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

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Date:   Tue, 11 Jun 2019 11:08:45 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Alan Mikhak <alan.mikhak@...ive.com>
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        kishon@...com, linux-riscv@...ts.infradead.org, palmer@...ive.com,
        paul.walmsley@...ive.com
Subject: Re: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR

On Thu, May 23, 2019 at 02:55:40PM -0700, Alan Mikhak 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(-)

Applied to pci/endpoint for v5.3, thanks.

Lorenzo

> 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
>