2018-07-09 08:46:47

by Nicholas Mc Guire

[permalink] [raw]
Subject: [PATCH] microblaze: warn if of_iomap() failed

of_iomap() can return NULL. The function is void thus error propagation
is not possible but at least a WARN_ON() seems warranted here as a silent
failure might lead to a hard to understand system state.

Signed-off-by: Nicholas Mc Guire <[email protected]>
---

Problem located with experimental coccinelle script

Probably this should be a BUG_ON() as this is such a low level fault that
continuing operations probably makes little sense.

Patch was compiletested with: mmu_defconfig (implies CONFIG_PCI_XILINX=y)

Patch is against 4.18-rc3 (localversion-next is next-20180709)

arch/microblaze/pci/xilinx_pci.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/microblaze/pci/xilinx_pci.c b/arch/microblaze/pci/xilinx_pci.c
index 14c7da5f..7fa72ff 100644
--- a/arch/microblaze/pci/xilinx_pci.c
+++ b/arch/microblaze/pci/xilinx_pci.c
@@ -157,6 +157,7 @@ void __init xilinx_pci_init(void)

/* Set the max bus number to 255, and bus/subbus no's to 0 */
pci_reg = of_iomap(pci_node, 0);
+ WARN_ON(!pci_reg);
out_be32(pci_reg + XPLB_PCI_BUS, 0x000000ff);
iounmap(pci_reg);

--
2.1.4



2018-07-11 08:08:08

by Michal Simek

[permalink] [raw]
Subject: Re: [PATCH] microblaze: warn if of_iomap() failed

On 9.7.2018 10:42, Nicholas Mc Guire wrote:
> of_iomap() can return NULL. The function is void thus error propagation
> is not possible but at least a WARN_ON() seems warranted here as a silent
> failure might lead to a hard to understand system state.
>
> Signed-off-by: Nicholas Mc Guire <[email protected]>
> ---
>
> Problem located with experimental coccinelle script
>
> Probably this should be a BUG_ON() as this is such a low level fault that
> continuing operations probably makes little sense.
>
> Patch was compiletested with: mmu_defconfig (implies CONFIG_PCI_XILINX=y)
>
> Patch is against 4.18-rc3 (localversion-next is next-20180709)
>
> arch/microblaze/pci/xilinx_pci.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/microblaze/pci/xilinx_pci.c b/arch/microblaze/pci/xilinx_pci.c
> index 14c7da5f..7fa72ff 100644
> --- a/arch/microblaze/pci/xilinx_pci.c
> +++ b/arch/microblaze/pci/xilinx_pci.c
> @@ -157,6 +157,7 @@ void __init xilinx_pci_init(void)
>
> /* Set the max bus number to 255, and bus/subbus no's to 0 */
> pci_reg = of_iomap(pci_node, 0);
> + WARN_ON(!pci_reg);
> out_be32(pci_reg + XPLB_PCI_BUS, 0x000000ff);
> iounmap(pci_reg);
>
>

Applied.

Thanks,
Michal

--
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: http://www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP SoCs



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