Messages in this thread | | | Subject | Re: [PATCH v4 1/2] tty: hvc: pass DMA capable memory to put_chars() | From | Xianting Tian <> | Date | Sat, 7 Aug 2021 23:00:27 +0800 |
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在 2021/8/6 下午10:51, Arnd Bergmann 写道: > On Fri, Aug 6, 2021 at 5:01 AM Xianting Tian > <xianting.tian@linux.alibaba.com> wrote: >> @@ -163,6 +155,13 @@ static void hvc_console_print(struct console *co, const char *b, >> if (vtermnos[index] == -1) >> return; >> >> + list_for_each_entry(hp, &hvc_structs, next) >> + if (hp->vtermno == vtermnos[index]) >> + break; >> + >> + c = hp->c; >> + >> + spin_lock_irqsave(&hp->c_lock, flags); > The loop looks like it might race against changes to the list. It seems strange > that the print function has to actually search for the structure here. > > It may be better to have yet another array for the buffer pointers next to > the cons_ops[] and vtermnos[] arrays. I will make the change in v5, thanks. > >> +/* >> + * These sizes are most efficient for vio, because they are the >> + * native transfer size. We could make them selectable in the >> + * future to better deal with backends that want other buffer sizes. >> + */ >> +#define N_OUTBUF 16 >> +#define N_INBUF 16 >> + >> +#define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) > I think you need a higher alignment for DMA buffers, instead of sizeof(long), > I would suggest ARCH_DMA_MINALIGN.
thanks, I will fix it in v5:
#define __ALIGNED__ __attribute__((__aligned__(ARCH_DMA_MINALIGN)))
> > Arnd
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