Module Name: src
Committed By: riastradh
Date: Fri May 8 15:57:24 UTC 2020
Modified Files:
src/sys/dev: random.c
Log Message:
Simplify loops by putting interrupt test at end.
To generate a diff of this commit:
cvs rdiff -u -r1.5 -r1.6 src/sys/dev/random.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/random.c
diff -u src/sys/dev/random.c:1.5 src/sys/dev/random.c:1.6
--- src/sys/dev/random.c:1.5 Fri May 8 15:55:05 2020
+++ src/sys/dev/random.c Fri May 8 15:57:24 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: random.c,v 1.5 2020/05/08 15:55:05 riastradh Exp $ */
+/* $NetBSD: random.c,v 1.6 2020/05/08 15:57:24 riastradh Exp $ */
/*-
* Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -47,7 +47,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: random.c,v 1.5 2020/05/08 15:55:05 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: random.c,v 1.6 2020/05/08 15:57:24 riastradh Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -213,7 +213,6 @@ random_read(dev_t dev, struct uio *uio,
struct nist_hash_drbg drbg;
uint8_t *buf;
int extractflags;
- bool interruptible;
int error;
/* Get a buffer for transfers. */
@@ -258,18 +257,10 @@ random_read(dev_t dev, struct uio *uio,
/* Promptly zero the seed. */
explicit_memset(seed, 0, sizeof seed);
- /*
- * Generate data. Assume no error until failure. No
- * interruption at this point until we've generated at least
- * one block of output.
- */
+ /* Generate data. */
error = 0;
- interruptible = false;
while (uio->uio_resid) {
- size_t n = uio->uio_resid;
-
- /* No more than one buffer's worth. */
- n = MIN(n, RANDOM_BUFSIZE);
+ size_t n = MIN(uio->uio_resid, RANDOM_BUFSIZE);
/*
* Clamp /dev/random output to the entropy capacity and
@@ -286,22 +277,6 @@ random_read(dev_t dev, struct uio *uio,
CTASSERT(sizeof seed <= RANDOM_BUFSIZE);
}
- /* Yield if requested. */
- if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
- preempt();
-
- /*
- * Allow interruption, but only after providing a
- * minimum number of bytes.
- */
- CTASSERT(RANDOM_BUFSIZE >= 256);
- /* Check for interruption. */
- if (__predict_false(curlwp->l_flag & LW_PENDSIG) &&
- interruptible && sigispending(curlwp, 0)) {
- error = EINTR; /* XXX ERESTART? */
- break;
- }
-
/*
* Try to generate a block of data, but if we've hit
* the DRBG reseed interval, reseed.
@@ -348,11 +323,17 @@ random_read(dev_t dev, struct uio *uio,
break;
}
- /*
- * We have generated one block of output, so it is
- * reasonable to allow interruption after this point.
- */
- interruptible = true;
+ /* Yield if requested. */
+ if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
+ preempt();
+
+ /* Check for interruption after at least 256 bytes. */
+ CTASSERT(RANDOM_BUFSIZE >= 256);
+ if (__predict_false(curlwp->l_flag & LW_PENDSIG) &&
+ sigispending(curlwp, 0)) {
+ error = EINTR;
+ break;
+ }
}
out: /* Zero the buffer and free it. */
@@ -401,10 +382,14 @@ random_write(dev_t dev, struct uio *uio,
/* Consume data. */
while (uio->uio_resid) {
- size_t n = uio->uio_resid;
+ size_t n = MIN(uio->uio_resid, RANDOM_BUFSIZE);
- /* No more than one buffer's worth in one step. */
- n = MIN(uio->uio_resid, RANDOM_BUFSIZE);
+ /* Transfer n bytes in and enter them into the pool. */
+ error = uiomove(buf, n, uio);
+ if (error)
+ break;
+ rnd_add_data(&user_rndsource, buf, n, privileged ? n*NBBY : 0);
+ any = true;
/* Yield if requested. */
if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
@@ -416,13 +401,6 @@ random_write(dev_t dev, struct uio *uio,
error = EINTR; /* XXX ERESTART? */
break;
}
-
- /* Transfer n bytes in and enter them into the pool. */
- error = uiomove(buf, n, uio);
- if (error)
- break;
- rnd_add_data(&user_rndsource, buf, n, privileged ? n*NBBY : 0);
- any = true;
}
/* Zero the buffer and free it. */
