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From: Dave Jiang <dave.jiang@intel.com>
To: Alison Schofield <alison.schofield@intel.com>
Cc: <linux-cxl@vger.kernel.org>, <dave@stgolabs.net>,
	<jonathan.cameron@huawei.com>, <vishal.l.verma@intel.com>,
	<ira.weiny@intel.com>, <dan.j.williams@intel.com>
Subject: Re: [PATCH] cxl: Convert pioson ops rwsem usages to scope based resource management
Date: Wed, 15 Nov 2023 16:55:11 -0700	[thread overview]
Message-ID: <c35ce419-4881-4cb9-999e-d3034ecad8ab@intel.com> (raw)
In-Reply-To: <ZVVVH8ITotdk1nyN@aschofie-mobl2>



On 11/15/23 16:32, Alison Schofield wrote:
> On Tue, Nov 14, 2023 at 11:25:20AM -0700, Dave Jiang wrote:
>> Cleanup the rwsem usages in the poison ops to reduce complexity and reduce
>> code lines.
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>
>> Hi Alison, follow on patch to yours. Can't be backported, but nice clean
>> up going forward.
> 
> Tell me more about your backport worry.  Are we expected to avoid using
> the new guard any place where there is a backport possibility?  

Given that there's none of the cleanup.h support in stable kernels, I don't see how we can backport the guard() code automatically. Thus your original fix with a fixes tag plus a new cleanup patch follow on w/o backport issues seems necessary. Otherwise a separate backport patch would be needed no?
> 
> I'm thinking I should just rev the patch with your updates.
> 
>>
>>  drivers/cxl/core/memdev.c |   32 ++++++++++++--------------------
>>  1 file changed, 12 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
>> index 961da365b097..9ab748fadb38 100644
>> --- a/drivers/cxl/core/memdev.c
>> +++ b/drivers/cxl/core/memdev.c
>> @@ -227,8 +227,8 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd)
>>  	if (!port || !is_cxl_endpoint(port))
>>  		return -EINVAL;
>>  
>> -	down_read(&cxl_region_rwsem);
>> -	down_read(&cxl_dpa_rwsem);
>> +	guard(rwsem_read)(&cxl_region_rwsem);
>> +	guard(rwsem_read)(&cxl_dpa_rwsem);
>>  
>>  	if (cxl_num_decoders_committed(port) == 0) {
>>  		/* No regions mapped to this memdev */
>> @@ -237,8 +237,6 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd)
>>  		/* Regions mapped, collect poison by endpoint */
>>  		rc =  cxl_get_poison_by_endpoint(port);
>>  	}
>> -	up_read(&cxl_dpa_rwsem);
>> -	up_read(&cxl_region_rwsem);
>>  
>>  	return rc;
>>  }
>> @@ -324,12 +322,12 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  	if (!IS_ENABLED(CONFIG_DEBUG_FS))
>>  		return 0;
>>  
>> -	down_read(&cxl_region_rwsem);
>> -	down_read(&cxl_dpa_rwsem);
>> +	guard(rwsem_read)(&cxl_region_rwsem);
>> +	guard(rwsem_read)(&cxl_dpa_rwsem);
>>  
>>  	rc = cxl_validate_poison_dpa(cxlmd, dpa);
>>  	if (rc)
>> -		goto out;
>> +		return rc;
>>  
>>  	inject.address = cpu_to_le64(dpa);
>>  	mbox_cmd = (struct cxl_mbox_cmd) {
>> @@ -339,7 +337,7 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  	};
>>  	rc = cxl_internal_send_cmd(mds, &mbox_cmd);
>>  	if (rc)
>> -		goto out;
>> +		return rc;
>>  
>>  	cxlr = cxl_dpa_to_region(cxlmd, dpa);
>>  	if (cxlr)
>> @@ -352,11 +350,8 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  		.length = cpu_to_le32(1),
>>  	};
>>  	trace_cxl_poison(cxlmd, cxlr, &record, 0, 0, CXL_POISON_TRACE_INJECT);
>> -out:
>> -	up_read(&cxl_dpa_rwsem);
>> -	up_read(&cxl_region_rwsem);
>>  
>> -	return rc;
>> +	return 0;
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_inject_poison, CXL);
>>  
>> @@ -372,12 +367,12 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  	if (!IS_ENABLED(CONFIG_DEBUG_FS))
>>  		return 0;
>>  
>> -	down_read(&cxl_region_rwsem);
>> -	down_read(&cxl_dpa_rwsem);
>> +	guard(rwsem_read)(&cxl_region_rwsem);
>> +	guard(rwsem_read)(&cxl_dpa_rwsem);
>>  
>>  	rc = cxl_validate_poison_dpa(cxlmd, dpa);
>>  	if (rc)
>> -		goto out;
>> +		return rc;
>>  
>>  	/*
>>  	 * In CXL 3.0 Spec 8.2.9.8.4.3, the Clear Poison mailbox command
>> @@ -396,7 +391,7 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  
>>  	rc = cxl_internal_send_cmd(mds, &mbox_cmd);
>>  	if (rc)
>> -		goto out;
>> +		return rc;
>>  
>>  	cxlr = cxl_dpa_to_region(cxlmd, dpa);
>>  	if (cxlr)
>> @@ -409,11 +404,8 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
>>  		.length = cpu_to_le32(1),
>>  	};
>>  	trace_cxl_poison(cxlmd, cxlr, &record, 0, 0, CXL_POISON_TRACE_CLEAR);
>> -out:
>> -	up_read(&cxl_dpa_rwsem);
>> -	up_read(&cxl_region_rwsem);
>>  
>> -	return rc;
>> +	return 0;
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_clear_poison, CXL);
>>  
>>
>>

  reply	other threads:[~2023-11-15 23:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-14  2:53 [PATCH] cxl/core: Hold the region rwsem during poison ops alison.schofield
2023-11-14 18:20 ` Dave Jiang
2023-11-14 18:25 ` [PATCH] cxl: Convert pioson ops rwsem usages to scope based resource management Dave Jiang
2023-11-15 23:32   ` Alison Schofield
2023-11-15 23:55     ` Dave Jiang [this message]
2023-11-16  2:17       ` Alison Schofield
2023-11-16 16:27         ` Dave Jiang
2023-11-23  1:12         ` Dan Williams
2023-11-23  1:33           ` Dan Williams
2023-11-16 22:14 ` [PATCH] cxl/core: Hold the region rwsem during poison ops Davidlohr Bueso
2023-11-20 19:07   ` Alison Schofield
2023-11-23  1:48 ` Dan Williams
2023-11-27  0:03   ` Alison Schofield

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