULL;
  95         return skb;
  96
  97  nodata:
  98 @@ -276,6 +278,10 @@
  99  {
 100         if (!skb->cloned ||
 101             atomic_dec_and_test(&(skb_shinfo(skb)->dataref))) {
 102 +               if (skb_shinfo(skb)->zccd != NULL) /* zero copy callback descriptor? */
 103 +                       zccd_put (skb_shinfo(skb)->zccd); /* release hold */
 104 +               if (skb_shinfo(skb)->zccd2 != NULL) /* 2nd zero copy callback descriptor? */
 105 +                       zccd_put (skb_shinfo(skb)->zccd2); /* release hold */
 106                 if (skb_shinfo(skb)->nr_frags) {
 107                         int i;
 108                         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 109 @@ -532,6 +538,8 @@
 110         atomic_set(&(skb_shinfo(skb)->dataref), 1);
 111         skb_shinfo(skb)->nr_frags = 0;
 112         skb_shinfo(skb)->frag_list = NULL;
 113 +       skb_shinfo(skb)->zccd = NULL;           /* copied data => no user zero copy descriptor */
 114 +       skb_shinfo(skb)->zccd2 = NULL;
 115
 116         /* We are no longer a clone, even if we were. */
 117         skb->cloned = 0;
 118 @@ -578,6 +586,14 @@
 119         n->data_len = skb->data_len;
 120         n->len = skb->len;
 121
 122 +       if (skb_shinfo(skb)->zccd != NULL)      /* user zero copy descriptor? */
 123 +               zccd_get (skb_shinfo(skb)->zccd); /* 1 more ref (pages are shared) */
 124 +       skb_shinfo(n)->zccd = skb_shinfo(skb)->zccd;
 125 +
 126 +       if (skb_shinfo(skb)->zccd2 != NULL)     /* 2nd user zero copy descriptor? */
 127 +               zccd_get (skb_shinfo(skb)->zccd2); /* 1 more ref (pages are shared) */
 128 +       skb_shinfo(n)->zccd2 = skb_shinfo(skb)->zccd2;
 129 +
 130         if (skb_shinfo(skb)->nr_frags) {
 131                 int i;
 132
 133 @@ -620,6 +636,8 @@
 134         u8 *data;
 135         int size = nhead + (skb->end - skb->head) + ntail;
 136         long off;
 137 +       zccd_t *zccd = skb_shinfo(skb)->zccd;   /* stash user zero copy descriptor */
 138 +       zccd_t *zccd2 = skb_shinfo(skb)->zccd2; /* stash 2nd user zero copy descriptor */
 139
 140         if (skb_shared(skb))
 141                 BUG();
 142 @@ -641,6 +659,11 @@
 143         if (skb_shinfo(skb)->frag_list)
 144                 skb_clone_fraglist(skb);
 145
 146 +       if (zccd != NULL)                       /* user zero copy descriptor? */
 147 +               zccd_get (zccd);                /* extra ref (pages are shared) */
 148 +       if (zccd2 != NULL)                      /* 2nd user zero copy descriptor? */
 149 +               zccd_get (zccd2);               /* extra ref (pages are shared) */
 150 +
 151         skb_release_data(skb);
 152
 153         off = (data+nhead) - skb->head;
 154 @@ -655,6 +678,8 @@
 155         skb->nh.raw += off;
 156         skb->cloned = 0;
 157         atomic_set(&skb_shinfo(skb)->dataref, 1);
 158 +       skb_shinfo(skb)->zccd = zccd;
 159 +       skb_shinfo(skb)->zccd2 = zccd2;
 160         return 0;
 161
 162  nodata:
 163 Index: linux-2.4.20/net/ipv4/tcp.c
 164 ===================================================================
 165 --- linux-2.4.20.orig/net/ipv4/tcp.c    2003-05-16 05:29:15.000000000 +0400
 166 +++ linux-2.4.20/net/ipv4/tcp.c 2003-12-04 20:56:32.000000000 +0300
 167 @@ -745,7 +745,7 @@
 168         goto out;
 169  }
 170
 171 -ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, size_t psize, int flags);
 172 +ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, size_t psize, int flags, zccd_t *zccd);
 173
 174  static inline int
 175  can_coalesce(struct sk_buff *skb, int i, struct page *page, int off)
 176 @@ -824,7 +824,8 @@
 177         return err;
 178  }
 179
 180 -ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, size_t psize, int flags)
 181 +/* Extra parameter: user zero copy descriptor (or NULL if not doing that) */
 182 +ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, size_t psize, int flags, zccd_t *zccd)
 183  {
 184         struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
 185         int mss_now;
 186 @@ -872,6 +873,17 @@
 187                         copy = size;
 188
 189                 i = skb_shinfo(skb)->nr_frags;
 190 +
 191 +               if (zccd != NULL &&             /* this is a zcc I/O */
 192 +                   skb_shinfo(skb)->zccd != NULL && /* skb is part of a zcc I/O */
 193 +                   skb_shinfo(skb)->zccd2 != NULL &&
 194 +                   skb_shinfo(skb)->zccd != zccd && /* not the same one */
 195 +                   skb_shinfo(skb)->zccd2 != zccd)
 196 +               {
 197 +                       tcp_mark_push (tp, skb);
 198 +                       goto new_segment;
 199 +               }
 200 +
 201                 if (can_coalesce(skb, i, page, offset)) {
 202                         skb_shinfo(skb)->frags[i-1].size += copy;
 203                 } else if (i < MAX_SKB_FRAGS) {
 204 @@ -882,6 +894,20 @@
 205                         goto new_segment;
 206                 }
 207
 208 +               if (zccd != NULL &&     /* this is a zcc I/O */
 209 +                   skb_shinfo(skb)->zccd != zccd && /* not already referencing this zccd */
 210 +                   skb_shinfo(skb)->zccd2 != zccd)
 211 +               {
 212 +                       zccd_get (zccd);        /* bump ref count */
 213 +
 214 +                       BUG_TRAP (skb_shinfo(skb)->zccd2 == NULL);
 215 +
 216 +                       if (skb_shinfo(skb)->zccd == NULL) /* reference this zccd */
 217 +                               skb_shinfo(skb)->zccd = zccd;
 218 +                       else
 219 +                               skb_shinfo(skb)->zccd2 = zccd;
 220 +               }
 221 +
 222                 skb->len += copy;
 223                 skb->data_len += copy;
 224                 skb->ip_summed = CHECKSUM_HW;
 225 @@ -945,7 +971,31 @@
 226
 227         lock_sock(sk);
 228         TCP_CHECK_TIMER(sk);
 229 -       res = do_tcp_sendpages(sk, &page, offset, size, flags);
 230 +       res = do_tcp_sendpages(sk, &page, offset, size, flags, NULL);
 231 +       TCP_CHECK_TIMER(sk);
 232 +       release_sock(sk);
 233 +       return res;
 234 +}
 235 +
 236 +ssize_t tcp_sendpage_zccd(struct socket *sock, struct page *page, int offset, size_t size,
 237 +                         int flags, zccd_t *zccd)
 238 +{
 239 +       ssize_t res;
 240 +       struct sock *sk = sock->sk;
 241 +
 242 +#define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)
 243 +
 244 +       if (!(sk->route_caps & NETIF_F_SG) ||   /* caller shouldn't waste her time */
 245 +           !(sk->route_caps & TCP_ZC_CSUM_FLAGS)) /* on double mapping */
 246 +               BUG ();
 247 +
 248 +#undef TCP_ZC_CSUM_FLAGS
 249 +
 250 +       lock_sock(sk);
 251 +       TCP_CHECK_TIMER(sk);
 252 +
 253 +       res = do_tcp_sendpages(sk, &page, offset, size, flags, zccd);
 254 +
 255         TCP_CHECK_TIMER(sk);
 256         release_sock(sk);
 257         return res;
 258 @@ -1769,6 +1819,202 @@
 259         goto out;
 260  }
 261
 262 +int tcp_recvpackets (struct sock *sk, struct sk_buff_head *packets,
 263 +                    int len, int nonblock)
 264 +{
 265 +       struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
 266 +       int copied;
 267 +       long timeo;
 268 +
 269 +       BUG_TRAP (len > 0);
 270 +       /*BUG_TRAP ((flags & (MSG_OOB | MSG_PEEK | MSG_TRUNC)) == 0);*/
 271 +
 272 +       lock_sock(sk);
 273 +
 274 +       TCP_CHECK_TIMER(sk);
 275 +
 276 +       copied = -ENOTCONN;
 277 +       if (sk->state == TCP_LISTEN)
 278 +               goto out;
 279 +
 280 +       copied = 0;
 281 +       timeo = sock_rcvtimeo(sk, nonblock);
 282 +
 283 +       do {
 284 +               struct sk_buff * skb;
 285 +               u32 offset;
 286 +               unsigned long used;
 287 +               int exhausted;
 288 +               int eaten;
 289 +
 290 +               /* Are we at urgent data? Stop if we have read anything. */
 291 +               if (copied && tp->urg_data && tp->urg_seq == tp->copied_seq)
 292 +                       break;
 293 +
 294 +               /* We need to check signals first, to get correct SIGURG
 295 +                * handling. FIXME: Need to check this doesnt impact 1003.1g
 296 +                * and move it down to the bottom of the loop
 297 +                */
 298 +               if (signal_pending(current)) {
 299 +                       if (copied)
 300 +                               break;
 301 +                       copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
 302 +                       break;
 303 +               }
 304 +
 305 +               /* Next get a buffer. */
 306 +
 307 +               skb = skb_peek(&sk->receive_queue);
 308 +
 309 +               if (skb == NULL)                /* nothing ready */
 310 +               {
 311 +                       if (copied) {
 312 +                               if (sk->err ||
 313 +                                   sk->state == TCP_CLOSE ||
 314 +                                   (sk->shutdown & RCV_SHUTDOWN) ||
 315 +                                   !timeo ||
 316 +                                   (0))
 317 +                                       break;
 318 +                       } else {
 319 +                               if (sk->done)
 320 +                                       break;
 321 +
 322 +                               if (sk->err) {
 323 +                                       copied = sock_error(sk);
 324 +                                       break;
 325 +                               }
 326 +
 327 +                               if (sk->shutdown & RCV_SHUTDOWN)
 328 +                                       break;
 329 +
 330 +                               if (sk->state == TCP_CLOSE) {
 331 +                                       if (!sk->done) {
 332 +                                               /* This occurs when user tries to read
 333 +                                                * from never connected socket.
 334 +                                                */
 335 +                                               copied = -ENOTCONN;
 336 +                                               break;
 337 +                                       }
 338 +                                       break;
 339 +                               }
 340 +
 341 +                               if (!timeo) {
 342 +                                       copied = -EAGAIN;
 343 +                                       break;
 344 +                               }
 345 +                       }
 346 +
 347 +                       cleanup_rbuf(sk, copied);
 348 +                       timeo = tcp_data_wait(sk, timeo);
 349 +                       continue;
 350 +               }
 351 +
 352 +               BUG_TRAP (atomic_read (&skb->users) == 1);
 353 +
 354 +               exhausted = eaten = 0;
 355 +
 356 +               offset = tp->copied_seq - TCP_SKB_CB(skb)->seq;
 357 +               if (skb->h.th->syn)
 358 +                       offset--;
 359 +
 360 +               used = skb->len - offset;
 361 +
 362 +               if (tp->urg_data) {
 363 +                       u32 urg_offset = tp->urg_seq - tp->copied_seq;
 364 +                       if (urg_offset < used) {
 365 +                               if (!urg_offset) { /* at urgent date */
 366 +                                       if (!sk->urginline) {
 367 +                                               tp->copied_seq++; /* discard the single byte of urgent data */
 368 +                                               offset++;
 369 +                                               used--;
 370 +                                       }
 371 +                               } else          /* truncate read */
 372 +                                       used = urg_offset;
 373 +                       }
 374 +               }
 375 +
 376 +               BUG_TRAP (used >= 0);
 377 +               if (len < used)
 378 +                       used = len;
 379 +
 380 +               if (used == 0)
 381 +                       exhausted = 1;
 382 +               else
 383 +               {
 384 +                       if (skb_is_nonlinear (skb))
 385 +                       {
 386 +                               int   rc = skb_linearize (skb, GFP_KERNEL);
 387 +
 388 +                               printk ("tcp_recvpackets(): linearising: %d\n", rc);
 389 +
 390 +                               if (rc)
 391 +                               {
 392 +                                       if (!copied)
 393 +                                               copied = rc;
 394 +                                       break;
 395 +                               }
 396 +                       }
 397 +
 398 +                       if ((offset + used) == skb->len) /* consuming the whole packet */
 399 +                       {
 400 +                               __skb_unlink (skb, &sk->receive_queue);
 401 +                               dst_release (skb->dst);
 402 +                               skb_orphan (skb);
 403 +                               __skb_pull (skb, offset);
 404 +                               __skb_queue_tail (packets, skb);
 405 +                               exhausted = eaten = 1;
 406 +                       }
 407 +                       else                    /* consuming only part of the packet */
 408 +                       {
 409 +                               struct sk_buff *skb2 = skb_clone (skb, GFP_KERNEL);
 410 +
 411 +                               if (skb2 == NULL)
 412 +                               {
 413 +                                       if (!copied)
 414 +                                               copied = -ENOMEM;
 415 +                                       break;
 416 +                               }
 417 +
 418 +                               dst_release (skb2->dst);
 419 +                               __skb_pull (skb2, offset);
 420 +                               __skb_trim (skb2, used);
 421 +                               __skb_queue_tail (packets, skb2);
 422 +                       }
 423 +
 424 +                       tp->copied_seq += used;
 425 +                       copied += used;
 426 +                       len -= used;
 427 +               }
 428 +
 429 +               if (tp->urg_data && after(tp->copied_seq,tp->urg_seq)) {
 430 +                       tp->urg_data = 0;
 431 +                       tcp_fast_path_check(sk, tp);
 432 +               }
 433 +
 434 +               if (!exhausted)
 435 +                       continue;
 436 +
 437 +               if (skb->h.th->fin)
 438 +               {
 439 +                       tp->copied_seq++;
 440 +                       if (!eaten)
 441 +                               tcp_eat_skb (sk, skb);
 442 +                       break;
 443 +               }
 444 +
 445 +               if (!eaten)
 446 +                       tcp_eat_skb (sk, skb);
 447 +
 448 +       } while (len > 0);
 449 +
 450 + out:
 451 +       /* Clean up data we have read: This will do ACK frames. */
 452 +       cleanup_rbuf(sk, copied);
 453 +       TCP_CHECK_TIMER(sk);
 454 +       release_sock(sk);
 455 +       return copied;
 456 +}
 457 +
 458  /*
 459   *     State processing on a close. This implements the state shift for
 460   *     sending our FIN frame. Note that we only send a FIN for some