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Date:   Wed, 18 Sep 2019 09:58:06 +0100
From:   Andrew Murray <andrew.murray@arm.com>
To:     Denis Efremov <efremov@linux.com>
Cc:     Bjorn Helgaas <bhelgaas@google.com>, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, linux-s390@vger.kernel.org,
        Sebastian Ott <sebott@linux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>
Subject: Re: [PATCH v3 06/26] s390/pci: Use PCI_STD_NUM_BARS
Message-ID: <20190918085805.GY9720@e119886-lin.cambridge.arm.com>
References: <20190916204158.6889-1-efremov@linux.com>
 <20190916204158.6889-7-efremov@linux.com>
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On Mon, Sep 16, 2019 at 11:41:38PM +0300, Denis Efremov wrote:
> Remove local definition PCI_BAR_COUNT for the number of PCI BARs and use
> global one PCI_STD_NUM_BARS instead.
> 
> Acked-by: Sebastian Ott <sebott@linux.ibm.com>
> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
> Signed-off-by: Denis Efremov <efremov@linux.com>
> ---
>  arch/s390/include/asm/pci.h     |  5 +----
>  arch/s390/include/asm/pci_clp.h |  6 +++---
>  arch/s390/pci/pci.c             | 16 ++++++++--------
>  arch/s390/pci/pci_clp.c         |  6 +++---
>  4 files changed, 15 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index a2399eff84ca..3a06c264ea53 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -2,9 +2,6 @@
>  #ifndef __ASM_S390_PCI_H
>  #define __ASM_S390_PCI_H
>  
> -/* must be set before including pci_clp.h */
> -#define PCI_BAR_COUNT	6
> -
>  #include <linux/pci.h>
>  #include <linux/mutex.h>
>  #include <linux/iommu.h>
> @@ -138,7 +135,7 @@ struct zpci_dev {
>  
>  	char res_name[16];
>  	bool mio_capable;
> -	struct zpci_bar_struct bars[PCI_BAR_COUNT];
> +	struct zpci_bar_struct bars[PCI_STD_NUM_BARS];
>  
>  	u64		start_dma;	/* Start of available DMA addresses */
>  	u64		end_dma;	/* End of available DMA addresses */
> diff --git a/arch/s390/include/asm/pci_clp.h b/arch/s390/include/asm/pci_clp.h
> index 50359172cc48..bd2cb4ea7d93 100644
> --- a/arch/s390/include/asm/pci_clp.h
> +++ b/arch/s390/include/asm/pci_clp.h
> @@ -77,7 +77,7 @@ struct mio_info {
>  	struct {
>  		u64 wb;
>  		u64 wt;
> -	} addr[PCI_BAR_COUNT];
> +	} addr[PCI_STD_NUM_BARS];
>  	u32 reserved[6];
>  } __packed;
>  
> @@ -98,9 +98,9 @@ struct clp_rsp_query_pci {
>  	u16 util_str_avail	:  1;	/* utility string available? */
>  	u16 pfgid		:  8;	/* pci function group id */
>  	u32 fid;			/* pci function id */
> -	u8 bar_size[PCI_BAR_COUNT];
> +	u8 bar_size[PCI_STD_NUM_BARS];
>  	u16 pchid;
> -	__le32 bar[PCI_BAR_COUNT];
> +	__le32 bar[PCI_STD_NUM_BARS];
>  	u8 pfip[CLP_PFIP_NR_SEGMENTS];	/* pci function internal path */
>  	u32			: 16;
>  	u8 fmb_len;
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index b0e3b9a0e488..aca372c8e34f 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -43,7 +43,7 @@ static DECLARE_BITMAP(zpci_domain, ZPCI_NR_DEVICES);
>  static DEFINE_SPINLOCK(zpci_domain_lock);
>  
>  #define ZPCI_IOMAP_ENTRIES						\
> -	min(((unsigned long) ZPCI_NR_DEVICES * PCI_BAR_COUNT / 2),	\
> +	min(((unsigned long) ZPCI_NR_DEVICES * PCI_STD_NUM_BARS / 2),	\
>  	    ZPCI_IOMAP_MAX_ENTRIES)
>  
>  static DEFINE_SPINLOCK(zpci_iomap_lock);
> @@ -294,7 +294,7 @@ static void __iomem *pci_iomap_range_mio(struct pci_dev *pdev, int bar,
>  void __iomem *pci_iomap_range(struct pci_dev *pdev, int bar,
>  			      unsigned long offset, unsigned long max)
>  {
> -	if (!pci_resource_len(pdev, bar) || bar >= PCI_BAR_COUNT)
> +	if (bar >= PCI_STD_NUM_BARS || !pci_resource_len(pdev, bar))
>  		return NULL;
>  
>  	if (static_branch_likely(&have_mio))
> @@ -324,7 +324,7 @@ static void __iomem *pci_iomap_wc_range_mio(struct pci_dev *pdev, int bar,
>  void __iomem *pci_iomap_wc_range(struct pci_dev *pdev, int bar,
>  				 unsigned long offset, unsigned long max)
>  {
> -	if (!pci_resource_len(pdev, bar) || bar >= PCI_BAR_COUNT)
> +	if (bar >= PCI_STD_NUM_BARS || !pci_resource_len(pdev, bar))
>  		return NULL;

This looks like a latent bug fix here. If 'bar' is out of range we return
NULL instead accessing an invalid item of an array. Should this not be
a separate patch and tagged as stable?

Thanks,

Andrew Murray

>  
>  	if (static_branch_likely(&have_mio))
> @@ -416,7 +416,7 @@ static void zpci_map_resources(struct pci_dev *pdev)
>  	resource_size_t len;
>  	int i;
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		len = pci_resource_len(pdev, i);
>  		if (!len)
>  			continue;
> @@ -451,7 +451,7 @@ static void zpci_unmap_resources(struct pci_dev *pdev)
>  	if (zpci_use_mio(zdev))
>  		return;
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		len = pci_resource_len(pdev, i);
>  		if (!len)
>  			continue;
> @@ -514,7 +514,7 @@ static int zpci_setup_bus_resources(struct zpci_dev *zdev,
>  	snprintf(zdev->res_name, sizeof(zdev->res_name),
>  		 "PCI Bus %04x:%02x", zdev->domain, ZPCI_BUS_NR);
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		if (!zdev->bars[i].size)
>  			continue;
>  		entry = zpci_alloc_iomap(zdev);
> @@ -551,7 +551,7 @@ static void zpci_cleanup_bus_resources(struct zpci_dev *zdev)
>  {
>  	int i;
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		if (!zdev->bars[i].size || !zdev->bars[i].res)
>  			continue;
>  
> @@ -573,7 +573,7 @@ int pcibios_add_device(struct pci_dev *pdev)
>  	pdev->dev.dma_ops = &s390_pci_dma_ops;
>  	zpci_map_resources(pdev);
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		res = &pdev->resource[i];
>  		if (res->parent || !res->flags)
>  			continue;
> diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
> index 9bdff4defef1..8b729b5f2972 100644
> --- a/arch/s390/pci/pci_clp.c
> +++ b/arch/s390/pci/pci_clp.c
> @@ -145,7 +145,7 @@ static int clp_store_query_pci_fn(struct zpci_dev *zdev,
>  {
>  	int i;
>  
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		zdev->bars[i].val = le32_to_cpu(response->bar[i]);
>  		zdev->bars[i].size = response->bar_size[i];
>  	}
> @@ -164,8 +164,8 @@ static int clp_store_query_pci_fn(struct zpci_dev *zdev,
>  		       sizeof(zdev->util_str));
>  	}
>  	zdev->mio_capable = response->mio_addr_avail;
> -	for (i = 0; i < PCI_BAR_COUNT; i++) {
> -		if (!(response->mio.valid & (1 << (PCI_BAR_COUNT - i - 1))))
> +	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
> +		if (!(response->mio.valid & (1 << (PCI_STD_NUM_BARS - i - 1))))
>  			continue;
>  
>  		zdev->bars[i].mio_wb = (void __iomem *) response->mio.addr[i].wb;
> -- 
> 2.21.0
>