Message-ID: <36c2bc37-714b-2251-942f-1d02f4b77d5a@linux.alibaba.com>
Date:   Mon, 13 Feb 2023 17:35:47 +0800
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Subject: Re: [PATCH] swiotlb: fix the deadlock in swiotlb_do_find_slots
To:     kernel test robot <lkp@intel.com>, hch@lst.de,
        m.szyprowski@samsung.com
Cc:     llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
        robin.murphy@arm.com, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, xiaokang.hxk@alibaba-inc.com
References: <20230213063604.127526-1-GuoRui.Yu@linux.alibaba.com>
 <202302131748.pa5NGbb9-lkp@intel.com>
From:   Guorui Yu <GuoRui.Yu@linux.alibaba.com>
In-Reply-To: <202302131748.pa5NGbb9-lkp@intel.com>
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在 2023/2/13 17:28, kernel test robot 写道:
> Hi GuoRui.Yu",
> 
> Thank you for the patch! Perhaps something to improve:
> 
>     654		spin_lock_irqsave(&area->lock, flags);
>     655		if (unlikely(nslots > mem->area_nslabs - area->used))
>     656			goto not_found;
>     657	
>     658		slot_base = area_index * mem->area_nslabs;
>     659		index = wrap = wrap_area_index(mem, ALIGN(area->index, stride));
index_nowrap should be initialized to "index" here, and I will add this 
in v2.

I have done some stress tests locally to check if they can avoid the 
deadlock but they did not reveal this problem, I will pay more attention 
next time.
>     660	
>     661		do {

Guorui