2019-09-17 07:04:01

by Denis Efremov (Oracle)

Subject: [PATCH v3 13/26] e1000: Use PCI_STD_NUM_BARS

To iterate through all possible BARs, loop conditions refactored to the
*number* of BARs "i < PCI_STD_NUM_BARS", instead of the index of the last
valid BAR "i <= BAR_5". This is more idiomatic C style and allows to avoid
the fencepost error.

Cc: Jeff Kirsher <[email protected]>
Cc: "David S. Miller" <[email protected]>
Signed-off-by: Denis Efremov <[email protected]>
---
drivers/net/ethernet/intel/e1000/e1000.h | 1 -
drivers/net/ethernet/intel/e1000/e1000_main.c | 2 +-
2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000/e1000.h b/drivers/net/ethernet/intel/e1000/e1000.h
index c40729b2c184..7fad2f24dcad 100644
--- a/drivers/net/ethernet/intel/e1000/e1000.h
+++ b/drivers/net/ethernet/intel/e1000/e1000.h
@@ -45,7 +45,6 @@

#define BAR_0 0
#define BAR_1 1
-#define BAR_5 5

#define INTEL_E1000_ETHERNET_DEVICE(device_id) {\
PCI_DEVICE(PCI_VENDOR_ID_INTEL, device_id)}
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index f703fa58458e..db4fd82036af 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -977,7 +977,7 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto err_ioremap;

if (adapter->need_ioport) {
- for (i = BAR_1; i <= BAR_5; i++) {
+ for (i = BAR_1; i < PCI_STD_NUM_BARS; i++) {
if (pci_resource_len(pdev, i) == 0)
continue;
if (pci_resource_flags(pdev, i) & IORESOURCE_IO) {
--
2.21.0

2019-09-18 09:41:48

by Andrew Murray

Subject: Re: [PATCH v3 13/26] e1000: Use PCI_STD_NUM_BARS

On Mon, Sep 16, 2019 at 11:41:45PM +0300, Denis Efremov wrote:
> To iterate through all possible BARs, loop conditions refactored to the
> *number* of BARs "i < PCI_STD_NUM_BARS", instead of the index of the last
> valid BAR "i <= BAR_5". This is more idiomatic C style and allows to avoid
> the fencepost error.
>
> Cc: Jeff Kirsher <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Signed-off-by: Denis Efremov <[email protected]>
> ---
> drivers/net/ethernet/intel/e1000/e1000.h | 1 -
> drivers/net/ethernet/intel/e1000/e1000_main.c | 2 +-
> 2 files changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000/e1000.h b/drivers/net/ethernet/intel/e1000/e1000.h
> index c40729b2c184..7fad2f24dcad 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000.h
> +++ b/drivers/net/ethernet/intel/e1000/e1000.h
> @@ -45,7 +45,6 @@
>
> #define BAR_0 0
> #define BAR_1 1
> -#define BAR_5 5

No issue with this patch. However I noticed that at least 5 of the network
drivers have these same definitions, which are identical to the pci_barno enum
of include/linux/pci-epf.h. There are mostly used with pci_ioremap_bar and
pci_resource_** macros. I wonder if this is an indicator that these defintions
should live in the core.

Thanks,

Andrew Murray

>
> #define INTEL_E1000_ETHERNET_DEVICE(device_id) {\
> PCI_DEVICE(PCI_VENDOR_ID_INTEL, device_id)}
> diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
> index f703fa58458e..db4fd82036af 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_main.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
> @@ -977,7 +977,7 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> goto err_ioremap;
>
> if (adapter->need_ioport) {
> - for (i = BAR_1; i <= BAR_5; i++) {
> + for (i = BAR_1; i < PCI_STD_NUM_BARS; i++) {
> if (pci_resource_len(pdev, i) == 0)
> continue;
> if (pci_resource_flags(pdev, i) & IORESOURCE_IO) {
> --
> 2.21.0
>