linux-kernel - DMAENGINE: Client reuse of desc

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>] [day] [month] [year] [list]

Message-ID: <AANLkTikDEF=K05Pfi62+EcDRACU7horv7w54bRn_HwtQ@mail.gmail.com>
Date:	Mon, 25 Oct 2010 18:43:12 +0200
From:	Per Forlin <per.lkml@...il.com>
To:	dan.j.williams@...el.com
Cc:	linux-kernel@...r.kernel.org
Subject: DMAENGINE: Client reuse of desc

Hi,

DMA_CTRL_ACK is used if the client needs to set up a dependency chain
of descriptor. This mean the driver cannot reuse or free the
descriptor until the client release it. I wonder if the client is
permitted/safe to reuse the descriptor and submit it again to the
driver? Or would dmaengine need an additional flag for this feature.

I know that the intent of DMA_CTRL_ACK is not to allow reuse of desc
from a client perspective. I am asking because I made this assumption
when implementing it in ste_dma40.

Example:
The client prepares a desc "A", submits "A" and starts the transfer.
When tx finished, the client then fills in new data in the desc
"A"-buffer and submits it again.

/Per
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/