[PATCH] fs: ext4: Fix alignment of cache buffers

[Peter Robinson]

On Wed, Mar 25, 2020 at 8:28 PM Jan Kiszka <jan.kiszka at siemens.com> wrote:
>
> From: Jan Kiszka <jan.kiszka at siemens.com>
>
> We need to align the cache buffer to ARCH_DMA_MINALIGN in order to avoid
> access errors like
>
> CACHE: Misaligned operation at range [be0231e0, be0235e0]
>
> seen on the MCIMX7SABRE.

I've also seen this on some i.MX6 devices such as Wandboard,
Hummingboard Edge and the UDOO Neo. Tested on the later two, thanks
for this fix.

Tested-by: Peter Robinson <pbrobinson at gmail.com>

> Fixes: d5aee659f217 ("fs: ext4: cache extent data")
> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> ---
>  fs/ext4/ext4fs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
> index 1c616a26a2..966b427a97 100644
> --- a/fs/ext4/ext4fs.c
> +++ b/fs/ext4/ext4fs.c
> @@ -288,7 +288,7 @@ int ext_cache_read(struct ext_block_cache *cache, lbaint_t block, int size)
>         if (cache->buf && cache->block == block && cache->size == size)
>                 return 1;
>         ext_cache_fini(cache);
> -       cache->buf = malloc(size);
> +       cache->buf = memalign(ARCH_DMA_MINALIGN, size);
>         if (!cache->buf)
>                 return 0;
>         if (!ext4fs_devread(block, 0, size, cache->buf)) {
> --
> 2.16.4
>
>
> --
> Siemens AG, Corporate Technology, CT RDA IOT SES-DE
> Corporate Competence Center Embedded Linux