linux-kernel - Re: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR

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Date:   Thu, 23 May 2019 16:55:03 -0700
From:   Alan Mikhak <alan.mikhak@...ive.com>
To:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        kishon@...com, lorenzo.pieralisi@....com,
        linux-riscv@...ts.infradead.org,
        Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        gustavo.pimentel@...opsys.com, wen.yang99@....com.cn, kjlu@....edu
Subject: Re: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR

+Bjorn Helgaas, +Gustavo Pimentel, +Wen Yang, +Kangjie Lu

On Thu, May 23, 2019 at 2:55 PM Alan Mikhak <alan.mikhak@...ive.com> wrote:
>
> Always skip odd bar when skipping 64bit BARs in pci_epf_test_set_bar()
> and pci_epf_test_alloc_space().
>
> Otherwise, pci_epf_test_set_bar() will call pci_epc_set_bar() on odd loop
> index when skipping reserved 64bit BAR. Moreover, pci_epf_test_alloc_space()
> will call pci_epf_alloc_space() on bind for odd loop index when BAR is 64bit
> but leaks on subsequent unbind by not calling pci_epf_free_space().
>
> Signed-off-by: Alan Mikhak <alan.mikhak@...ive.com>
> Reviewed-by: Paul Walmsley <paul.walmsley@...ive.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 25 ++++++++++++-------------
>  1 file changed, 12 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 27806987e93b..96156a537922 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -389,7 +389,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>
>  static int pci_epf_test_set_bar(struct pci_epf *epf)
>  {
> -       int bar;
> +       int bar, add;
>         int ret;
>         struct pci_epf_bar *epf_bar;
>         struct pci_epc *epc = epf->epc;
> @@ -400,8 +400,14 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
>
>         epc_features = epf_test->epc_features;
>
> -       for (bar = BAR_0; bar <= BAR_5; bar++) {
> +       for (bar = BAR_0; bar <= BAR_5; bar += add) {
>                 epf_bar = &epf->bar[bar];
> +               /*
> +                * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64
> +                * if the specific implementation required a 64-bit BAR,
> +                * even if we only requested a 32-bit BAR.
> +                */
> +               add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
>
>                 if (!!(epc_features->reserved_bar & (1 << bar)))
>                         continue;
> @@ -413,13 +419,6 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
>                         if (bar == test_reg_bar)
>                                 return ret;
>                 }
> -               /*
> -                * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64
> -                * if the specific implementation required a 64-bit BAR,
> -                * even if we only requested a 32-bit BAR.
> -                */
> -               if (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
> -                       bar++;
>         }
>
>         return 0;
> @@ -431,7 +430,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
>         struct device *dev = &epf->dev;
>         struct pci_epf_bar *epf_bar;
>         void *base;
> -       int bar;
> +       int bar, add;
>         enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>         const struct pci_epc_features *epc_features;
>
> @@ -445,8 +444,10 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
>         }
>         epf_test->reg[test_reg_bar] = base;
>
> -       for (bar = BAR_0; bar <= BAR_5; bar++) {
> +       for (bar = BAR_0; bar <= BAR_5; bar += add) {
>                 epf_bar = &epf->bar[bar];
> +               add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
> +
>                 if (bar == test_reg_bar)
>                         continue;
>
> @@ -459,8 +460,6 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
>                         dev_err(dev, "Failed to allocate space for BAR%d\n",
>                                 bar);
>                 epf_test->reg[bar] = base;
> -               if (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
> -                       bar++;
>         }
>
>         return 0;
> --
> 2.7.4
>