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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-07-18 20:25:54 -1000 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-07-18 20:25:54 -1000 |
commit | 4e106275290bdb015bc16dc48e55d78cc480e7c7 (patch) | |
tree | 0fe35ef231b8219883230e6a39a193ea57ac5418 /drivers | |
parent | f83971912231fe5390d2357442b6c25bb8076d9b (diff) | |
parent | e052dbf554610e2104c5a7518c4d8374bed701bb (diff) | |
download | linux-4e106275290bdb015bc16dc48e55d78cc480e7c7.tar.bz2 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto fixes from Herbert Xu:
"This push fixes a boot hang in virt guests when the virtio RNG is
enabled"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
hwrng: virtio - ensure reads happen after successful probe
hwrng: fetch randomness only after device init
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/char/hw_random/core.c | 47 | ||||
-rw-r--r-- | drivers/char/hw_random/virtio-rng.c | 10 |
2 files changed, 49 insertions, 8 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 334601cc81cf..c4419ea1ab07 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -55,16 +55,41 @@ static DEFINE_MUTEX(rng_mutex); static int data_avail; static u8 *rng_buffer; +static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, + int wait); + static size_t rng_buffer_size(void) { return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES; } +static void add_early_randomness(struct hwrng *rng) +{ + unsigned char bytes[16]; + int bytes_read; + + /* + * Currently only virtio-rng cannot return data during device + * probe, and that's handled in virtio-rng.c itself. If there + * are more such devices, this call to rng_get_data can be + * made conditional here instead of doing it per-device. + */ + bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + if (bytes_read > 0) + add_device_randomness(bytes, bytes_read); +} + static inline int hwrng_init(struct hwrng *rng) { - if (!rng->init) - return 0; - return rng->init(rng); + if (rng->init) { + int ret; + + ret = rng->init(rng); + if (ret) + return ret; + } + add_early_randomness(rng); + return 0; } static inline void hwrng_cleanup(struct hwrng *rng) @@ -304,8 +329,6 @@ int hwrng_register(struct hwrng *rng) { int err = -EINVAL; struct hwrng *old_rng, *tmp; - unsigned char bytes[16]; - int bytes_read; if (rng->name == NULL || (rng->data_read == NULL && rng->read == NULL)) @@ -347,9 +370,17 @@ int hwrng_register(struct hwrng *rng) INIT_LIST_HEAD(&rng->list); list_add_tail(&rng->list, &rng_list); - bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); - if (bytes_read > 0) - add_device_randomness(bytes, bytes_read); + if (old_rng && !rng->init) { + /* + * Use a new device's input to add some randomness to + * the system. If this rng device isn't going to be + * used right away, its init function hasn't been + * called yet; so only use the randomness from devices + * that don't need an init callback. + */ + add_early_randomness(rng); + } + out_unlock: mutex_unlock(&rng_mutex); out: diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index f3e71501de54..e9b15bc18b4d 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -38,6 +38,8 @@ struct virtrng_info { int index; }; +static bool probe_done; + static void random_recv_done(struct virtqueue *vq) { struct virtrng_info *vi = vq->vdev->priv; @@ -67,6 +69,13 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) int ret; struct virtrng_info *vi = (struct virtrng_info *)rng->priv; + /* + * Don't ask host for data till we're setup. This call can + * happen during hwrng_register(), after commit d9e7972619. + */ + if (unlikely(!probe_done)) + return 0; + if (!vi->busy) { vi->busy = true; init_completion(&vi->have_data); @@ -137,6 +146,7 @@ static int probe_common(struct virtio_device *vdev) return err; } + probe_done = true; return 0; } |