Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/2] virtio-console: remove unnecessary kmemdup() | From | Jiri Slaby <> | Date | Mon, 2 Aug 2021 09:25:13 +0200 |
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Hi,
why is this 2/2? I seem (Lore neither) to find 1/2.
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?
hvc_console_print(...) { 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.
> 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.
> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> > --- > drivers/char/virtio_console.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index 7eaf303a7..4ed3ffb1d 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -1117,8 +1117,6 @@ static int put_chars(u32 vtermno, const char *buf, int count) > { > struct port *port; > struct scatterlist sg[1]; > - void *data; > - int ret; > > if (unlikely(early_put_chars)) > return early_put_chars(vtermno, buf, count); > @@ -1127,14 +1125,8 @@ static int put_chars(u32 vtermno, const char *buf, int count) > if (!port) > return -EPIPE; > > - data = kmemdup(buf, count, GFP_ATOMIC); > - if (!data) > - return -ENOMEM; > - > - sg_init_one(sg, data, count); > - ret = __send_to_port(port, sg, 1, count, data, false); > - kfree(data); > - return ret; > + sg_init_one(sg, buf, count); > + return __send_to_port(port, sg, 1, count, (void *)buf, false); > } > > /* >
-- js suse labs
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