Re: [PATCH 2/2] virtio-console: remove unnecessary kmemdup()

From: Jiri Slaby
Date: Mon Aug 02 2021 - 04:40:08 EST

On 02. 08. 21, 10:32, Xianting Tian wrote:

在 2021/8/2 下午3:25, Jiri Slaby 写道:

why is this 2/2? I seem (Lore neither) to find 1/2.
You didn't receive 1/2?
[PATCH 1/2] tty: hvc: pass DMA capable memory to put_chars() <>

Oh, I did, but it's not properly threaded. PLease fix your setup.

On 01. 08. 21, 7:16, Xianting Tian wrote:
hvc framework will never pass stack memory to the put_chars() function,

Am I blind or missing something?

  char c[N_OUTBUF]
  cons_ops[index]->put_chars(vtermnos[index], c, i);

The same here:

hvc_poll_put_char(..., char ch)
   n = hp->ops->put_chars(hp->vtermno, &ch, 1);

AFAICS both of them *pass* a pointer to stack variable.

yes, I discussed the issue with Arnd before in below thread,  you can get the history, thanks <>

So is this a v2? You should have noted that. And what changed from v1 too.

So the calling of kmemdup() is unnecessary, remove it.

Fixes: c4baad5029 ("virtio-console: avoid DMA from stack")

This patch doesn't "Fix" -- it reverts the commit. You should've CCed the author too.

yes, we discussed ther issue in above thread, which we CCed the author.

I don't see any input from the author?

Anyway, 1/2 does not even build, so you will send v3 with all the above fixed, hopefully.