netdev - Re: [PATCH net] bnxt_en: do not map packet buffers twice

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

Message-ID: <20231215083759.0702559d@kernel.org>
Date: Fri, 15 Dec 2023 08:37:59 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Michael Chan <michael.chan@...adcom.com>, Andy Gospodarek
 <andrew.gospodarek@...adcom.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, edumazet@...gle.com,
 pabeni@...hat.com, bpf@...r.kernel.org, hawk@...nel.org, ast@...nel.org,
 daniel@...earbox.net, john.fastabend@...il.com, Somnath Kotur
 <somnath.kotur@...adcom.com>
Subject: Re: [PATCH net] bnxt_en: do not map packet buffers twice

On Thu, 14 Dec 2023 13:31:38 -0800 Michael Chan wrote:
> From: Andy Gospodarek <andrew.gospodarek@...adcom.com>
> 
> Remove double-mapping of DMA buffers as it can prevent page pool entries
> from being freed.  Mapping is managed by page pool infrastructure and
> was previously managed by the driver in __bnxt_alloc_rx_page before
> allowing the page pool infrastructure to manage it.

This patch is all good, but I'm confused by the handling of head.
Do you recycle it immediately and hope that the Tx happens before
the Rx gets around to using the recycled page again? Am I misreading?