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Date: Wed, 23 Sep 2026 11:28:52 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Murali Krishna <muralikrishna2444b@gmail.com>
Cc: srini@kernel.org, ekansh.gupta@oss.qualcomm.com,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: misc: fastrpc: is a ctx_idr IDR -> XArray conversion wanted?
Message-ID: <2026092338-banking-tactics-2cfb@gregkh>
References: <20260923082254.15312-1-muralikrishna2444b@gmail.com>
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In-Reply-To: <20260923082254.15312-1-muralikrishna2444b@gmail.com>

On Wed, Sep 23, 2026 at 01:52:05PM +0530, Murali Krishna wrote:
> Hi Srini, Ekansh,
> 
> I am new to kernel development and would like to start contributing. I
> do not have much experience yet, but I am willing to learn and to put in
> the work properly.
> 
> Documentation/core-api/idr.rst states that the IDR interface is
> deprecated in favour of the XArray, and fastrpc's ctx_idr is still an
> IDR. I have a conversion prepared -- XA_FLAGS_ALLOC1, xa_alloc_cyclic()
> with the cursor kept in struct fastrpc_channel_ctx, xa_load() and
> xa_erase(), and cctx->lock left as it is -- with no intended functional
> change.
> 
> Before posting it, I would rather ask than take up your review time: is
> such a conversion wanted in fastrpc, or is the IDR usage here fine as it
> is? I have seen similar conversions in other subsystems declined as
> unnecessary, so I did not want to assume.

I doubt it's really needed unless you can prove some sort of advantage
for the change?  Is it faster on a measurable path, or less memory or
something else that would justify the churn?

idr is still a fine structure/api for many things, they don't all have
to go away, otherwise we would have done so long ago.

thanks,

greg k-h