Re: [PATCH 8/9] vdap: solidrun: Replace deprecated PCI functions

Christophe JAILLET
2024-08-19T23:59:38Z

Le 19/08/2024 à 18:51, Philipp Stanner a écrit :
> solidrun utilizes pcim_iomap_regions(), which has been deprecated by the
> PCI subsystem in commit e354bb84a4c1 ("PCI: Deprecate
> pcim_iomap_table(), pcim_iomap_regions_request_all()"), among other
> things because it forces usage of quite a complicated bitmask mechanism.
> The bitmask handling code can entirely be removed by replacing
> pcim_iomap_regions() and pcim_iomap_table().
>
> Replace pcim_iomap_regions() and pcim_iomap_table() with
> pci_iomap_region().
>
> Signed-off-by: Philipp Stanner <pstanner@redhat.com>
> ---
> drivers/vdpa/solidrun/snet_main.c | 47 +++++++++++--------------------
> 1 file changed, 16 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/vdpa/solidrun/snet_main.c b/drivers/vdpa/solidrun/snet_main.c
> index 99428a04068d..abf027ca35e1 100644
> --- a/drivers/vdpa/solidrun/snet_main.c
> +++ b/drivers/vdpa/solidrun/snet_main.c
> @@ -556,33 +556,24 @@ static const struct vdpa_config_ops snet_config_ops = {
> static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
> {
> char name[50];
> - int ret, i, mask = 0;
> + int i;
> +
> + snprintf(name, sizeof(name), "psnet[%s]-bars", pci_name(pdev));
> +
> /* 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);
> - }
> -
> - /* No BAR can be used.. */
> - if (!mask) {
> - SNET_ERR(pdev, "Failed to find a PCI BAR\n");
> - return -ENODEV;
> - }
> -
> - snprintf(name, sizeof(name), "psnet[%s]-bars", pci_name(pdev));
> - ret = pcim_iomap_regions(pdev, mask, name);
> - if (ret) {
> - SNET_ERR(pdev, "Failed to request and map PCI BARs\n");
> - return ret;
> - }
> + if (pci_resource_len(pdev, i)) {
> + psnet->bars[i] = pcim_iomap_region(pdev, i, name);

Hi,

Unrelated to the patch, but is is safe to have 'name' be on the stack?

pcim_iomap_region()
--> __pcim_request_region()
--> __pcim_request_region_range()
--> request_region() or __request_mem_region()
--> __request_region()
--> __request_region_locked()
--> res->name = name;

So an address on the stack ends in the 'name' field of a "struct resource".

According to a few grep, it looks really unusual.

I don't know if it is used, but it looks strange to me.

If it is an issue, it was apparently already there before this patch.

> + if (IS_ERR(psnet->bars[i])) {
> + SNET_ERR(pdev, "Failed to request and map PCI BARs\n");
> + return PTR_ERR(psnet->bars[i]);
> + }
> + }
>
> - for (i = 0; i < PCI_STD_NUM_BARS; i++) {
> - if (mask & (1 << i))
> - psnet->bars[i] = pcim_iomap_table(pdev)[i];
> }
>
> return 0;
> @@ -591,18 +582,15 @@ static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
> static int snet_open_vf_bar(struct pci_dev *pdev, struct snet *snet)
> {
> char name[50];
> - int ret;
>
> snprintf(name, sizeof(name), "snet[%s]-bar", pci_name(pdev));
> /* 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);

Same

Just my 2c.

CJ

> + 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;
> }
>
> @@ -650,15 +638,12 @@ 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;
> + int 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 */