On Fri, Feb 17, 2017 at 11:42:45PM +0300, Jan Dakinevich wrote:
> The buffer is used by virtio console driver as DMA buffer. Since v4.9
> (if VMAP_STACK is enabled) we shouldn't use the stack for DMA.
You shouldn't use 'static' data either, that's not always guaranteed to
be DMA-able, right?
>
> Signed-off-by: Jan Dakinevich <jan.dakinevich@xxxxxxxxx>
> ---
> drivers/tty/hvc/hvc_console.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
> index 9b5c0fb..1ce6aaf 100644
> --- a/drivers/tty/hvc/hvc_console.c
> +++ b/drivers/tty/hvc/hvc_console.c
> @@ -143,10 +143,15 @@ static struct hvc_struct *hvc_get_by_index(int index)
> static void hvc_console_print(struct console *co, const char *b,
> unsigned count)
> {
> - char c[N_OUTBUF] __ALIGNED__;
> unsigned i = 0, n = 0;
> int r, donecr = 0, index = co->index;
>
> + /*
> + * Access to the buffer is serialized by console_sem in caller code from
> + * kernel/printk/printk.c
> + */
> + static char c[N_OUTBUF] __ALIGNED__;
What about allocating it dynamically? That's the correct thing to do.
thanks,
greg k-h
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