target/linux/ipq806x/patches-4.4/019-1-nvmem-core-return-error-for-non-word-aligned-access.patch

   1 From 313a72ff983cc2e00ac4dcb791d40ebf2f9d5718 Mon Sep 17 00:00:00 2001
   2 From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
   3 Date: Tue, 17 Nov 2015 09:12:41 +0000
   4 Subject: nvmem: core: return error for non word aligned access
   5
   6 nvmem providers have restrictions on register strides, so return error
   7 when users attempt to read/write buffers with sizes which are less
   8 than word size.
   9
  10 Without this patch the userspace would continue to try as it does not
  11 get any error from the nvmem core, resulting in a hang or endless loop
  12 in userspace.
  13
  14 Reported-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
  15 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  17 ---
  18  drivers/nvmem/core.c | 6 ++++++
  19  1 file changed, 6 insertions(+)
  20
  21 --- a/drivers/nvmem/core.c
  22 +++ b/drivers/nvmem/core.c
  23 @@ -70,6 +70,9 @@ static ssize_t bin_attr_nvmem_read(struc
  24         if (pos >= nvmem->size)
  25                 return 0;
  26
  27 +       if (count < nvmem->word_size)
  28 +               return -EINVAL;
  29 +
  30         if (pos + count > nvmem->size)
  31                 count = nvmem->size - pos;
  32
  33 @@ -95,6 +98,9 @@ static ssize_t bin_attr_nvmem_write(stru
  34         if (pos >= nvmem->size)
  35                 return 0;
  36
  37 +       if (count < nvmem->word_size)
  38 +               return -EINVAL;
  39 +
  40         if (pos + count > nvmem->size)
  41                 count = nvmem->size - pos;
  42