diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c index ecc02a427b92..376486be3f55 100644 --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -104,10 +104,13 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, if (block->sg_table) { unsigned long flags; - sgl = block->sg_table->sgl; - nents = sg_nents_for_len(sgl, block->bytes_used); - if (nents < 0) - return nents; + /* + * Only the first sgt->nents entries carry a valid + * sg_dma_address()/sg_dma_len() pair as mapping the table may + * have coalesced entries, in which case nents is smaller than + * orig_nents. + */ + nents = block->sg_table->nents; vecs = kmalloc_array(nents, sizeof(*vecs), GFP_ATOMIC); if (!vecs) @@ -115,7 +118,8 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, len_total = block->bytes_used; - for (i = 0; i < nents; i++) { + sgl = block->sg_table->sgl; + for (i = 0; i < nents && len_total; i++) { vecs[i].addr = sg_dma_address(sgl); vecs[i].len = min(sg_dma_len(sgl), len_total); len_total -= vecs[i].len; @@ -123,6 +127,8 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, sgl = sg_next(sgl); } + nents = i; + if (block->cyclic) flags = DMA_PREP_REPEAT; else