From: 'Christoph Hellwig' <hch@lst.de>
To: David Laight <David.Laight@ACULAB.COM>
Cc: 'Christoph Hellwig' <hch@lst.de>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>, Baoquan He <bhe@redhat.com>,
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Subject: Re: [PATCH 22/22] mtd: rawnand: Use dma_alloc_noncoherent() for dma buffer
Date: Tue, 22 Feb 2022 14:16:10 +0100 [thread overview]
Message-ID: <20220222131610.GA10464@lst.de> (raw)
In-Reply-To: <fe8deb6dd0b44a8a839820747451c37c@AcuMS.aculab.com>
On Tue, Feb 22, 2022 at 09:06:48AM +0000, David Laight wrote:
> From: Christoph Hellwig
> > Sent: 22 February 2022 08:47
> ...
> > > Hmm.. for this specific case, What about allocating two buffers
> > > for DMA_TO_DEVICE and DMA_FROM_DEVICE at initialization time?
> >
> > That will work, but I don't see the benefit as you'd still need to call
> > dma_sync_single* before and after each data transfer.
>
> For systems with an iommu that should save all the iommu setup
> for every transfer.
So does allocating a single buffer as in the patch we are replying to.
next prev parent reply other threads:[~2022-02-22 13:16 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-19 0:51 [PATCH 00/22] Don't use kmalloc() with GFP_DMA Baoquan He
2022-02-19 0:52 ` [PATCH 01/22] parisc: pci-dma: remove stale code and comment Baoquan He
2022-02-19 7:07 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 02/22] net: moxa: Don't use GFP_DMA when calling dma_alloc_coherent() Baoquan He
2022-02-19 7:07 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 03/22] gpu: ipu-v3: " Baoquan He
2022-02-19 7:07 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 04/22] drm/sti: Don't use GFP_DMA when calling dma_alloc_wc() Baoquan He
2022-02-19 7:08 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 05/22] sound: n64: Don't use GFP_DMA when calling dma_alloc_coherent() Baoquan He
2022-02-19 7:08 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 06/22] fbdev: da8xx: " Baoquan He
2022-02-19 7:08 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 07/22] fbdev: mx3fb: Don't use GFP_DMA when calling dma_alloc_wc() Baoquan He
2022-02-19 7:08 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 08/22] usb: gadget: lpc32xx_udc: Don't use GFP_DMA when calling dma_alloc_coherent() Baoquan He
2022-02-19 7:09 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 09/22] usb: cdns3: " Baoquan He
2022-02-19 7:09 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 10/22] uio: pruss: " Baoquan He
2022-02-19 7:09 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 11/22] staging: emxx_udc: " Baoquan He
2022-02-19 6:51 ` Wolfram Sang
2022-02-20 1:55 ` Baoquan He
2022-02-19 7:09 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 12/22] " Baoquan He
2022-02-19 7:10 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 13/22] spi: atmel: " Baoquan He
2022-02-19 7:10 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 14/22] spi: spi-ti-qspi: " Baoquan He
2022-02-19 7:12 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 15/22] usb: cdns3: Don't use GFP_DMA32 when calling dma_pool_alloc() Baoquan He
2022-02-19 7:13 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 16/22] usb: udc: lpc32xx: Don't use GFP_DMA " Baoquan He
2022-02-19 7:13 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 17/22] net: marvell: prestera: " Baoquan He
2022-02-19 4:54 ` Jakub Kicinski
2022-02-20 2:06 ` Baoquan He
2022-02-19 7:13 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 18/22] net: ethernet: mtk-star-emac: Don't use GFP_DMA when calling dmam_alloc_coherent() Baoquan He
2022-02-19 7:13 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 19/22] ethernet: rocker: Use dma_alloc_noncoherent() for dma buffer Baoquan He
2022-02-19 7:14 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 20/22] HID: intel-ish-hid: " Baoquan He
2022-02-19 7:14 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 21/22] mmc: wbsd: " Baoquan He
2022-02-19 7:17 ` Christoph Hellwig
2022-02-20 8:40 ` Baoquan He
2022-02-22 8:45 ` Christoph Hellwig
2022-02-22 9:14 ` Baoquan He
2022-02-22 13:11 ` Christoph Hellwig
2022-02-22 13:40 ` Baoquan He
2022-02-22 13:41 ` [PATCH 1/2] dma-mapping: check dma_mask for streaming mapping allocs Baoquan He
2022-02-22 15:59 ` Christoph Hellwig
2022-02-23 0:28 ` Baoquan He
2022-02-23 14:25 ` Christoph Hellwig
2022-02-23 14:57 ` David Laight
2022-02-24 14:11 ` Baoquan He
2022-02-24 14:27 ` David Laight
2022-02-25 15:39 ` 'Baoquan He'
2022-02-22 13:42 ` [PATCH 2/2] kernel/dma: rename dma_alloc_direct and dma_map_direct Baoquan He
2022-02-22 15:59 ` Christoph Hellwig
2022-02-19 0:52 ` [PATCH 22/22] mtd: rawnand: Use dma_alloc_noncoherent() for dma buffer Baoquan He
2022-02-19 7:19 ` Christoph Hellwig
2022-02-19 11:18 ` Hyeonggon Yoo
2022-02-22 8:46 ` Christoph Hellwig
2022-02-22 9:06 ` David Laight
2022-02-22 13:16 ` 'Christoph Hellwig' [this message]
2022-02-21 13:57 ` [PATCH 00/22] Don't use kmalloc() with GFP_DMA Heiko Carstens
2022-02-22 8:44 ` Christoph Hellwig
2022-02-22 13:12 ` Baoquan He
2022-02-22 13:26 ` Baoquan He
2022-02-23 19:18 ` Heiko Carstens
2022-02-24 6:33 ` Christoph Hellwig
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