tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable head: 2d9bfd745d675f50d81466645e10fde77e75eea9 commit: a6be92e5510c1505cad39d7b707f78b70eb98725 [30/33] kfifo: introduce and use kfifo_skip_count() config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20240225/202402250254.ZU9AWM30-lkp@xxxxxxxxx/config) compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240225/202402250254.ZU9AWM30-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/202402250254.ZU9AWM30-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> samples/kfifo/dma-example.c:119:2: warning: variable '__tmp' is uninitialized when used within its own initialization [-Wuninitialized] 119 | kfifo_dma_out_finish(&fifo, ret); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kfifo.h:801:19: note: expanded from macro 'kfifo_dma_out_finish' 801 | kfifo_skip_count(__tmp, (len) / sizeof(*__tmp->type)); \ | ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kfifo.h:312:30: note: expanded from macro 'kfifo_skip_count' 312 | typeof((fifo) + 1) __tmp = (fifo); \ | ~~~~~ ^~~~ 1 warning generated. vim +/__tmp +119 samples/kfifo/dma-example.c 5bf2b19320ec31 Stefani Seibold 2010-08-10 20 5bf2b19320ec31 Stefani Seibold 2010-08-10 21 static int __init example_init(void) 5bf2b19320ec31 Stefani Seibold 2010-08-10 22 { 5bf2b19320ec31 Stefani Seibold 2010-08-10 23 int i; 5bf2b19320ec31 Stefani Seibold 2010-08-10 24 unsigned int ret; 399f1e30ac17b7 Ira W. Snyder 2010-09-30 25 unsigned int nents; 5bf2b19320ec31 Stefani Seibold 2010-08-10 26 struct scatterlist sg[10]; 5bf2b19320ec31 Stefani Seibold 2010-08-10 27 5bf2b19320ec31 Stefani Seibold 2010-08-10 28 printk(KERN_INFO "DMA fifo test start\n"); 5bf2b19320ec31 Stefani Seibold 2010-08-10 29 5bf2b19320ec31 Stefani Seibold 2010-08-10 30 if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) { a25effa4d265eb Andrea Righi 2010-08-19 31 printk(KERN_WARNING "error kfifo_alloc\n"); a25effa4d265eb Andrea Righi 2010-08-19 32 return -ENOMEM; 5bf2b19320ec31 Stefani Seibold 2010-08-10 33 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 34 5bf2b19320ec31 Stefani Seibold 2010-08-10 35 printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo)); 5bf2b19320ec31 Stefani Seibold 2010-08-10 36 5bf2b19320ec31 Stefani Seibold 2010-08-10 37 kfifo_in(&fifo, "test", 4); 5bf2b19320ec31 Stefani Seibold 2010-08-10 38 5bf2b19320ec31 Stefani Seibold 2010-08-10 39 for (i = 0; i != 9; i++) 498d319bb51299 Stefani Seibold 2013-11-14 40 kfifo_put(&fifo, i); 5bf2b19320ec31 Stefani Seibold 2010-08-10 41 5bf2b19320ec31 Stefani Seibold 2010-08-10 42 /* kick away first byte */ a25effa4d265eb Andrea Righi 2010-08-19 43 kfifo_skip(&fifo); 5bf2b19320ec31 Stefani Seibold 2010-08-10 44 5bf2b19320ec31 Stefani Seibold 2010-08-10 45 printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); 5bf2b19320ec31 Stefani Seibold 2010-08-10 46 a25effa4d265eb Andrea Righi 2010-08-19 47 /* a25effa4d265eb Andrea Righi 2010-08-19 48 * Configure the kfifo buffer to receive data from DMA input. a25effa4d265eb Andrea Righi 2010-08-19 49 * a25effa4d265eb Andrea Righi 2010-08-19 50 * .--------------------------------------. a25effa4d265eb Andrea Righi 2010-08-19 51 * | 0 | 1 | 2 | ... | 12 | 13 | ... | 31 | a25effa4d265eb Andrea Righi 2010-08-19 52 * |---|------------------|---------------| a25effa4d265eb Andrea Righi 2010-08-19 53 * \_/ \________________/ \_____________/ a25effa4d265eb Andrea Righi 2010-08-19 54 * \ \ \ a25effa4d265eb Andrea Righi 2010-08-19 55 * \ \_allocated data \ a25effa4d265eb Andrea Righi 2010-08-19 56 * \_*free space* \_*free space* a25effa4d265eb Andrea Righi 2010-08-19 57 * a25effa4d265eb Andrea Righi 2010-08-19 58 * We need two different SG entries: one for the free space area at the a25effa4d265eb Andrea Righi 2010-08-19 59 * end of the kfifo buffer (19 bytes) and another for the first free a25effa4d265eb Andrea Righi 2010-08-19 60 * byte at the beginning, after the kfifo_skip(). a25effa4d265eb Andrea Righi 2010-08-19 61 */ 7b34d5257a90c4 Andrea Righi 2010-08-19 62 sg_init_table(sg, ARRAY_SIZE(sg)); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 63 nents = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 64 printk(KERN_INFO "DMA sgl entries: %d\n", nents); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 65 if (!nents) { a25effa4d265eb Andrea Righi 2010-08-19 66 /* fifo is full and no sgl was created */ a25effa4d265eb Andrea Righi 2010-08-19 67 printk(KERN_WARNING "error kfifo_dma_in_prepare\n"); a25effa4d265eb Andrea Righi 2010-08-19 68 return -EIO; a25effa4d265eb Andrea Righi 2010-08-19 69 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 70 a25effa4d265eb Andrea Righi 2010-08-19 71 /* receive data */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 72 printk(KERN_INFO "scatterlist for receive:\n"); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 73 for (i = 0; i < nents; i++) { 5bf2b19320ec31 Stefani Seibold 2010-08-10 74 printk(KERN_INFO 5bf2b19320ec31 Stefani Seibold 2010-08-10 75 "sg[%d] -> " 9263969a46fc89 Logan Gunthorpe 2017-07-12 76 "page %p offset 0x%.8x length 0x%.8x\n", 9263969a46fc89 Logan Gunthorpe 2017-07-12 77 i, sg_page(&sg[i]), sg[i].offset, sg[i].length); 5bf2b19320ec31 Stefani Seibold 2010-08-10 78 5bf2b19320ec31 Stefani Seibold 2010-08-10 79 if (sg_is_last(&sg[i])) 5bf2b19320ec31 Stefani Seibold 2010-08-10 80 break; 5bf2b19320ec31 Stefani Seibold 2010-08-10 81 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 82 a25effa4d265eb Andrea Righi 2010-08-19 83 /* put here your code to setup and exectute the dma operation */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 84 /* ... */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 85 5bf2b19320ec31 Stefani Seibold 2010-08-10 86 /* example: zero bytes received */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 87 ret = 0; 5bf2b19320ec31 Stefani Seibold 2010-08-10 88 5bf2b19320ec31 Stefani Seibold 2010-08-10 89 /* finish the dma operation and update the received data */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 90 kfifo_dma_in_finish(&fifo, ret); 5bf2b19320ec31 Stefani Seibold 2010-08-10 91 a25effa4d265eb Andrea Righi 2010-08-19 92 /* Prepare to transmit data, example: 8 bytes */ 399f1e30ac17b7 Ira W. Snyder 2010-09-30 93 nents = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 94 printk(KERN_INFO "DMA sgl entries: %d\n", nents); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 95 if (!nents) { a25effa4d265eb Andrea Righi 2010-08-19 96 /* no data was available and no sgl was created */ a25effa4d265eb Andrea Righi 2010-08-19 97 printk(KERN_WARNING "error kfifo_dma_out_prepare\n"); a25effa4d265eb Andrea Righi 2010-08-19 98 return -EIO; a25effa4d265eb Andrea Righi 2010-08-19 99 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 100 5bf2b19320ec31 Stefani Seibold 2010-08-10 101 printk(KERN_INFO "scatterlist for transmit:\n"); 399f1e30ac17b7 Ira W. Snyder 2010-09-30 102 for (i = 0; i < nents; i++) { 5bf2b19320ec31 Stefani Seibold 2010-08-10 103 printk(KERN_INFO 5bf2b19320ec31 Stefani Seibold 2010-08-10 104 "sg[%d] -> " 9263969a46fc89 Logan Gunthorpe 2017-07-12 105 "page %p offset 0x%.8x length 0x%.8x\n", 9263969a46fc89 Logan Gunthorpe 2017-07-12 106 i, sg_page(&sg[i]), sg[i].offset, sg[i].length); 5bf2b19320ec31 Stefani Seibold 2010-08-10 107 5bf2b19320ec31 Stefani Seibold 2010-08-10 108 if (sg_is_last(&sg[i])) 5bf2b19320ec31 Stefani Seibold 2010-08-10 109 break; 5bf2b19320ec31 Stefani Seibold 2010-08-10 110 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 111 a25effa4d265eb Andrea Righi 2010-08-19 112 /* put here your code to setup and exectute the dma operation */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 113 /* ... */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 114 5bf2b19320ec31 Stefani Seibold 2010-08-10 115 /* example: 5 bytes transmitted */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 116 ret = 5; 5bf2b19320ec31 Stefani Seibold 2010-08-10 117 5bf2b19320ec31 Stefani Seibold 2010-08-10 118 /* finish the dma operation and update the transmitted data */ 5bf2b19320ec31 Stefani Seibold 2010-08-10 @119 kfifo_dma_out_finish(&fifo, ret); 5bf2b19320ec31 Stefani Seibold 2010-08-10 120 a25effa4d265eb Andrea Righi 2010-08-19 121 ret = kfifo_len(&fifo); 5bf2b19320ec31 Stefani Seibold 2010-08-10 122 printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); 5bf2b19320ec31 Stefani Seibold 2010-08-10 123 a25effa4d265eb Andrea Righi 2010-08-19 124 if (ret != 7) { a25effa4d265eb Andrea Righi 2010-08-19 125 printk(KERN_WARNING "size mismatch: test failed"); a25effa4d265eb Andrea Righi 2010-08-19 126 return -EIO; a25effa4d265eb Andrea Righi 2010-08-19 127 } a25effa4d265eb Andrea Righi 2010-08-19 128 printk(KERN_INFO "test passed\n"); a25effa4d265eb Andrea Righi 2010-08-19 129 5bf2b19320ec31 Stefani Seibold 2010-08-10 130 return 0; 5bf2b19320ec31 Stefani Seibold 2010-08-10 131 } 5bf2b19320ec31 Stefani Seibold 2010-08-10 132 :::::: The code at line 119 was first introduced by commit :::::: 5bf2b19320ec31d094d7370fdf536f7fd91fd799 kfifo: add example files to the kernel sample directory :::::: TO: Stefani Seibold <stefani@xxxxxxxxxxx> :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
