src/patches/suse-2.6.27.31/patches.arch/s390-11-05-qdio_error_reporting_hs.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: qdio: fix hipersocket busy error handling
   3 References: bnc#484767,LTC#52204
   4
   5 Symptom:     Lower performance of hipersocket connections in case of
   6              busy errors.
   7 Problem:     The immediate retry for a busy condition is missing and the
   8              qeth notification about a failed send operation may indicate
   9              a wrong buffer position since a temporary SIGA error is not
  10              reported immediately.
  11 Solution:    Retry immediately after a busy condition and report SIGA errors
  12              directly to qeth.
  13
  14 Acked-by: John Jolly <jjolly@suse.de>
  15 ---
  16  drivers/s390/cio/qdio.h      |    7 -
  17  drivers/s390/cio/qdio_main.c |  181 ++++++++++++++-----------------------------
  18  2 files changed, 63 insertions(+), 125 deletions(-)
  19
  20 Index: linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio.h
  21 ===================================================================
  22 --- linux-2.6.27-SLE11_BRANCH.orig/drivers/s390/cio/qdio.h
  23 +++ linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio.h
  24 @@ -14,7 +14,6 @@
  25  #include "chsc.h"
  26
  27  #define QDIO_BUSY_BIT_PATIENCE         100     /* 100 microseconds */
  28 -#define QDIO_BUSY_BIT_GIVE_UP          2000000 /* 2 seconds = eternity */
  29  #define QDIO_INPUT_THRESHOLD           500     /* 500 microseconds */
  30
  31  /*
  32 @@ -195,12 +194,6 @@ struct qdio_input_q {
  33  };
  34
  35  struct qdio_output_q {
  36 -       /* failed siga-w attempts*/
  37 -       atomic_t busy_siga_counter;
  38 -
  39 -       /* start time of busy condition */
  40 -       u64 timestamp;
  41 -
  42         /* PCIs are enabled for the queue */
  43         int pci_out_enabled;
  44
  45 Index: linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio_main.c
  46 ===================================================================
  47 --- linux-2.6.27-SLE11_BRANCH.orig/drivers/s390/cio/qdio_main.c
  48 +++ linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio_main.c
  49 @@ -74,7 +74,7 @@ static inline int do_siga_input(struct s
  50   * Note: For IQDC unicast queues only the highest priority queue is processed.
  51   */
  52  static inline int do_siga_output(unsigned long schid, unsigned long mask,
  53 -                                u32 *bb, unsigned int fc)
  54 +                                unsigned int *bb, unsigned int fc)
  55  {
  56         register unsigned long __fc asm("0") = fc;
  57         register unsigned long __schid asm("1") = schid;
  58 @@ -278,8 +278,7 @@ static int qdio_siga_sync(struct qdio_q
  59         if (!need_siga_sync(q))
  60                 return 0;
  61
  62 -       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:");
  63 -       DBF_DEV_HEX(DBF_INFO, q->irq_ptr, q, sizeof(void *));
  64 +       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:%1d", q->nr);
  65         qdio_perf_stat_inc(&perf_stats.siga_sync);
  66
  67         cc = do_siga_sync(q->irq_ptr->schid, output, input);
  68 @@ -306,43 +305,34 @@ static inline int qdio_siga_sync_all(str
  69         return qdio_siga_sync(q, ~0U, ~0U);
  70  }
  71
  72 -static inline int qdio_do_siga_output(struct qdio_q *q, unsigned int *busy_bit)
  73 +static int qdio_siga_output(struct qdio_q *q, unsigned int *busy_bit)
  74  {
  75 -       unsigned int fc = 0;
  76         unsigned long schid;
  77 +       unsigned int fc = 0;
  78 +       u64 start_time = 0;
  79 +       int cc;
  80
  81 -       if (!is_qebsm(q))
  82 -               schid = *((u32 *)&q->irq_ptr->schid);
  83 -       else {
  84 +       if (is_qebsm(q)) {
  85                 schid = q->irq_ptr->sch_token;
  86                 fc |= 0x80;
  87         }
  88 -       return do_siga_output(schid, q->mask, busy_bit, fc);
  89 -}
  90 -
  91 -static int qdio_siga_output(struct qdio_q *q)
  92 -{
  93 -       int cc;
  94 -       u32 busy_bit;
  95 -       u64 start_time = 0;
  96 +       else
  97 +               schid = *((u32 *)&q->irq_ptr->schid);
  98
  99 -       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
 100 -       qdio_perf_stat_inc(&perf_stats.siga_out);
 101  again:
 102 -       cc = qdio_do_siga_output(q, &busy_bit);
 103 -       if (queue_type(q) == QDIO_IQDIO_QFMT && cc == 2 && busy_bit) {
 104 -               DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w bb:%2d", q->nr);
 105 +       cc = do_siga_output(schid, q->mask, busy_bit, fc);
 106
 107 -               if (!start_time)
 108 +       /* hipersocket busy condition */
 109 +       if (*busy_bit) {
 110 +               WARN_ON(queue_type(q) != QDIO_IQDIO_QFMT || cc != 2);
 111 +
 112 +               if (!start_time) {
 113                         start_time = get_usecs();
 114 -               else if ((get_usecs() - start_time) < QDIO_BUSY_BIT_PATIENCE)
 115 +                       goto again;
 116 +               }
 117 +               if ((get_usecs() - start_time) < QDIO_BUSY_BIT_PATIENCE)
 118                         goto again;
 119         }
 120 -
 121 -       if (cc == 2 && busy_bit)
 122 -               cc |= QDIO_ERROR_SIGA_BUSY;
 123 -       if (cc)
 124 -               DBF_ERROR("%4x SIGA-W:%2d", SCH_NO(q), cc);
 125         return cc;
 126  }
 127
 128 @@ -390,7 +380,7 @@ inline void qdio_stop_polling(struct qdi
 129
 130  static void announce_buffer_error(struct qdio_q *q, int count)
 131  {
 132 -       q->qdio_error = QDIO_ERROR_SLSB_STATE;
 133 +       q->qdio_error |= QDIO_ERROR_SLSB_STATE;
 134
 135         /* special handling for no target buffer empty */
 136         if ((!q->is_input_q &&
 137 @@ -707,69 +697,34 @@ static inline int qdio_outbound_q_moved(
 138                 return 0;
 139  }
 140
 141 -/*
 142 - * VM could present us cc=2 and busy bit set on SIGA-write
 143 - * during reconfiguration of their Guest LAN (only in iqdio mode,
 144 - * otherwise qdio is asynchronous and cc=2 and busy bit there will take
 145 - * the queues down immediately).
 146 - *
 147 - * Therefore qdio_siga_output will try for a short time constantly,
 148 - * if such a condition occurs. If it doesn't change, it will
 149 - * increase the busy_siga_counter and save the timestamp, and
 150 - * schedule the queue for later processing. qdio_outbound_processing
 151 - * will check out the counter. If non-zero, it will call qdio_kick_outbound_q
 152 - * as often as the value of the counter. This will attempt further SIGA
 153 - * instructions. For each successful SIGA, the counter is
 154 - * decreased, for failing SIGAs the counter remains the same, after
 155 - * all. After some time of no movement, qdio_kick_outbound_q will
 156 - * finally fail and reflect corresponding error codes to call
 157 - * the upper layer module and have it take the queues down.
 158 - *
 159 - * Note that this is a change from the original HiperSockets design
 160 - * (saying cc=2 and busy bit means take the queues down), but in
 161 - * these days Guest LAN didn't exist... excessive cc=2 with busy bit
 162 - * conditions will still take the queues down, but the threshold is
 163 - * higher due to the Guest LAN environment.
 164 - *
 165 - * Called from outbound tasklet and do_QDIO handler.
 166 - */
 167 -static void qdio_kick_outbound_q(struct qdio_q *q)
 168 +static int qdio_kick_outbound_q(struct qdio_q *q)
 169  {
 170 -       int rc;
 171 -
 172 -       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "kickoutq:%1d", q->nr);
 173 +       unsigned int busy_bit;
 174 +       int cc;
 175
 176         if (!need_siga_out(q))
 177 -               return;
 178 +               return 0;
 179
 180 -       rc = qdio_siga_output(q);
 181 -       switch (rc) {
 182 +       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
 183 +       qdio_perf_stat_inc(&perf_stats.siga_out);
 184 +
 185 +       cc = qdio_siga_output(q, &busy_bit);
 186 +       switch (cc) {
 187         case 0:
 188 -               /* TODO: improve error handling for CC=0 case */
 189 -               if (q->u.out.timestamp)
 190 -                       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "cc2 rslv:%4x",
 191 -                                     atomic_read(&q->u.out.busy_siga_counter));
 192 -               /* went smooth this time, reset timestamp */
 193 -               q->u.out.timestamp = 0;
 194                 break;
 195 -       /* cc=2 and busy bit */
 196 -       case (2 | QDIO_ERROR_SIGA_BUSY):
 197 -               atomic_inc(&q->u.out.busy_siga_counter);
 198 -
 199 -               /* if the last siga was successful, save timestamp here */
 200 -               if (!q->u.out.timestamp)
 201 -                       q->u.out.timestamp = get_usecs();
 202 -
 203 -               /* if we're in time, don't touch qdio_error */
 204 -               if (get_usecs() - q->u.out.timestamp < QDIO_BUSY_BIT_GIVE_UP) {
 205 -                       tasklet_schedule(&q->tasklet);
 206 -                       break;
 207 -               }
 208 -               DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
 209 -       default:
 210 -               /* for plain cc=1, 2 or 3 */
 211 -               q->qdio_error = rc;
 212 +       case 2:
 213 +               if (busy_bit) {
 214 +                       DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
 215 +                       cc |= QDIO_ERROR_SIGA_BUSY;
 216 +               } else
 217 +                       DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d", q->nr);
 218 +               break;
 219 +       case 1:
 220 +       case 3:
 221 +               DBF_ERROR("%4x SIGA-W:%1d", SCH_NO(q), cc);
 222 +               break;
 223         }
 224 +       return cc;
 225  }
 226
 227  static void qdio_kick_outbound_handler(struct qdio_q *q)
 228 @@ -799,17 +754,7 @@ static void qdio_kick_outbound_handler(s
 229
 230  static void __qdio_outbound_processing(struct qdio_q *q)
 231  {
 232 -       int siga_attempts;
 233 -
 234         qdio_perf_stat_inc(&perf_stats.tasklet_outbound);
 235 -
 236 -       /* see comment in qdio_kick_outbound_q */
 237 -       siga_attempts = atomic_read(&q->u.out.busy_siga_counter);
 238 -       while (siga_attempts--) {
 239 -               atomic_dec(&q->u.out.busy_siga_counter);
 240 -               qdio_kick_outbound_q(q);
 241 -       }
 242 -
 243         BUG_ON(atomic_read(&q->nr_buf_used) < 0);
 244
 245         if (qdio_outbound_q_moved(q))
 246 @@ -1478,10 +1423,10 @@ static inline int buf_in_between(int buf
 247   * @bufnr: first buffer to process
 248   * @count: how many buffers are emptied
 249   */
 250 -static void handle_inbound(struct qdio_q *q, unsigned int callflags,
 251 -                          int bufnr, int count)
 252 +static int handle_inbound(struct qdio_q *q, unsigned int callflags,
 253 +                         int bufnr, int count)
 254  {
 255 -       int used, rc, diff;
 256 +       int used, diff;
 257
 258         if (!q->u.in.polling)
 259                 goto set;
 260 @@ -1519,13 +1464,11 @@ set:
 261
 262         /* no need to signal as long as the adapter had free buffers */
 263         if (used)
 264 -               return;
 265 +               return 0;
 266
 267 -       if (need_siga_in(q)) {
 268 -               rc = qdio_siga_input(q);
 269 -               if (rc)
 270 -                       q->qdio_error = rc;
 271 -       }
 272 +       if (need_siga_in(q))
 273 +               return qdio_siga_input(q);
 274 +       return 0;
 275  }
 276
 277  /**
 278 @@ -1535,11 +1478,11 @@ set:
 279   * @bufnr: first buffer to process
 280   * @count: how many buffers are filled
 281   */
 282 -static void handle_outbound(struct qdio_q *q, unsigned int callflags,
 283 -                           int bufnr, int count)
 284 +static int handle_outbound(struct qdio_q *q, unsigned int callflags,
 285 +                          int bufnr, int count)
 286  {
 287         unsigned char state;
 288 -       int used;
 289 +       int used, rc = 0;
 290
 291         qdio_perf_stat_inc(&perf_stats.outbound_handler);
 292
 293 @@ -1554,14 +1497,17 @@ static void handle_outbound(struct qdio_
 294
 295         if (queue_type(q) == QDIO_IQDIO_QFMT) {
 296                 if (multicast_outbound(q))
 297 -                       qdio_kick_outbound_q(q);
 298 +                       rc = qdio_kick_outbound_q(q);
 299                 else
 300                         /*
 301                          * One siga-w per buffer required for unicast
 302                          * HiperSockets.
 303                          */
 304 -                       while (count--)
 305 -                               qdio_kick_outbound_q(q);
 306 +                       while (count--) {
 307 +                               rc = qdio_kick_outbound_q(q);
 308 +                               if (rc)
 309 +                                       goto out;
 310 +                       }
 311                 goto out;
 312         }
 313
 314 @@ -1573,7 +1519,7 @@ static void handle_outbound(struct qdio_
 315         /* try to fast requeue buffers */
 316         get_buf_state(q, prev_buf(bufnr), &state, 0);
 317         if (state != SLSB_CU_OUTPUT_PRIMED)
 318 -               qdio_kick_outbound_q(q);
 319 +               rc = qdio_kick_outbound_q(q);
 320         else {
 321                 DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "fast-req");
 322                 qdio_perf_stat_inc(&perf_stats.fast_requeue);
 323 @@ -1581,6 +1527,7 @@ static void handle_outbound(struct qdio_
 324  out:
 325         /* Fixme: could wait forever if called from process context */
 326         tasklet_schedule(&q->tasklet);
 327 +       return rc;
 328  }
 329
 330  /**
 331 @@ -1619,14 +1566,12 @@ int do_QDIO(struct ccw_device *cdev, uns
 332                 return -EBUSY;
 333
 334         if (callflags & QDIO_FLAG_SYNC_INPUT)
 335 -               handle_inbound(irq_ptr->input_qs[q_nr], callflags, bufnr,
 336 -                              count);
 337 +               return handle_inbound(irq_ptr->input_qs[q_nr],
 338 +                                     callflags, bufnr, count);
 339         else if (callflags & QDIO_FLAG_SYNC_OUTPUT)
 340 -               handle_outbound(irq_ptr->output_qs[q_nr], callflags, bufnr,
 341 -                               count);
 342 -       else
 343 -               return -EINVAL;
 344 -       return 0;
 345 +               return handle_outbound(irq_ptr->output_qs[q_nr],
 346 +                                      callflags, bufnr, count);
 347 +       return -EINVAL;
 348  }
 349  EXPORT_SYMBOL_GPL(do_QDIO);
 350