D14684.diff
No OneTemporary
Actions

Size

1 KB

Referenced Files

None

Subscribers

None

D14684.diff
View Options

	Index: head/sys/dev/random/randomdev.c
	===================================================================
	--- head/sys/dev/random/randomdev.c
	+++ head/sys/dev/random/randomdev.c
	@@ -130,7 +130,13 @@
	uint8_t *random_buf;
	int error, spamcount;
	ssize_t read_len, total_read, c;
	+ /* 16 MiB takes about 0.08 s CPU time on my 2017 AMD Zen CPU */
	+#define SIGCHK_PERIOD (16 * 1024 * 1024)
	+ const size_t sigchk_period = SIGCHK_PERIOD;

	+ CTASSERT(SIGCHK_PERIOD % PAGE_SIZE == 0);
	+#undef SIGCHK_PERIOD
	+
	random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
	p_random_alg_context->ra_pre_read();
	error = 0;
	@@ -167,11 +173,22 @@
	read_len = MIN(read_len, PAGE_SIZE);
	p_random_alg_context->ra_read(random_buf, read_len);
	c = MIN(uio->uio_resid, read_len);
	+ /*
	+ * uiomove() may yield the CPU before each 'c' bytes
	+ * (up to PAGE_SIZE) are copied out.
	+ */
	error = uiomove(random_buf, c, uio);
	total_read += c;
	+ /*
	+ * Poll for signals every few MBs to avoid very long
	+ * uninterruptible syscalls.
	+ */
	+ if (error == 0 && uio->uio_resid != 0 &&
	+ total_read % sigchk_period == 0)
	+ error = tsleep_sbt(&random_alg_context, PCATCH,
	+ "randrd", SBT_1NS, 0, C_HARDCLOCK);
	}
	- if (total_read != uio->uio_resid && (error == ERESTART \|\| error == EINTR))
	- /* Return partial read, not error. */
	+ if (error == ERESTART \|\| error == EINTR)
	error = 0;
	}
	free(random_buf, M_ENTROPY);