-----Original Message----- From: kernel test robot <lkp(a)intel.com&gt; Sent: Wednesday, February 17, 2021 6:21 PM To: Lars-Peter Clausen <lars(a)metafoo.de&gt; Cc: kbuild-all(a)lists.01.org; Jonathan Cameron <Jonathan.Cameron(a)huawei.com&gt;; Ardelean, Alexandru <alexandru.Ardelean(a)analog.com&gt; Subject: [iio:testing 47/53] drivers/iio/buffer/industrialio-buffer-dma.c:669 iio_dma_buffer_alloc_blocks() warn: always true condition '(i >= 0) => (0- u32max >= 0)' [External] tree: https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/g... 23/iio.git__;!!A3Ni8CS0y2Y!r0vJx0FTiLi3bS6LugAUkUV4m4kSgQvuRql4XvRJBxLk EhqwktjO1ekJmXEVppxQ7ZPMsA$ testing head: 0fd146b288591a8139220fec417dfc5652820480 commit: b9ad66ba4db6f349aa795ed59c3e42d4208844fa [47/53] iio: buffer- dma: Add mmap support config: x86_64-randconfig-m001-20210215 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; smatch warnings: drivers/iio/buffer/industrialio-buffer-dma.c:669 iio_dma_buffer_alloc_blocks() warn: always true condition '(i >= 0) => (0-u32max >= 0)' drivers/iio/buffer/industrialio-buffer-dma.c:669 iio_dma_buffer_alloc_blocks() warn: always true condition '(i >= 0) => (0-u32max >= 0)' vim +669 drivers/iio/buffer/industrialio-buffer-dma.c 603 604 int iio_dma_buffer_alloc_blocks(struct iio_buffer *buffer, 605 struct iio_buffer_block_alloc_req *req) 606 { 607 struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); 608 struct iio_dma_buffer_block **blocks; 609 unsigned int num_blocks; 610 unsigned int i; 611 int ret = 0; 612 613 mutex_lock(&queue->lock); 614 615 /* 616 * If the buffer is enabled and in fileio mode new blocks can't be 617 * allocated. 618 */ 619 if (queue->fileio.enabled) { 620 ret = -EBUSY; 621 goto err_unlock; 622 } 623 624 /* Free memory that might be in use for fileio mode */ 625 iio_dma_buffer_fileio_free(queue); 626 627 /* 64 blocks ought to be enough for anybody ;) */ 628 if (req->count > 64 - queue->num_blocks) 629 req->count = 64 - queue->num_blocks; 630 if (req->size > iio_dma_buffer_max_block_size) 631 req->size = iio_dma_buffer_max_block_size; 632 633 req->id = queue->num_blocks; 634 635 if (req->count == 0 || req->size == 0) { 636 ret = 0; 637 goto err_unlock; 638 } 639 640 num_blocks = req->count + queue->num_blocks; 641 642 blocks = krealloc(queue->blocks, sizeof(*blocks) * num_blocks, 643 GFP_KERNEL); 644 if (!blocks) { 645 ret = -ENOMEM; 646 goto err_unlock; 647 } 648 649 for (i = queue->num_blocks; i < num_blocks; i++) { 650 blocks[i] = iio_dma_buffer_alloc_block(queue, req- >size); 651 if (!blocks[i]) { 652 ret = -ENOMEM; 653 goto err_unwind; 654 } 655 blocks[i]->block.id = i; 656 blocks[i]->block.data.offset = queue->max_offset; 657 queue->max_offset += PAGE_ALIGN(req->size); 658 } 659 660 req->count = i - queue->num_blocks; 661 queue->num_blocks = i; 662 queue->blocks = blocks; 663 664 mutex_unlock(&queue->lock); 665 666 return 0; 667 668 err_unwind: > 669 for (; i >= 0; i--)