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staging: lustre: replace cfs_srand() calls with add_device_randomness(). 

The only places that cfs_srand is called, the random bits are
mixed with bits from get_random_bytes().  So it is equally effective
to add entropy to either pool.
So we can replace calls to cfs_srand() with calls that add the
entropy with add_device_randomness().  That function adds time-based
entropy, so we can discard the ktime_get_ts64 calls.

One location in lustre_handles.c only adds timebased
entropy.  This cannot improve the entropy provided by get_random_bytes(),
so just discard that call.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown 2017-12-18 12:41:42 +11:00 committed by Greg Kroah-Hartman
parent bcfa98a507
commit 30f4236aaf
3 changed files with 13 additions and 26 deletions
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15
drivers/staging/lustre/lnet/lnet/router.c
View File

@ -238,28 +238,25 @@ lnet_find_net_locked(__u32 net)
static void lnet_shuffle_seed(void)
{
static int seeded;
__u32 lnd_type, seed[2];
struct timespec64 ts;
struct lnet_ni *ni;
if (seeded)
return;
cfs_get_random_bytes(seed, sizeof(seed));
/*
* Nodes with small feet have little entropy
* the NID for this node gives the most entropy in the low bits
*/
list_for_each_entry(ni, &the_lnet.ln_nis, ni_list) {
lnd_type = LNET_NETTYP(LNET_NIDNET(ni->ni_nid));
__u32 lnd_type, seed;
if (lnd_type != LOLND)
seed[0] ^= (LNET_NIDADDR(ni->ni_nid) | lnd_type);
lnd_type = LNET_NETTYP(LNET_NIDNET(ni->ni_nid));
if (lnd_type != LOLND) {
seed = (LNET_NIDADDR(ni->ni_nid) | lnd_type);
add_device_randomness(&seed, sizeof(seed));
}
}
ktime_get_ts64(&ts);
cfs_srand(ts.tv_sec ^ seed[0], ts.tv_nsec ^ seed[1]);
seeded = 1;
}

17
drivers/staging/lustre/lustre/llite/super25.c
View File

@ -86,8 +86,7 @@ MODULE_ALIAS_FS("lustre");
static int __init lustre_init(void)
{
struct lnet_process_id lnet_id;
struct timespec64 ts;
int i, rc, seed[2];
int i, rc;
BUILD_BUG_ON(sizeof(LUSTRE_VOLATILE_HDR) !=
LUSTRE_VOLATILE_HDR_LEN + 1);
@ -126,22 +125,20 @@ static int __init lustre_init(void)
goto out_debugfs;
}
cfs_get_random_bytes(seed, sizeof(seed));
/* Nodes with small feet have little entropy. The NID for this
* node gives the most entropy in the low bits
*/
for (i = 0;; i++) {
u32 seed;
if (LNetGetId(i, &lnet_id) == -ENOENT)
break;
if (LNET_NETTYP(LNET_NIDNET(lnet_id.nid)) != LOLND)
seed[0] ^= LNET_NIDADDR(lnet_id.nid);
if (LNET_NETTYP(LNET_NIDNET(lnet_id.nid)) != LOLND) {
seed = LNET_NIDADDR(lnet_id.nid);
add_device_randomness(&seed, sizeof(seed));
}
}
ktime_get_ts64(&ts);
cfs_srand(ts.tv_sec ^ seed[0], ts.tv_nsec ^ seed[1]);
rc = vvp_global_init();
if (rc != 0)
goto out_sysfs;

7
drivers/staging/lustre/lustre/obdclass/lustre_handles.c
View File

@ -181,8 +181,6 @@ EXPORT_SYMBOL(class_handle_free_cb);
int class_handle_init(void)
{
struct handle_bucket *bucket;
struct timespec64 ts;
int seed[2];
LASSERT(!handle_hash);
@ -198,11 +196,6 @@ int class_handle_init(void)
spin_lock_init(&bucket->lock);
}
/** bug 21430: add randomness to the initial base */
cfs_get_random_bytes(seed, sizeof(seed));
ktime_get_ts64(&ts);
cfs_srand(ts.tv_sec ^ seed[0], ts.tv_nsec ^ seed[1]);
cfs_get_random_bytes(&handle_base, sizeof(handle_base));
LASSERT(handle_base != 0ULL);