Re: [PATCH v2 1/6] iio: introduce IIO_DECLARE_BUFFER_WITH_TS macros

[kernel test robot <lkp@intel.com>]

Hi David,

kernel test robot noticed the following build errors:

[auto build test ERROR on aff301f37e220970c2f301b5c65a8bfedf52058e]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Lechner/iio-introduce-IIO_DECLARE_BUFFER_WITH_TS-macros/20250423-061049
base:   aff301f37e220970c2f301b5c65a8bfedf52058e
patch link:    https://lore.kernel.org/r/20250422-iio-introduce-iio_declare_buffer_with_ts-v2-1-3fd36475c706%40baylibre.com
patch subject: [PATCH v2 1/6] iio: introduce IIO_DECLARE_BUFFER_WITH_TS macros
config: riscv-randconfig-002-20250424 (https://download.01.org/0day-ci/archive/20250424/202504240137.4mJaj0GN-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250424/202504240137.4mJaj0GN-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504240137.4mJaj0GN-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:804:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     804 |         insb(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:104:53: note: expanded from macro 'insb'
     104 | #define insb(addr, buffer, count) __insb(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:812:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     812 |         insw(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:105:53: note: expanded from macro 'insw'
     105 | #define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:820:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     820 |         insl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:106:53: note: expanded from macro 'insl'
     106 | #define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:829:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     829 |         outsb(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:118:55: note: expanded from macro 'outsb'
     118 | #define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:838:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     838 |         outsw(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:119:55: note: expanded from macro 'outsw'
     119 | #define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:847:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     847 |         outsl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:120:55: note: expanded from macro 'outsl'
     120 | #define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:18:
   In file included from include/linux/dma-buf.h:16:
   In file included from include/linux/iosys-map.h:10:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:1175:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
    1175 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
         |                                                   ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-buffer.c:29:
>> include/linux/iio/iio.h:813:16: error: static assertion failed due to requirement 'sizeof (__alignof(unsigned long long)) % sizeof(long long) == 0': macros above assume that IIO_DMA_MINALIGN also ensures s64 timestamp alignment
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/iio/iio.h:813:55: note: expression evaluates to '4 == 0'
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
   7 warnings and 1 error generated.
--
   In file included from drivers/iio/industrialio-sw-device.c:14:
   In file included from include/linux/iio/sw_device.h:13:
>> include/linux/iio/iio.h:813:16: error: static assertion failed due to requirement 'sizeof (__alignof(unsigned long long)) % sizeof(long long) == 0': macros above assume that IIO_DMA_MINALIGN also ensures s64 timestamp alignment
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/iio/iio.h:813:55: note: expression evaluates to '4 == 0'
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
   1 error generated.
--
   In file included from drivers/iio/industrialio-triggered-event.c:9:
>> include/linux/iio/iio.h:813:16: error: static assertion failed due to requirement 'sizeof (__alignof(unsigned long long)) % sizeof(long long) == 0': macros above assume that IIO_DMA_MINALIGN also ensures s64 timestamp alignment
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/iio/iio.h:813:55: note: expression evaluates to '4 == 0'
     813 | _Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
         |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:804:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     804 |         insb(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:104:53: note: expanded from macro 'insb'
     104 | #define insb(addr, buffer, count) __insb(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:812:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     812 |         insw(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:105:53: note: expanded from macro 'insw'
     105 | #define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:820:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     820 |         insl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:106:53: note: expanded from macro 'insl'
     106 | #define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:829:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     829 |         outsb(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:118:55: note: expanded from macro 'outsb'
     118 | #define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:838:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     838 |         outsw(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:119:55: note: expanded from macro 'outsw'
     119 | #define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   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:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:847:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     847 |         outsl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:120:55: note: expanded from macro 'outsl'
     120 | #define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/industrialio-triggered-event.c:10:
   In file included from include/linux/iio/triggered_event.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:


vim +813 include/linux/iio/iio.h

   781	
   782	#define _IIO_DECLARE_BUFFER_WITH_TS(type, name, count) \
   783		type name[ALIGN((count), sizeof(s64) / sizeof(type)) + sizeof(s64) / sizeof(type)]
   784	
   785	/**
   786	 * IIO_DECLARE_BUFFER_WITH_TS() - Declare a buffer with timestamp
   787	 * @type: element type of the buffer
   788	 * @name: identifier name of the buffer
   789	 * @count: number of elements in the buffer
   790	 *
   791	 * Declares a buffer that is safe to use with iio_push_to_buffer_with_ts(). In
   792	 * addition to allocating enough space for @count elements of @type, it also
   793	 * allocates space for a s64 timestamp at the end of the buffer and ensures
   794	 * proper alignment of the timestamp.
   795	 */
   796	#define IIO_DECLARE_BUFFER_WITH_TS(type, name, count) \
   797		_IIO_DECLARE_BUFFER_WITH_TS(type, name, count) __aligned(sizeof(s64))
   798	
   799	/**
   800	 * IIO_DECLARE_DMA_BUFFER_WITH_TS() - Declare a DMA-aligned buffer with timestamp
   801	 * @type: element type of the buffer
   802	 * @name: identifier name of the buffer
   803	 * @count: number of elements in the buffer
   804	 *
   805	 * Same as IIO_DECLARE_BUFFER_WITH_TS(), but is uses __aligned(IIO_DMA_MINALIGN)
   806	 * to ensure that the buffer doesn't share cachelines with anything that comes
   807	 * before it in a struct. This should not be used for stack-allocated buffers
   808	 * as stack memory cannot generally be used for DMA.
   809	 */
   810	#define IIO_DECLARE_DMA_BUFFER_WITH_TS(type, name, count) \
   811		_IIO_DECLARE_BUFFER_WITH_TS(type, name, count) __aligned(IIO_DMA_MINALIGN)
   812	
 > 813	_Static_assert(sizeof(IIO_DMA_MINALIGN) % sizeof(s64) == 0,
   814		"macros above assume that IIO_DMA_MINALIGN also ensures s64 timestamp alignment");
   815	

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