RE: [PATCH] dma-mapping: fix dma_addressing_limited if dma_range_map is scanned

[Justin He]

> -----Original Message-----
> From: kernel test robot <lkp@xxxxxxxxx>
> Sent: Wednesday, September 13, 2023 2:28 AM
> To: Justin He <Justin.He@xxxxxxx>; Christoph Hellwig <hch@xxxxxx>; Marek
> Szyprowski <m.szyprowski@xxxxxxxxxxx>; Robin Murphy
> <Robin.Murphy@xxxxxxx>; iommu@xxxxxxxxxxxxxxx
> Cc: llvm@xxxxxxxxxxxxxxx; oe-kbuild-all@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Justin He <Justin.He@xxxxxxx>
> Subject: Re: [PATCH] dma-mapping: fix dma_addressing_limited if
> dma_range_map is scanned
> 
> Hi Jia,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v6.6-rc1 next-20230912] [If your patch is applied to
> the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:
> https://github.com/intel-lab-lkp/linux/commits/Jia-He/dma-mapping-fix-dma_
> addressing_limited-if-dma_range_map-is-scanned/20230912-164126
> base:   linus/master
> patch link:
> https://lore.kernel.org/r/20230912084002.2168-1-justin.he%40arm.com
> patch subject: [PATCH] dma-mapping: fix dma_addressing_limited if
> dma_range_map is scanned
> config: um-allyesconfig
> (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9
> W-lkp@xxxxxxxxx/config)
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git
> f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce (this is a W=1 build):
> (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9
> W-lkp@xxxxxxxxx/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes:
> | https://lore.kernel.org/oe-kbuild-all/202309130234.COIfUg9W-lkp@intel.
> | com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from init/main.c:102:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
Seems I need to define a stub when DMA Kconfig is disabled.
Thanks

--
Cheers,
Justin (Jia He)

>                    ^
>    12 warnings and 1 error generated.
> --
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    arch/um/os-Linux/drivers/ethertap_kern.c:66:5: warning: no previous
> prototype for function 'ethertap_setup' [-Wmissing-prototypes]
>    int ethertap_setup(char *str, char **mac_out, void *data)
>        ^
>    arch/um/os-Linux/drivers/ethertap_kern.c:66:1: note: declare 'static' if the
> function is not intended to be used outside of this translation unit
>    int ethertap_setup(char *str, char **mac_out, void *data)
>    ^
>    static
>    13 warnings and 1 error generated.
> --
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    arch/um/os-Linux/drivers/tuntap_kern.c:56:5: warning: no previous
> prototype for function 'tuntap_setup' [-Wmissing-prototypes]
>    int tuntap_setup(char *str, char **mac_out, void *data)
>        ^
>    arch/um/os-Linux/drivers/tuntap_kern.c:56:1: note: declare 'static' if the
> function is not intended to be used outside of this translation unit
>    int tuntap_setup(char *str, char **mac_out, void *data)
>    ^
>    static
>    13 warnings and 1 error generated.
> --
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from net/ipv4/route.c:71:
>    In file included from include/linux/inet.h:42:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    net/ipv4/route.c:880:6: warning: variable 'log_martians' set but not used
> [-Wunused-but-set-variable]
>            int log_martians;
>                ^
>    13 warnings and 1 error generated.
> ..
> 
> 
> vim +/all_ram_in_dma_range_map +483 include/linux/dma-mapping.h
> 
>    468
>    469	/**
>    470	 * dma_addressing_limited - return if the device is addressing
> limited
>    471	 * @dev:	device to check
>    472	 *
>    473	 * Return %true if the devices DMA mask is too small to address all
> memory in
>    474	 * the system, else %false.  Lack of addressing bits is the prime
> reason for
>    475	 * bounce buffering, but might not be the only one.
>    476	 */
>    477	static inline bool dma_addressing_limited(struct device *dev)
>    478	{
>    479		if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
>    480							dma_get_required_mask(dev))
>    481			return true;
>    482
>  > 483		return !all_ram_in_dma_range_map(dev);
>    484	}
>    485
> 
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki