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Message-ID: <08e922383c726a72574ea24eb2db520d40de4c47.camel@redhat.com>
Date: Fri, 13 Dec 2024 19:39:46 +0100
From: Philipp Stanner <pstanner@...hat.com>
To: Stefano Garzarella <sgarzare@...hat.com>
Cc: Alvaro Karsz <alvaro.karsz@...id-run.com>, "Michael S. Tsirkin"
<mst@...hat.com>, Jason Wang <jasowang@...hat.com>, Xuan Zhuo
<xuanzhuo@...ux.alibaba.com>, Eugenio Pérez
<eperezma@...hat.com>, virtualization@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] vdpa: solidrun: Replace deprecated PCI functions
On Fri, 2024-12-13 at 16:10 +0100, Stefano Garzarella wrote:
> On Wed, Dec 11, 2024 at 11:47:05AM +0100, Philipp Stanner wrote:
> > The PCI functions
> >
> > pcim_iomap_regions()
> > pcim_iounmap_regions()
> > pcim_iomap_table()
> >
> > have been deprecated by the PCI subsystem.
> >
> > Replace these functions with their successors pcim_iomap_region()
> > and
> > pcim_iounmap_region().
> >
> > Signed-off-by: Philipp Stanner <pstanner@...hat.com>
> > ---
> > Changes in v3:
> > - Move __iomem *io declaration into the loop. (Stefano)
> >
> > Changes in v2:
> > - Fix build warning because of dead variable.
> > - Make "bars_found" a boolean, since only true or false are
> > relevant.
> > ---
> > drivers/vdpa/solidrun/snet_main.c | 56 ++++++++++++++--------------
> > ---
> > 1 file changed, 26 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/vdpa/solidrun/snet_main.c
> > b/drivers/vdpa/solidrun/snet_main.c
> > index c8b74980dbd1..643e335f00f1 100644
> > --- a/drivers/vdpa/solidrun/snet_main.c
> > +++ b/drivers/vdpa/solidrun/snet_main.c
> > @@ -556,59 +556,58 @@ static const struct vdpa_config_ops
> > snet_config_ops = {
> > static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet
> > *psnet)
> > {
> > char *name;
> > - int ret, i, mask = 0;
> > + unsigned short i;
> > + bool bars_found = false;
> > +
> > + name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "psnet[%s]-
> > bars", pci_name(pdev));
> > + if (!name)
> > + return -ENOMEM;
> > +
> > /* We don't know which BAR will be used to communicate..
> > * We will map every bar with len > 0.
> > *
> > * Later, we will discover the BAR and unmap all other
> > BARs.
> > */
> > for (i = 0; i < PCI_STD_NUM_BARS; i++) {
> > - if (pci_resource_len(pdev, i))
> > - mask |= (1 << i);
> > + void __iomem *io;
> > +
> > + if (pci_resource_len(pdev, i) == 0)
> > + continue;
> > +
> > + io = pcim_iomap_region(pdev, i, name);
> > + if (IS_ERR(io)) {
> > + SNET_ERR(pdev, "Failed to request and map
> > PCI BARs\n");
> > + return PTR_ERR(io);
> > + }
> > +
> > + psnet->bars[i] = io;
> > + bars_found = true;
> > }
> >
> > /* No BAR can be used.. */
> > - if (!mask) {
> > + if (!bars_found) {
> > SNET_ERR(pdev, "Failed to find a PCI BAR\n");
> > return -ENODEV;
> > }
> >
> > - name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "psnet[%s]-
> > bars", pci_name(pdev));
> > - if (!name)
> > - return -ENOMEM;
> > -
> > - ret = pcim_iomap_regions(pdev, mask, name);
> > - if (ret) {
> > - SNET_ERR(pdev, "Failed to request and map PCI
> > BARs\n");
> > - return ret;
> > - }
> > -
> > - for (i = 0; i < PCI_STD_NUM_BARS; i++) {
> > - if (mask & (1 << i))
> > - psnet->bars[i] =
> > pcim_iomap_table(pdev)[i];
> > - }
> > -
> > return 0;
> > }
> >
> > static int snet_open_vf_bar(struct pci_dev *pdev, struct snet
> > *snet)
> > {
> > char *name;
> > - int ret;
> >
> > name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "snet[%s]-
> > bars", pci_name(pdev));
> > if (!name)
> > return -ENOMEM;
> >
> > /* Request and map BAR */
> > - ret = pcim_iomap_regions(pdev, BIT(snet->psnet-
> > >cfg.vf_bar), name);
> > - if (ret) {
> > + snet->bar = pcim_iomap_region(pdev, snet->psnet-
> > >cfg.vf_bar, name);
>
> Could we also use a temporary variable here as we did in
> psnet_open_pf_bar()?
We can. Some maintainers want it so, others so
>
> It seems to me that no one uses `!snet->bar` for now to check whether
> they are configured or not, but maybe better to prevent, WDYT?
So it seems that this driver is a bit special as its probe() function
can take different paths running into one of the respective request
functions.
Doesn't look to me as if pcim_iomap_region() could fail and the driver
would still load?
Anyways, better safe than sorry. If you think it's safer I can modify
it so those pointers are valid or NULL.
P.
>
> Thanks,
> Stefano
>
> > + if (IS_ERR(snet->bar)) {
> > SNET_ERR(pdev, "Failed to request and map PCI BAR
> > for a VF\n");
> > - return ret;
> > + return PTR_ERR(snet->bar);
> > }
> >
> > - snet->bar = pcim_iomap_table(pdev)[snet->psnet-
> > >cfg.vf_bar];
> > -
> > return 0;
> > }
> >
> > @@ -656,15 +655,12 @@ static int psnet_detect_bar(struct psnet
> > *psnet, u32 off)
> >
> > static void psnet_unmap_unused_bars(struct pci_dev *pdev, struct
> > psnet *psnet)
> > {
> > - int i, mask = 0;
> > + unsigned short i;
> >
> > for (i = 0; i < PCI_STD_NUM_BARS; i++) {
> > if (psnet->bars[i] && i != psnet->barno)
> > - mask |= (1 << i);
> > + pcim_iounmap_region(pdev, i);
> > }
> > -
> > - if (mask)
> > - pcim_iounmap_regions(pdev, mask);
> > }
> >
> > /* Read SNET config from PCI BAR */
> > --
> > 2.47.1
> >
>
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