From: Wei Yang <richardw.yang@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH] libnvdimm, pfn: not allocate nd_pfn->pfn_sb if already allocated
Date: Fri, 18 Jan 2019 13:03:33 +0800 [thread overview]
Message-ID: <20190118050333.GA4233@richard> (raw)
In-Reply-To: <CAPcyv4jOA-S=Z-0mCUW7d4+6gwHNEe1egaFrbyNq5UJL7Uz=Ow@mail.gmail.com>
On Thu, Jan 17, 2019 at 08:31:56PM -0800, Dan Williams wrote:
>On Thu, Jan 17, 2019 at 7:36 PM Wei Yang <richardw.yang@linux.intel.com> wrote:
>>
>> In current implementation, we might re-allocate nd_pfn->pfn_sb.
>>
>> For example:
>>
>> nd_dax_probe()
>> nd_pfn->pfn_sb = devm_kzalloc()
>>
>> dax_pmem_probe()
>> nvdimm_setup_pfn()
>> nd_pfn_init()
>> nd_pfn->pfn_sb = devm_kzalloc()
>>
>> This patch checks nd_pfn->pfn_sb before allocating it in nd_pfn_init().
>
>Ugh, this patch is unfortunately uncovering a deeper problem.
>nvdimm_setup_pfn() should not be calling nd_pfn_init(). This
>effectively is always re-initializing the info-block, benign but
>unnecessary. Instead it needs to be using nd_pfn_validate() followed
>by an __nvdimm_setup_pfn() in the dax_pmem_probe() path.
>
>Good find!
So we should fix this like:
dax_pmem_probe()
nd_pfn_validate()
__nvdimm_setup_pfn()
Is my understanding correct?
--
Wei Yang
Help you, Help me
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next prev parent reply other threads:[~2019-01-18 5:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-18 3:35 [PATCH] libnvdimm, pfn: not allocate nd_pfn->pfn_sb if already allocated Wei Yang
2019-01-18 4:31 ` Dan Williams
2019-01-18 5:03 ` Wei Yang [this message]
2019-01-18 5:05 ` Dan Williams
2019-01-18 7:31 ` Wei Yang
2019-01-18 8:38 ` Dan Williams
2019-01-18 18:59 ` Dan Williams
2019-01-21 0:50 ` Wei Yang
2019-01-21 3:28 ` Dan Williams
2019-01-21 0:24 ` Wei Yang
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