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Date:   Tue, 7 Dec 2021 11:30:37 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Kees Cook <keescook@chromium.org>, Jens Axboe <axboe@kernel.dk>,
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        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] block: switch to atomic_t for request references
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On Mon, Dec 06, 2021 at 04:13:00PM -0800, Linus Torvalds wrote:

> IOW, I think that "try_get_page()" function is basically the *much*
> superior version of what is currently a broken "refcount_inc()".
> 
> And yes, it does warn about that overflow case that you claim only
> refcount_t does. And does so without the broken semantics that
> refcount h as.

That places the burden of the unlikely overflow case on the user. Now
every driver author needs to consider the overflow case and have a
corresponding error path. How many bugs will that introduce?

Why is saturation; iow. leaking the memory, a worse option than having
bad/broken/never-tested error paths all over the kernel?