+static int __init_rand_distribution(struct thread_data *td, struct fio_file *f)
+{
+ unsigned int range_size, seed;
+ unsigned long nranges;
+ uint64_t fsize;
+
+ range_size = min(td->o.min_bs[DDIR_READ], td->o.min_bs[DDIR_WRITE]);
+ fsize = min(f->real_file_size, f->io_size);
+
+ nranges = (fsize + range_size - 1) / range_size;
+
+ seed = jhash(f->file_name, strlen(f->file_name), 0) * td->thread_number;
+ if (!td->o.rand_repeatable)
+ seed = td->rand_seeds[4];
+
+ if (td->o.random_distribution == FIO_RAND_DIST_ZIPF)
+ zipf_init(&f->zipf, nranges, td->o.zipf_theta.u.f, seed);
+ else if (td->o.random_distribution == FIO_RAND_DIST_PARETO)
+ pareto_init(&f->zipf, nranges, td->o.pareto_h.u.f, seed);
+ else if (td->o.random_distribution == FIO_RAND_DIST_GAUSS)
+ gauss_init(&f->gauss, nranges, td->o.gauss_dev.u.f, seed);
+
+ return 1;
+}
+
+static int init_rand_distribution(struct thread_data *td)
+{
+ struct fio_file *f;
+ unsigned int i;
+ int state;
+
+ if (td->o.random_distribution == FIO_RAND_DIST_RANDOM)
+ return 0;
+
+ state = td_bump_runstate(td, TD_SETTING_UP);
+
+ for_each_file(td, f, i)
+ __init_rand_distribution(td, f);
+
+ td_restore_runstate(td, state);
+
+ return 1;
+}
+
+/*
+ * Check if the number of blocks exceeds the randomness capability of
+ * the selected generator. Tausworthe is 32-bit, the others are fullly
+ * 64-bit capable.
+ */
+static int check_rand_gen_limits(struct thread_data *td, struct fio_file *f,
+ uint64_t blocks)
+{
+ if (blocks <= FRAND32_MAX)
+ return 0;
+ if (td->o.random_generator != FIO_RAND_GEN_TAUSWORTHE)
+ return 0;
+
+ /*
+ * If the user hasn't specified a random generator, switch
+ * to tausworthe64 with informational warning. If the user did
+ * specify one, just warn.
+ */
+ log_info("fio: file %s exceeds 32-bit tausworthe random generator.\n",
+ f->file_name);
+
+ if (!fio_option_is_set(&td->o, random_generator)) {
+ log_info("fio: Switching to tausworthe64. Use the "
+ "random_generator= option to get rid of this "
+ "warning.\n");
+ td->o.random_generator = FIO_RAND_GEN_TAUSWORTHE64;
+ return 0;
+ }
+
+ /*
+ * Just make this information to avoid breaking scripts.
+ */
+ log_info("fio: Use the random_generator= option to switch to lfsr or "
+ "tausworthe64.\n");
+ return 0;
+}
+