Re: [PATCH v3 06/26] s390/pci: Use PCI_STD_NUM_BARS

From: Denis Efremov
Date: Wed Sep 18 2019 - 10:27:05 EST

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@xxxxxxxxxxxxx>
>> Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
>> Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
>> ---
>> 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
>>