From: Ming Lei Date: Tue, 18 Jun 2019 01:37:45 +0000 (+0800) Subject: scsi: mvumi: use sg helper to iterate over scatterlist X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3c1a30df6d9c21c3235b6af5f25da2765b19d05b;p=linux.git scsi: mvumi: use sg helper to iterate over scatterlist Unlike the legacy I/O path, scsi-mq preallocates a large array to hold the scatterlist for each request. This static allocation can consume substantial amounts of memory on modern controllers which support a large number of concurrently outstanding requests. To facilitate a switch to a smaller static allocation combined with a dynamic allocation for requests that need it, we need to make sure all SCSI drivers handle chained scatterlists correctly. Convert remaining drivers that directly dereference the scatterlist array to using the iterator functions. [mkp: clarified commit message and folded in build fix reported by zeroday] Reviewed-by: Christoph Hellwig Reviewed-by: Bart Van Assche Reviewed-by: Ewan D. Milne Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c index a5410615edacf..53f3563aca222 100644 --- a/drivers/scsi/mvumi.c +++ b/drivers/scsi/mvumi.c @@ -211,23 +211,22 @@ static int mvumi_make_sgl(struct mvumi_hba *mhba, struct scsi_cmnd *scmd, unsigned int sgnum = scsi_sg_count(scmd); dma_addr_t busaddr; - sg = scsi_sglist(scmd); - *sg_count = dma_map_sg(&mhba->pdev->dev, sg, sgnum, + *sg_count = dma_map_sg(&mhba->pdev->dev, scsi_sglist(scmd), sgnum, scmd->sc_data_direction); if (*sg_count > mhba->max_sge) { dev_err(&mhba->pdev->dev, "sg count[0x%x] is bigger than max sg[0x%x].\n", *sg_count, mhba->max_sge); - dma_unmap_sg(&mhba->pdev->dev, sg, sgnum, + dma_unmap_sg(&mhba->pdev->dev, scsi_sglist(scmd), sgnum, scmd->sc_data_direction); return -1; } - for (i = 0; i < *sg_count; i++) { - busaddr = sg_dma_address(&sg[i]); + scsi_for_each_sg(scmd, sg, *sg_count, i) { + busaddr = sg_dma_address(sg); m_sg->baseaddr_l = cpu_to_le32(lower_32_bits(busaddr)); m_sg->baseaddr_h = cpu_to_le32(upper_32_bits(busaddr)); m_sg->flags = 0; - sgd_setsz(mhba, m_sg, cpu_to_le32(sg_dma_len(&sg[i]))); + sgd_setsz(mhba, m_sg, cpu_to_le32(sg_dma_len(sg))); if ((i + 1) == *sg_count) m_sg->flags |= 1U << mhba->eot_flag;