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Date: Mon, 20 Sep 2010 18:25:37 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Alex Dubov <oakad@yahoo.com>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] MEMSTICK: add support for legacy memorysticks
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On Mon, 20 Sep 2010 18:16:03 -0700 (PDT) Alex Dubov <oakad@yahoo.com> wrote:

> However, do you have a quick
> advice for a case, were idr_pre_get happens outside spin-locked section,
> as opposed to mutex one?

It sucks, but...

again:
	if (idr_pre_get(..., GFP_KERNEL) == NULL)
		return -ENOMEM;		/* We're really out-of-memory */
	spin_lock(lock);
	if (idr_get_new(...) == -EAGAIN) {
		spin_unlock(lock);
		goto again;		/* Someone stole our preallocation! */
	}