linux-kernel - [PATCH v2 0/8] dmaengine: Add new API to combine onfiguration and descriptor preparation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251218-dma_prep_config-v2-0-c07079836128@nxp.com>
Date: Thu, 18 Dec 2025 10:56:20 -0500
From: Frank Li <Frank.Li@....com>
To: Vinod Koul <vkoul@...nel.org>, Manivannan Sadhasivam <mani@...nel.org>, 
 Krzysztof Wilczyński <kwilczynski@...nel.org>, 
 Kishon Vijay Abraham I <kishon@...nel.org>, 
 Bjorn Helgaas <bhelgaas@...gle.com>, Christoph Hellwig <hch@....de>, 
 Sagi Grimberg <sagi@...mberg.me>, Chaitanya Kulkarni <kch@...dia.com>, 
 Herbert Xu <herbert@...dor.apana.org.au>, 
 "David S. Miller" <davem@...emloft.net>, 
 Nicolas Ferre <nicolas.ferre@...rochip.com>, 
 Alexandre Belloni <alexandre.belloni@...tlin.com>, 
 Claudiu Beznea <claudiu.beznea@...on.dev>, Koichiro Den <den@...inux.co.jp>, 
 Niklas Cassel <cassel@...nel.org>
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-pci@...r.kernel.org, linux-nvme@...ts.infradead.org, 
 mhi@...ts.linux.dev, linux-arm-msm@...r.kernel.org, 
 linux-crypto@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 imx@...ts.linux.dev, Frank Li <Frank.Li@....com>
Subject: [PATCH v2 0/8] dmaengine: Add new API to combine onfiguration and
 descriptor preparation

Previously, configuration and preparation required two separate calls. This
works well when configuration is done only once during initialization.

However, in cases where the burst length or source/destination address must
be adjusted for each transfer, calling two functions is verbose.

	if (dmaengine_slave_config(chan, &sconf)) {
		dev_err(dev, "DMA slave config fail\n");
		return -EIO;
	}

	tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags);

After new API added

	tx = dmaengine_prep_config_single(chan, dma_local, len, dir, flags, &sconf);

Additional, prevous two calls requires additional locking to ensure both
steps complete atomically.

    mutex_lock()
    dmaengine_slave_config()
    dmaengine_prep_slave_single()
    mutex_unlock()

after new API added, mutex lock can be moved. See patch
     nvmet: pci-epf: Use dmaengine_prep_config_single_safe() API

Signed-off-by: Frank Li <Frank.Li@....com>
---
Changes in v2:
- Use name dmaengine_prep_config_single() and dmaengine_prep_config_sg()
- Add _safe version to avoid confuse, which needn't additional mutex.
- Update document/
- Update commit message. add () for function name. Use upcase for subject.
- Add more explain for remove lock.
- Link to v1: https://lore.kernel.org/r/20251208-dma_prep_config-v1-0-53490c5e1e2a@nxp.com

---
Frank Li (8):
      dmaengine: Add API to combine configuration and preparation (sg and single)
      PCI: endpoint: pci-epf-test: Use dmaenigne_prep_config_single() to simplify code
      dmaengine: dw-edma: Use new .device_prep_config_sg() callback
      dmaengine: dw-edma: Pass dma_slave_config to dw_edma_device_transfer()
      nvmet: pci-epf: Remove unnecessary dmaengine_terminate_sync() on each DMA transfer
      nvmet: pci-epf: Use dmaengine_prep_config_single_safe() API
      PCI: epf-mhi: Use dmaengine_prep_config_single() to simplify code
      crypto: atmel: Use dmaengine_prep_config_single() API

 Documentation/driver-api/dmaengine/client.rst |   9 +++
 drivers/crypto/atmel-aes.c                    |  10 +--
 drivers/dma/dw-edma/dw-edma-core.c            |  36 ++++++---
 drivers/nvme/target/pci-epf.c                 |  21 ++----
 drivers/pci/endpoint/functions/pci-epf-mhi.c  |  52 ++++---------
 drivers/pci/endpoint/functions/pci-epf-test.c |   8 +-
 include/linux/dmaengine.h                     | 103 ++++++++++++++++++++++++--
 7 files changed, 156 insertions(+), 83 deletions(-)
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251204-dma_prep_config-654170d245a2

Best regards,
--
Frank Li <Frank.Li@....com>