[PATCH] bufio: fix the next_buf calculation

[Michael Chang]

The next_buf is the offset to the next cached block rounded to the size of
bufio->block_size. However the calculation needs the block_size to be in power
of 2 is not always valid. As an example, files with smaller size than
block_size will have the block_size leveled to the size of file which can be
set arbitrary value.

This patch fixes the next_buf calculation to accept any integers.

Signed-off-by: Michael Chang <address@hidden>
---
 grub-core/io/bufio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/io/bufio.c b/grub-core/io/bufio.c
index 22438277d..d0b0f71b6 100644
--- a/grub-core/io/bufio.c
+++ b/grub-core/io/bufio.c
@@ -132,7 +132,7 @@ grub_bufio_read (grub_file_t file, char *buf, grub_size_t 
len)
     return res;
 
   /* Need to read some more.  */
-  next_buf = (file->offset + res + len - 1) & ~((grub_off_t) bufio->block_size 
- 1);
+  next_buf = (grub_divmod64 (file->offset + res + len - 1, bufio->block_size, 
NULL)) * bufio->block_size;
   /* Now read between file->offset + res and bufio->buffer_at.  */
   if (file->offset + res < next_buf)
     {
-- 
2.13.6