lkml.org 
[lkml]   [2013]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 59/88] hw_random: make buffer usable in scatterlist.
    Date
    3.5.7.8 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Rusty Russell <rusty@rustcorp.com.au>

    commit f7f154f1246ccc5a0a7e9ce50932627d60a0c878 upstream.

    virtio_rng feeds the randomness buffer handed by the core directly
    into the scatterlist, since commit bb347d98079a547e80bd4722dee1de61e4dca0e8.

    However, if CONFIG_HW_RANDOM=m, the static buffer isn't a linear address
    (at least on most archs). We could fix this in virtio_rng, but it's actually
    far easier to just do it in the core as virtio_rng would have to allocate
    a buffer every time (it doesn't know how much the core will want to read).

    Reported-by: Aurelien Jarno <aurelien@aurel32.net>
    Tested-by: Aurelien Jarno <aurelien@aurel32.net>
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    drivers/char/hw_random/core.c | 19 ++++++++++++++++---
    1 file changed, 16 insertions(+), 3 deletions(-)

    diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
    index 1bafb40..69ae597 100644
    --- a/drivers/char/hw_random/core.c
    +++ b/drivers/char/hw_random/core.c
    @@ -40,6 +40,7 @@
    #include <linux/init.h>
    #include <linux/miscdevice.h>
    #include <linux/delay.h>
    +#include <linux/slab.h>
    #include <asm/uaccess.h>


    @@ -52,8 +53,12 @@ static struct hwrng *current_rng;
    static LIST_HEAD(rng_list);
    static DEFINE_MUTEX(rng_mutex);
    static int data_avail;
    -static u8 rng_buffer[SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES]
    - __cacheline_aligned;
    +static u8 *rng_buffer;
    +
    +static size_t rng_buffer_size(void)
    +{
    + return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
    +}

    static inline int hwrng_init(struct hwrng *rng)
    {
    @@ -116,7 +121,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,

    if (!data_avail) {
    bytes_read = rng_get_data(current_rng, rng_buffer,
    - sizeof(rng_buffer),
    + rng_buffer_size(),
    !(filp->f_flags & O_NONBLOCK));
    if (bytes_read < 0) {
    err = bytes_read;
    @@ -307,6 +312,14 @@ int hwrng_register(struct hwrng *rng)

    mutex_lock(&rng_mutex);

    + /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
    + err = -ENOMEM;
    + if (!rng_buffer) {
    + rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
    + if (!rng_buffer)
    + goto out_unlock;
    + }
    +
    /* Must not register two RNGs with the same name. */
    err = -EEXIST;
    list_for_each_entry(tmp, &rng_list, list) {
    --
    1.8.1.2


    \
     
     \ /
      Last update: 2013-03-14 16:01    [W:3.117 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site