filters/noparallel/noparallel.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdint.h>
  38 #include <string.h>
  39 #include <stdbool.h>
  40 #include <assert.h>
  41
  42 #include <nbdkit-filter.h>
  43
  44 static int thread_model = NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS;
  45
  46 static int
  47 noparallel_config (nbdkit_next_config *next, nbdkit_backend *nxdata,
  48                    const char *key, const char *value)
  49 {
  50   if (strcmp (key, "serialize") == 0 ||
  51       strcmp (key, "serialise") == 0) {
  52     if (strcmp (value, "connections") == 0)
  53       thread_model = NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS;
  54     else if (strcmp (value, "all_requests") == 0 ||
  55              strcmp (value, "all-requests") == 0)
  56       thread_model = NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS;
  57     else if (strcmp (value, "requests") != 0) {
  58       nbdkit_error ("unknown noparallel serialize mode '%s'", value);
  59       return -1;
  60     }
  61     return 0;
  62   }
  63   return next (nxdata, key, value);
  64 }
  65
  66 #define noparallel_config_help \
  67   "serialize=<MODE>      'requests' (default), 'all-requests', or 'connections'.\n" \
  68
  69 /* Apply runtime reduction to thread model. */
  70 static int
  71 noparallel_thread_model (void)
  72 {
  73   return thread_model;
  74 }
  75
  76 static struct nbdkit_filter filter = {
  77   .name              = "noparallel",
  78   .longname          = "nbdkit noparallel filter",
  79   .config            = noparallel_config,
  80   .config_help       = noparallel_config_help,
  81   .thread_model      = noparallel_thread_model,
  82 };
  83
  84 NBDKIT_REGISTER_FILTER (filter)