Hi, Christoph Hellwig <hch@xxxxxxxxxxxxx> writes: > On Thu, Feb 06, 2020 at 08:29:45PM +0200, Felipe Balbi wrote: >> Fair enough. Just out of curiosity, then, when *should* we use >> sg_is_last()? > > Outside of sg_next/sg_last it really shoud not be used at all as far > as I'm concerned. In that case, we may have other drivers with similar issues that just haven't surfaced: $ git --no-pager grep -e sg_is_last drivers/ata/pata_octeon_cf.c:701: if (!sg_is_last(qc->cursg)) { drivers/crypto/amcc/crypto4xx_core.c:738: if (sg_is_last(dst) && force_sd == false) { drivers/crypto/atmel-sha.c:318: if ((ctx->sg->length == 0) && !sg_is_last(ctx->sg)) { drivers/crypto/atmel-sha.c:781: if (!sg_is_last(sg) && !IS_ALIGNED(sg->length, ctx->block_size)) drivers/crypto/atmel-sha.c:787: if (sg_is_last(sg)) { drivers/crypto/ccree/cc_buffer_mgr.c:293: if (sg_is_last(sg)) { drivers/crypto/ccree/cc_buffer_mgr.c:305: } else { /*sg_is_last*/ drivers/crypto/hisilicon/hpre/hpre_crypto.c:238: if ((sg_is_last(data) && len == ctx->key_sz) && drivers/crypto/marvell/tdma.c:25: if (sg_is_last(sgiter->sg)) drivers/crypto/mediatek/mtk-sha.c:196: if ((ctx->sg->length == 0) && !sg_is_last(ctx->sg)) { drivers/crypto/mediatek/mtk-sha.c:530: if (!sg_is_last(sg) && !IS_ALIGNED(sg->length, ctx->bs)) drivers/crypto/mediatek/mtk-sha.c:536: if (sg_is_last(sg)) { drivers/crypto/mxs-dcp.c:339: if (actx->fill == out_off || sg_is_last(src) || drivers/crypto/qat/qat_common/qat_asym_algs.c:322: if (sg_is_last(req->src) && req->src_len == ctx->p_size) { drivers/crypto/qat/qat_common/qat_asym_algs.c:353: if (sg_is_last(req->dst) && req->dst_len == ctx->p_size) { drivers/crypto/qat/qat_common/qat_asym_algs.c:730: if (sg_is_last(req->src) && req->src_len == ctx->key_sz) { drivers/crypto/qat/qat_common/qat_asym_algs.c:749: if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) { drivers/crypto/qat/qat_common/qat_asym_algs.c:874: if (sg_is_last(req->src) && req->src_len == ctx->key_sz) { drivers/crypto/qat/qat_common/qat_asym_algs.c:893: if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) { drivers/crypto/rockchip/rk3288_crypto_ahash.c:238: if (sg_is_last(dev->sg_src)) { drivers/crypto/rockchip/rk3288_crypto_skcipher.c:356: if (sg_is_last(dev->sg_src)) { drivers/crypto/s5p-sss.c:581: if (!sg_is_last(dev->sg_dst)) { drivers/crypto/s5p-sss.c:603: if (!sg_is_last(dev->sg_src)) { drivers/crypto/s5p-sss.c:690: if (sg_is_last(dev->sg_dst)) drivers/crypto/stm32/stm32-hash.c:304: if ((rctx->sg->length == 0) && !sg_is_last(rctx->sg)) { drivers/crypto/stm32/stm32-hash.c:568: if (sg_is_last(sg)) { drivers/crypto/stm32/stm32-hash.c:595: !sg_is_last(sg)); drivers/crypto/stm32/stm32-hash.c:668: (!sg_is_last(sg))) drivers/dma/ipu/ipu_idmac.c:847: dma_addr_t dma_1 = sg_is_last(desc->sg) ? 0 : drivers/gpu/drm/i915/i915_gpu_error.c:649: if (sg_is_last(sg)) drivers/gpu/drm/i915/i915_gpu_error.c:653: sg = sg_is_last(sg) ? NULL : sg_chain_ptr(sg); drivers/gpu/drm/i915/i915_gpu_error.c:903: } while (!sg_is_last(sg++)); drivers/gpu/drm/i915/i915_scatterlist.h:66: return sg_is_last(sg) ? NULL : ____sg_next(sg); drivers/hwtracing/intel_th/msu.c:545: if (sg_is_last(iter->block)) drivers/memstick/core/ms_block.c:43: if (sg_is_last(sg_from)) drivers/memstick/core/ms_block.c:58: if (sg_is_last(sg_from) || !len) drivers/memstick/core/ms_block.c:73: if (sg_is_last(sg_from) || !len) drivers/mmc/host/bcm2835.c:485: if (sg_is_last(sg)) { drivers/rapidio/devices/tsi721_dma.c:514: if (sg_is_last(sg)) { drivers/s390/scsi/zfcp_qdio.h:184: return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN; drivers/scsi/NCR5380.c:171: if (!cmd->SCp.this_residual && s && !sg_is_last(s)) { drivers/scsi/NCR5380.c:184: while (!sg_is_last(s)) { drivers/scsi/aha152x.c:2019: !sg_is_last(CURRENT_SC->SCp.buffer)) { drivers/scsi/aha152x.c:2125: !sg_is_last(CURRENT_SC->SCp.buffer)) { drivers/scsi/aha152x.c:2155: while (done > 0 && !sg_is_last(sg)) { drivers/scsi/qla2xxx/qla_iocb.c:1226: sg_is_last(sg)) { drivers/spi/spi-bcm2835.c:484: if (bs->tx_buf && !sg_is_last(&tfr->tx_sg.sgl[0])) drivers/spi/spi-bcm2835.c:487: if (bs->rx_buf && !sg_is_last(&tfr->rx_sg.sgl[0])) { drivers/spi/spi-bcm2835.c:491: if (!bs->tx_buf || sg_is_last(&tfr->tx_sg.sgl[0])) { drivers/usb/dwc2/gadget.c:861: sg_is_last(sg)); drivers/usb/dwc3/gadget.c:1074: if (sg_is_last(s)) drivers/usb/image/microtek.c:507: sg_is_last(context->curr_sg) ? include/linux/devcoredump.h:40: while (!sg_is_last(iter)) { include/linux/scatterlist.h:73:#define sg_is_last(sg) ((sg)->page_link & SG_END) lib/scatterlist.c:25: if (sg_is_last(sg)) lib/scatterlist.c:109: BUG_ON(!sg_is_last(ret)); net/core/skbuff.c:4289: if (unlikely(elt && sg_is_last(&sg[elt - 1]))) net/core/skbuff.c:4311: if (unlikely(elt && sg_is_last(&sg[elt - 1]))) net/tls/tls_main.c:116: if (sg_is_last(sg)) net/xfrm/espintcp.c:179: if (sg_is_last(sg)) samples/kfifo/dma-example.c:79: if (sg_is_last(&sg[i])) samples/kfifo/dma-example.c:108: if (sg_is_last(&sg[i])) tools/virtio/linux/scatterlist.h:15:#define sg_is_last(sg) ((sg)->page_link & 0x02) tools/virtio/linux/scatterlist.h:139: if (sg_is_last(sg)) -- balbi
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