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From: Russ Weight <russell.h.weight@intel.com>
To: Xu Yilun <yilun.xu@intel.com>
Cc: <mdf@kernel.org>, <linux-fpga@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <trix@redhat.com>,
	<lgoncalv@redhat.com>, <hao.wu@intel.com>,
	<matthew.gerlach@intel.com>
Subject: Re: [PATCH v16 5/5] fpga: image-load: enable cancel of image upload
Date: Fri, 24 Sep 2021 17:29:28 -0700	[thread overview]
Message-ID: <d03bc8f3-5afc-207c-62db-68bb4d533e36@intel.com> (raw)
In-Reply-To: <20210924145338.GA1342075@yilunxu-OptiPlex-7050>



On 9/24/21 7:53 AM, Xu Yilun wrote:
> On Wed, Sep 22, 2021 at 05:10:56PM -0700, Russ Weight wrote:
>> Extend the FPGA Image Load framework to include a cancel IOCTL that can be
>> used to request that an image upload be canceled. The IOCTL may return
>> EBUSY if it cannot be canceled by software or ENODEV if there is no update
>> in progress.
>>
>> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
>> ---
>> v16:
>>  - This was previously patch 6/6
>>  - Amend fpga_image_load_release() to request cancellation of an ongoing
>>    update when possible.
>> v15:
>>  - Compare to previous patch:
>>      [PATCH v14 6/6] fpga: sec-mgr: enable cancel of secure update
>>  - Changed file, symbol, and config names to reflect the new driver name
>>  - Cancel is now initiated by IOCT instead of sysfs
>>  - Removed signed-off/reviewed-by tags
>> v14:
>>  - Updated ABI documentation date and kernel version
>> v13:
>>   - No change
>> v12:
>>   - Updated Date and KernelVersion fields in ABI documentation
>> v11:
>>   - No change
>> v10:
>>   - Rebased to 5.12-rc2 next
>>   - Updated Date and KernelVersion in ABI documentation
>> v9:
>>   - Updated Date and KernelVersion in ABI documentation
>> v8:
>>   - No change
>> v7:
>>   - Changed Date in documentation file to December 2020
>> v6:
>>   - No change
>> v5:
>>   - No change
>> v4:
>>   - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
>>     and removed unnecessary references to "Intel".
>>   - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
>> v3:
>>   - No change
>> v2:
>>   - Bumped documentation date and version
>>   - Minor code cleanup per review comments
>> ---
>>  Documentation/fpga/fpga-image-load.rst |  6 ++++
>>  drivers/fpga/fpga-image-load.c         | 49 +++++++++++++++++++++++---
>>  include/linux/fpga/fpga-image-load.h   |  1 +
>>  include/uapi/linux/fpga-image-load.h   |  2 ++
>>  4 files changed, 53 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/fpga/fpga-image-load.rst b/Documentation/fpga/fpga-image-load.rst
>> index 572e18afebb9..21fa85f18680 100644
>> --- a/Documentation/fpga/fpga-image-load.rst
>> +++ b/Documentation/fpga/fpga-image-load.rst
>> @@ -40,3 +40,9 @@ FPGA_IMAGE_LOAD_STATUS:
>>  Collect status for an on-going image upload. The status returned includes
>>  how much data remains to be transferred, the progress of the image load,
>>  and error information in the case of a failure.
>> +
>> +FPGA_IMAGE_LOAD_CANCEL:
>> +
>> +Request that a on-going image upload be cancelled. This IOCTL may return
> 		an
I'll fix it
>> +EBUSY if it cannot be cancelled by software or ENODEV if there is no update
>    -EBUSY					 -ENODEV

From the userspace perspective, these are seen as positive errno numbers.
I think this is OK as is? If not, I need to change it in other places as well.
>
>> +in progress.
>> diff --git a/drivers/fpga/fpga-image-load.c b/drivers/fpga/fpga-image-load.c
>> index 2e9a5a041535..a95d18077d58 100644
>> --- a/drivers/fpga/fpga-image-load.c
>> +++ b/drivers/fpga/fpga-image-load.c
>> @@ -46,6 +46,24 @@ static void fpga_image_dev_error(struct fpga_image_load *imgld, u32 err_code)
>>  	imgld->ops->cancel(imgld);
>>  }
>>  
>> +static int fpga_image_prog_transition(struct fpga_image_load *imgld,
>> +				      u32 new_progress)
>> +{
>> +	int ret = 0;
>> +
>> +	mutex_lock(&imgld->lock);
>> +	if (imgld->request_cancel) {
>> +		imgld->err_progress = imgld->progress;
>> +		imgld->err_code = FPGA_IMAGE_ERR_CANCELED;
>> +		imgld->ops->cancel(imgld);
> We could only cancel in 2 conditions.
> This is the first one: on progress transition.
>
>> +		ret = -ECANCELED;
>> +	} else {
>> +		imgld->progress = new_progress;
>> +	}
>> +	mutex_unlock(&imgld->lock);
>> +	return ret;
>> +}
>> +
>>  static void fpga_image_prog_complete(struct fpga_image_load *imgld)
>>  {
>>  	mutex_lock(&imgld->lock);
>> @@ -79,8 +97,10 @@ static void fpga_image_do_load(struct work_struct *work)
>>  		goto modput_exit;
>>  	}
>>  
>> -	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_WRITING);
>> -	while (imgld->remaining_size) {
>> +	if (fpga_image_prog_transition(imgld, FPGA_IMAGE_PROG_WRITING))
>> +		goto done;
>> +
>> +	while (imgld->remaining_size && !imgld->request_cancel) {
> This is the second condition: when we finished a block write. But if the
> low level driver accepts the whole block size, we cannot cancel in
> between.
>
> Actually the framework doesn't know when to successfully cancel an
> update. It depends on the hardware.
>
> So maybe the framework just calls cancel() immediately in IOCTL,
> let the low level driver decides if it is feasible and how to cancel.

Yes - I agree. This current implementation assumes too much about
the low-level driver. I have some ideas to try in the next patchset.

Thanks,
- Russ
>
> Thanks,
> Yilun
>
>>  		/*
>>  		 * The write_blk() op has the option to use the blk_size
>>  		 * value provided here, or to modify it to something more
>> @@ -105,7 +125,9 @@ static void fpga_image_do_load(struct work_struct *work)
>>  		cond_resched();
>>  	}
>>  
>> -	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_PROGRAMMING);
>> +	if (fpga_image_prog_transition(imgld, FPGA_IMAGE_PROG_PROGRAMMING))
>> +		goto done;
>> +
>>  	ret = imgld->ops->poll_complete(imgld);
>>  	if (ret != FPGA_IMAGE_ERR_NONE)
>>  		fpga_image_dev_error(imgld, ret);
>> @@ -178,8 +200,8 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
>>  	imgld->remaining_size = wb.size;
>>  	imgld->err_code = FPGA_IMAGE_ERR_NONE;
>>  	imgld->progress = FPGA_IMAGE_PROG_STARTING;
>> +	imgld->request_cancel = false;
>>  	queue_work(system_unbound_wq, &imgld->work);
>> -
>>  	return 0;
>>  
>>  exit_free:
>> @@ -208,7 +230,7 @@ static long fpga_image_load_ioctl(struct file *filp, unsigned int cmd,
>>  				  unsigned long arg)
>>  {
>>  	struct fpga_image_load *imgld = filp->private_data;
>> -	int ret = -ENOTTY;
>> +	int ret = 0;
>>  
>>  	mutex_lock(&imgld->lock);
>>  
>> @@ -219,6 +241,17 @@ static long fpga_image_load_ioctl(struct file *filp, unsigned int cmd,
>>  	case FPGA_IMAGE_LOAD_STATUS:
>>  		ret = fpga_image_load_ioctl_status(imgld, arg);
>>  		break;
>> +	case FPGA_IMAGE_LOAD_CANCEL:
>> +		if (imgld->progress == FPGA_IMAGE_PROG_PROGRAMMING)
>> +			ret = -EBUSY;
>> +		else if (imgld->progress == FPGA_IMAGE_PROG_IDLE)
>> +			ret = -ENODEV;
>> +		else
>> +			imgld->request_cancel = true;
>> +		break;
>> +	default:
>> +		ret = -ENOTTY;
>> +		break;
>>  	}
>>  
>>  	mutex_unlock(&imgld->lock);
>> @@ -249,6 +282,9 @@ static int fpga_image_load_release(struct inode *inode, struct file *filp)
>>  		goto close_exit;
>>  	}
>>  
>> +	if (imgld->progress != FPGA_IMAGE_PROG_PROGRAMMING)
>> +		imgld->request_cancel = true;
>> +
>>  	mutex_unlock(&imgld->lock);
>>  	flush_work(&imgld->work);
>>  
>> @@ -363,6 +399,9 @@ void fpga_image_load_unregister(struct fpga_image_load *imgld)
>>  		goto unregister;
>>  	}
>>  
>> +	if (imgld->progress != FPGA_IMAGE_PROG_PROGRAMMING)
>> +		imgld->request_cancel = true;
>> +
>>  	mutex_unlock(&imgld->lock);
>>  	flush_work(&imgld->work);
>>  
>> diff --git a/include/linux/fpga/fpga-image-load.h b/include/linux/fpga/fpga-image-load.h
>> index 8b58365893fc..8ba39d3299d9 100644
>> --- a/include/linux/fpga/fpga-image-load.h
>> +++ b/include/linux/fpga/fpga-image-load.h
>> @@ -53,6 +53,7 @@ struct fpga_image_load {
>>  	u32 progress;
>>  	u32 err_progress;		/* progress at time of error */
>>  	u32 err_code;			/* image load error code */
>> +	bool request_cancel;
>>  	bool driver_unload;
>>  	struct eventfd_ctx *finished;
>>  	void *priv;
>> diff --git a/include/uapi/linux/fpga-image-load.h b/include/uapi/linux/fpga-image-load.h
>> index dc0c9f1d78b1..da8a7452c29a 100644
>> --- a/include/uapi/linux/fpga-image-load.h
>> +++ b/include/uapi/linux/fpga-image-load.h
>> @@ -70,4 +70,6 @@ struct fpga_image_status {
>>  
>>  #define FPGA_IMAGE_LOAD_STATUS	_IOR(FPGA_IMAGE_LOAD_MAGIC, 1, struct fpga_image_status)
>>  
>> +#define FPGA_IMAGE_LOAD_CANCEL	_IO(FPGA_IMAGE_LOAD_MAGIC, 2)
>> +
>>  #endif /* _UAPI_LINUX_FPGA_IMAGE_LOAD_H */
>> -- 
>> 2.25.1


  reply	other threads:[~2021-09-25  0:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-23  0:10 [PATCH v16 0/5] FPGA Image Load (previously Security Manager) Russ Weight
2021-09-23  0:10 ` [PATCH v16 1/5] fpga: image-load: fpga image load framework Russ Weight
2021-09-23  0:10 ` [PATCH v16 2/5] fpga: image-load: enable image uploads Russ Weight
2021-09-23  8:54   ` Xu Yilun
2021-09-24  0:21     ` Russ Weight
2021-09-24  8:12   ` Xu Yilun
2021-09-24 21:32     ` Russ Weight
2021-09-26  1:10       ` Xu Yilun
2021-09-27 16:33         ` Russ Weight
2021-09-23  0:10 ` [PATCH v16 3/5] fpga: image-load: signal eventfd when complete Russ Weight
2021-09-24  8:49   ` Xu Yilun
2021-09-24 21:45     ` Russ Weight
2021-09-26  1:06       ` Xu Yilun
2021-09-23  0:10 ` [PATCH v16 4/5] fpga: image-load: add status ioctl Russ Weight
2021-09-23  0:10 ` [PATCH v16 5/5] fpga: image-load: enable cancel of image upload Russ Weight
2021-09-24 14:53   ` Xu Yilun
2021-09-25  0:29     ` Russ Weight [this message]
2021-09-26  1:16       ` Xu Yilun

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