Author: delphij
Date: Sun Nov 2 23:30:50 2014
New Revision: 273997
URL: https://svnweb.freebsd.org/changeset/base/273997
Log:
- Make sure random_adaptor accesses happen only when
random_adaptors_lock is held.
- Use sx_sleep instead of tsleep in read and write path to allow
another thread that registers a new random adapter when waiting.
Assert that random_adaptor is not NULL after reacquiring the lock.
- Capture EINTR/ERESTART from sx_sleep to allow the blocking cycle be
stopped when user requests so, while there also make short
read/write's return 0.
- Move M_WAITOK allocations out of lock scope.
In collobration with: kib, markm, ian, jilles
Reviewed by: kib, markm
Approved by: so
Modified:
head/sys/dev/random/random_adaptors.c
Modified: head/sys/dev/random/random_adaptors.c
==============================================================================
--- head/sys/dev/random/random_adaptors.c Sun Nov 2 23:22:22 2014
(r273996)
+++ head/sys/dev/random/random_adaptors.c Sun Nov 2 23:30:50 2014
(r273997)
@@ -171,9 +171,8 @@ random_adaptor_register(const char *name
sx_xlock(&random_adaptors_lock);
LIST_INSERT_HEAD(&random_adaptors_list, rra, rra_entries);
random_adaptor_choose();
- sx_xunlock(&random_adaptors_lock);
-
KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
+ sx_xunlock(&random_adaptors_lock);
}
void
@@ -182,9 +181,9 @@ random_adaptor_deregister(const char *na
struct random_adaptors *rra;
KASSERT(name != NULL, ("invalid input to %s", __func__));
- KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
sx_xlock(&random_adaptors_lock);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
LIST_FOREACH(rra, &random_adaptors_list, rra_entries)
if (strcmp(rra->rra_name, name) == 0) {
LIST_REMOVE(rra, rra_entries);
@@ -208,23 +207,28 @@ random_adaptor_read(struct cdev *dev __u
printf("random: %s %ld\n", __func__, uio->uio_resid);
#endif
- KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
+ random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
sx_slock(&random_adaptors_lock);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
+
/* Let the entropy source do any pre-read setup. */
(random_adaptor->ra_read)(NULL, 0);
/* (Un)Blocking logic */
error = 0;
- while (!random_adaptor->ra_seeded()) {
+ while (!random_adaptor->ra_seeded() && error == 0) {
if (flags & O_NONBLOCK) {
error = EWOULDBLOCK;
break;
}
/* Sleep instead of going into a spin-frenzy */
- tsleep(&random_adaptor, PUSER | PCATCH, "block", hz/10);
+ error = sx_sleep(&random_adaptor, &random_adaptors_lock,
+ PUSER | PCATCH, "randrd", hz/10);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in
%s",
+ __func__));
/* keep tapping away at the pre-read until we seed/unblock. */
(random_adaptor->ra_read)(NULL, 0);
@@ -241,12 +245,10 @@ random_adaptor_read(struct cdev *dev __u
mtx_unlock(&random_read_rate_mtx);
- if (!error) {
+ if (error == 0) {
+ nbytes = uio->uio_resid;
/* The actual read */
-
- random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
-
while (uio->uio_resid && !error) {
c = MIN(uio->uio_resid, PAGE_SIZE);
(random_adaptor->ra_read)(random_buf, c);
@@ -256,11 +258,15 @@ random_adaptor_read(struct cdev *dev __u
/* Let the entropy source do any post-read cleanup. */
(random_adaptor->ra_read)(NULL, 1);
- free(random_buf, M_ENTROPY);
- }
+ if (nbytes != uio->uio_resid && (error == ERESTART ||
+ error == EINTR) )
+ error = 0; /* Return partial read, not error. */
+ }
sx_sunlock(&random_adaptors_lock);
+ free(random_buf, M_ENTROPY);
+
return (error);
}
@@ -269,6 +275,8 @@ random_adaptor_read_rate(void)
{
int ret;
+ sx_assert(&random_adaptors_lock, SA_LOCKED);
+
KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
mtx_lock(&random_read_rate_mtx);
@@ -287,18 +295,20 @@ random_adaptor_write(struct cdev *dev __
{
int c, error = 0;
void *random_buf;
+ ssize_t nbytes;
#ifdef RANDOM_DEBUG
printf("random: %s %zd\n", __func__, uio->uio_resid);
#endif
- KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
+ random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
sx_slock(&random_adaptors_lock);
- random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
- while (uio->uio_resid > 0) {
+ nbytes = uio->uio_resid;
+ while (uio->uio_resid > 0 && error == 0) {
c = MIN(uio->uio_resid, PAGE_SIZE);
error = uiomove(random_buf, c, uio);
if (error)
@@ -306,13 +316,20 @@ random_adaptor_write(struct cdev *dev __
(random_adaptor->ra_write)(random_buf, c);
/* Introduce an annoying delay to stop swamping */
- tsleep(&random_adaptor, PUSER | PCATCH, "block", hz/10);
+ error = sx_sleep(&random_adaptor, &random_adaptors_lock,
+ PUSER | PCATCH, "randwr", hz/10);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in
%s",
+ __func__));
}
- free(random_buf, M_ENTROPY);
-
sx_sunlock(&random_adaptors_lock);
+ if (nbytes != uio->uio_resid && (error == ERESTART ||
+ error == EINTR) )
+ error = 0; /* Partial write, not error. */
+
+ free(random_buf, M_ENTROPY);
+
return (error);
}
@@ -325,10 +342,10 @@ random_adaptor_poll(struct cdev *dev __u
printf("random: %s\n", __func__);
#endif
- KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
-
sx_slock(&random_adaptors_lock);
+ KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
+
if (events & (POLLIN | POLLRDNORM)) {
if (random_adaptor->ra_seeded())
events &= (POLLIN | POLLRDNORM);
@@ -382,9 +399,9 @@ random_sysctl_active_adaptor_handler(SYS
struct sbuf sbuf;
int error;
+ sx_slock(&random_adaptors_lock);
KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
- sx_slock(&random_adaptors_lock);
sbuf_new_for_sysctl(&sbuf, NULL, 16, req);
LIST_FOREACH(rra, &random_adaptors_list, rra_entries)
if (rra->rra_ra == random_adaptor) {
@@ -454,9 +471,9 @@ static void
random_adaptors_seed(void *unused __unused)
{
+ sx_slock(&random_adaptors_lock);
KASSERT(random_adaptor != NULL, ("No active random adaptor in %s",
__func__));
- sx_slock(&random_adaptors_lock);
random_adaptor->ra_reseed();
sx_sunlock(&random_adaptors_lock);
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