From: John Stultz <john.stultz@linaro.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: "Sandeep Patil" <sspatil@google.com>,
"DRI mailing list" <dri-devel@lists.freedesktop.org>,
"Ezequiel Garcia" <ezequiel@collabora.com>,
"James Jones" <jajones@nvidia.com>,
lkml <linux-kernel@vger.kernel.org>,
"Liam Mark" <lmark@codeaurora.org>,
"Laura Abbott" <labbott@kernel.org>,
"Chris Goldsworthy" <cgoldswo@codeaurora.org>,
"Hridya Valsaraju" <hridya@google.com>,
"Ørjan Eide" <orjan.eide@arm.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Daniel Mentz" <danielmentz@google.com>
Subject: Re: [RESEND][PATCH 2/3] dma-buf: heaps: Add a WARN_ON should the vmap_cnt go negative
Date: Fri, 22 Jan 2021 14:35:07 -0800 [thread overview]
Message-ID: <CALAqxLW-Z3-Zcwkeuard5vfU_bAZkRRsAo2fX=3Wwp2-yURiuA@mail.gmail.com> (raw)
In-Reply-To: <CAJuCfpGRkM+h16SJp7gJOaAhy+gFw1-++WP8kavOjRj3MHcpBQ@mail.gmail.com>
On Fri, Jan 22, 2021 at 2:21 PM Suren Baghdasaryan <surenb@google.com> wrote:
> On Thu, Jan 21, 2021 at 11:56 PM Sumit Semwal <sumit.semwal@linaro.org> wrote:
> > On Wed, 20 Jan 2021 at 02:15, John Stultz <john.stultz@linaro.org> wrote:
> > >
> > > We shouldn't vunmap more then we vmap, but if we do, make
> > > sure we complain loudly.
> >
> > I was checking the general usage of vunmap in the kernel, and I
> > couldn't find many instances where we need to WARN_ON for the vunmap
> > count more than vmap count. Is there a specific need for this in the heaps?
>
> Hi Sumit,
> My worry was that buffer->vmap_cnt could silently go negative. But if
> this warning is not consistent with other places we do refcounted
> vmap/vunmap then feel free to ignore my suggestion.
>
Yea,
My sense is that it didn't seem like it would hurt, and if the
warning happened to be tripped, it would be good to catch.
However, if you are skeptical, feel free to drop that patch from this
series for now (it shouldn't impact the following patches).
thanks
-john
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2021-01-22 22:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-19 20:45 [RESEND][PATCH 1/3] dma-buf: system_heap: Make sure to return an error if we abort John Stultz
2021-01-19 20:45 ` [RESEND][PATCH 2/3] dma-buf: heaps: Add a WARN_ON should the vmap_cnt go negative John Stultz
2021-01-22 7:56 ` Sumit Semwal
2021-01-22 22:20 ` Suren Baghdasaryan
2021-01-22 22:35 ` John Stultz [this message]
2021-01-19 20:45 ` [RESEND][PATCH 3/3] dma-buf: heaps: Rework heep allocation hooks to return struct dma_buf instead of fd John Stultz
2021-01-21 13:37 ` Sumit Semwal
2021-01-21 13:28 ` [RESEND][PATCH 1/3] dma-buf: system_heap: Make sure to return an error if we abort Sumit Semwal
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='CALAqxLW-Z3-Zcwkeuard5vfU_bAZkRRsAo2fX=3Wwp2-yURiuA@mail.gmail.com' \
--to=john.stultz@linaro.org \
--cc=cgoldswo@codeaurora.org \
--cc=danielmentz@google.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=ezequiel@collabora.com \
--cc=hridya@google.com \
--cc=jajones@nvidia.com \
--cc=labbott@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=lmark@codeaurora.org \
--cc=orjan.eide@arm.com \
--cc=robin.murphy@arm.com \
--cc=sspatil@google.com \
--cc=surenb@google.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).