linux-kernel - Re: [PATCH v3 06/26] s390/pci: Use PCI_STD_NUM

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Message-ID: <c4496d3d-14c1-ffe7-fa38-0caffe81db54@linux.com>
Date:   Wed, 18 Sep 2019 17:26:59 +0300
From:   Denis Efremov <efremov@...ux.com>
To:     Andrew Murray <andrew.murray@....com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-s390@...r.kernel.org,
        Sebastian Ott <sebott@...ux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@...ibm.com>
Subject: Re: [PATCH v3 06/26] s390/pci: Use PCI_STD_NUM_BARS

On 9/18/19 11:58 AM, Andrew Murray wrote:
> 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@...ux.ibm.com>
>> Cc: Gerald Schaefer <gerald.schaefer@...ibm.com>
>> Signed-off-by: Denis Efremov <efremov@...ux.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?
> 

This fix was suggested by Bjorn in v1 review:
https://lkml.org/lkml/2019/8/12/997


> 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
>>