linux-mtd.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Alexander Dahl <ada@thorsis.com>
To: linux-mtd@lists.infradead.org
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
	peda@axentia.se, nicolas.ferre@microchip.com,
	alexandre.belloni@bootlin.com, claudiu.beznea@microchip.com,
	bbrezillon@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] mtd: rawnand: atmel: Unmap streaming DMA mappings
Date: Fri, 29 Jul 2022 12:59:55 +0200	[thread overview]
Message-ID: <2099405.mp5hVA6q5l@ada> (raw)
In-Reply-To: <20220728074014.145406-1-tudor.ambarus@microchip.com>

Hello Tudor,

Am Donnerstag, 28. Juli 2022, 09:40:14 CEST schrieb Tudor Ambarus:
> Every dma_map_single() call should have its dma_unmap_single() counterpart,
> because the DMA address space is a shared resource and one could render the
> machine unusable by consuming all DMA addresses.
> 
> Cc: stable@vger.kernel.org
> Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
>  drivers/mtd/nand/raw/atmel/nand-controller.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c
> b/drivers/mtd/nand/raw/atmel/nand-controller.c index
> 6ef14442c71a..330d2dafdd2d 100644
> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c
> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
> @@ -405,6 +405,7 @@ static int atmel_nand_dma_transfer(struct
> atmel_nand_controller *nc,
> 
>  	dma_async_issue_pending(nc->dmac);
>  	wait_for_completion(&finished);
> +	dma_unmap_single(nc->dev, buf_dma, len, dir);
> 
>  	return 0;

Acked-by: Alexander Dahl <ada@thorsis.com>

After studying 
https://www.kernel.org/doc/html/latest/core-api/dma-api-howto.html
this seems like the correct thing to do to me.

I was made aware of this patch in IRC, after discussing a strange lzo 
decompression and/or page reading error with Richard after upgrading from 
kernel v5.2.21-rt13 to v5.15.49-rt47.

Now testing this on top of 5.15.49-rt47 on two boards, both with Microchip 
sama5d27c 128MiB SiP and Spansion S34ML02G1 raw nand flash. Will report later.

Thanks and greets
Alex




______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

  reply	other threads:[~2022-07-29 11:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-28  7:40 [PATCH] mtd: rawnand: atmel: Unmap streaming DMA mappings Tudor Ambarus
2022-07-29 10:59 ` Alexander Dahl [this message]
2022-08-09  6:28   ` Alexander Dahl
2022-08-02 11:03 ` Tudor.Ambarus
2022-08-16  9:09 ` Boris Brezillon
2022-08-17  9:28 ` Thorsten Leemhuis
2022-08-21 14:45   ` Peter Rosin
2022-09-07  9:06 ` Tudor.Ambarus
2022-09-19 15:29   ` Miquel Raynal
2022-09-20  8:10 ` Miquel Raynal

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2099405.mp5hVA6q5l@ada \
    --to=ada@thorsis.com \
    --cc=alexandre.belloni@bootlin.com \
    --cc=bbrezillon@kernel.org \
    --cc=claudiu.beznea@microchip.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=miquel.raynal@bootlin.com \
    --cc=nicolas.ferre@microchip.com \
    --cc=peda@axentia.se \
    --cc=richard@nod.at \
    --cc=stable@vger.kernel.org \
    --cc=tudor.ambarus@microchip.com \
    --cc=vigneshr@ti.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).