Re: [PATCH 5.12 237/242] drm/ast: Remove reference to struct drm_device.pdev

[Greg Kroah-Hartman]

On Mon, Jul 19, 2021 at 07:43:39PM +0800, Xiaotian Feng wrote:
> On Mon, Jul 19, 2021 at 7:23 PM Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Mon, Jul 19, 2021 at 05:57:30PM +0800, Xiaotian Feng wrote:
> > > On Fri, Jul 16, 2021 at 5:13 AM Greg Kroah-Hartman
> > > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > From: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > > >
> > > > commit 0ecb51824e838372e01330752503ddf9c0430ef7 upstream.
> > > >
> > > > Using struct drm_device.pdev is deprecated. Upcast with to_pci_dev()
> > > > from struct drm_device.dev to get the PCI device structure.
> > > >
> > > > v9:
> > > >         * fix remaining pdev references
> > > >
> > > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > > > Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
> > > > Fixes: ba4e0339a6a3 ("drm/ast: Fixed CVE for DP501")
> > > > Cc: KuoHsiang Chou <kuohsiang_chou@xxxxxxxxxxxxxx>
> > > > Cc: kernel test robot <lkp@xxxxxxxxx>
> > > > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > > > Cc: Dave Airlie <airlied@xxxxxxxxxx>
> > > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > > > Link: https://patchwork.freedesktop.org/patch/msgid/20210429105101.25667-2-tzimmermann@xxxxxxx
> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > > > ---
> > > >  drivers/gpu/drm/ast/ast_main.c |    5 ++---
> > > >  1 file changed, 2 insertions(+), 3 deletions(-)
> > > >
> > > > --- a/drivers/gpu/drm/ast/ast_main.c
> > > > +++ b/drivers/gpu/drm/ast/ast_main.c
> > > > @@ -411,7 +411,6 @@ struct ast_private *ast_device_create(co
> > > >                 return ast;
> > > >         dev = &ast->base;
> > > >
> > > > -       dev->pdev = pdev;
> > > >         pci_set_drvdata(pdev, dev);
> > > >
> > > >         ast->regs = pcim_iomap(pdev, 1, 0);
> > > > @@ -453,8 +452,8 @@ struct ast_private *ast_device_create(co
> > > >
> > > >         /* map reserved buffer */
> > > >         ast->dp501_fw_buf = NULL;
> > > > -       if (dev->vram_mm->vram_size < pci_resource_len(dev->pdev, 0)) {
> > > > -               ast->dp501_fw_buf = pci_iomap_range(dev->pdev, 0, dev->vram_mm->vram_size, 0);
> > > > +       if (dev->vram_mm->vram_size < pci_resource_len(pdev, 0)) {
> > > > +               ast->dp501_fw_buf = pci_iomap_range(pdev, 0, dev->vram_mm->vram_size, 0);
> > > >                 if (!ast->dp501_fw_buf)
> > > >                         drm_info(dev, "failed to map reserved buffer!\n");
> > > >         }
> > > >
> > >
> > > Hi Greg,
> > >
> > >      This backport is incomplete for 5.10 kernel,  kernel is panicked
> > > on RIP: ast_device_create+0x7d.  When I look into the crash code, I
> > > found
> > >
> > > struct ast_private *ast_device_create(struct drm_driver *drv,
> > >                                       struct pci_dev *pdev,
> > >                                       unsigned long flags)
> > > {
> > > .......
> > >         dev->pdev = pdev;  // This is removed
> > >         pci_set_drvdata(pdev, dev);
> > >
> > >         ast->regs = pcim_iomap(pdev, 1, 0);
> > >         if (!ast->regs)
> > >                 return ERR_PTR(-EIO);
> > >
> > >         /*
> > >          * If we don't have IO space at all, use MMIO now and
> > >          * assume the chip has MMIO enabled by default (rev 0x20
> > >          * and higher).
> > >          */
> > >         if (!(pci_resource_flags(dev->pdev, 2) & IORESOURCE_IO)) { //
> > > dev->pdev is in used here.
> > >                 drm_info(dev, "platform has no IO space, trying MMIO\n");
> > >                 ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
> > >         }
> > >
> > >         That's because commit 46fb883c3d0d8a823ef995ddb1f9b0817dea6882
> > > is not backported to 5.10 kernel.
> >
> > So what should I do here?  Backport that commit (was was not called
> > out), or just revert this?
> >
> I think we can just simply revert the patch. Because commit 46fb883c
> removed drm_device.pdev usage,
> then commit ba4e0339 used drm_device.pdev again. Since commit 46fb883c
> is not in 5.10.50 kernel,
> it's not a stable fix.

Now qropped, thanks.

greg k-h