> > This merge reduces code size by unifying the approach for
> > sending scatter-lists and regular buffers. Any type of
> > write operation (splice, write, put_chars) will now allocate
> > a port_buffer and send_buf() and free_buf() can always be used.
>
> Thanks!
> This looks much nicer and simpler. I just have some comments below.
OK, good to hear that you agree to this kind of change. I'll do a respin
of this patch fixing the issues you have pointed out.
> > static void free_buf(struct port_buffer *buf)
> > {
> > + int i;
> > +
> > kfree(buf->buf);
>
> this should be done only when !buf->sgpages, or (see below)
Agree, I'll put this statement in an else branch to the if-statement below.
>
> > +
> > + if (buf->sgpages)
> > + for (i = 0; i < buf->sgpages; i++) {
> > + struct page *page = sg_page(&buf->sg[i]);
> > + if (!page)
> > + break;
> > + put_page(page);
> > + }
> > +
> > kfree(buf);
> > }
> >
> > -static struct port_buffer *alloc_buf(size_t buf_size)
> > +static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
> > + int nrbufs)
> > {
> > struct port_buffer *buf;
> > + size_t alloc_size;
> >
> > - buf = kmalloc(sizeof(*buf), GFP_KERNEL);
> > + /* Allocate buffer and the scatter list */
> > + alloc_size = sizeof(*buf) + sizeof(struct scatterlist) * nrbufs;
>
> This allocates one redundant sg entry when nrbuf > 0,
> but I think it is OK. (just a comment)
I did this on purpose for the sake of simplicity, but I can
change this to something like:
alloc_size = sizeof(*buf) + sizeof(buf->sg) * max(nrbufs - 1, 1);
> > + buf = kmalloc(alloc_size, GFP_ATOMIC);
>
> This should be kzalloc(), or buf->buf and others are not initialized,
> which will cause unexpected kfree bug at kfree(buf->buf) in free_buf.
Agree, kzalloc() is better in this case.
> > if (!buf)
> > goto fail;
> > - buf->buf = kzalloc(buf_size, GFP_KERNEL);
> > +
> > + buf->sgpages = nrbufs;
> > + if (nrbufs > 0)
> > + return buf;
> > +
> > + buf->buf = kmalloc(buf_size, GFP_ATOMIC);
>
> You can also use kzalloc here as previous code does.
> But if the reason why using kzalloc comes from the security,
> I think kmalloc is enough here, since the host can access
> all the guest pages anyway.
With this new patch alloc_buf() is used both for both RX and TX.
The out_vq did previously use malloc(). But I have preserved
the legacy behavior for the in_vq by calling memset() in function
fill_queue().
Thanks,
Sjur
