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Date: Thu, 6 Apr 2017 09:16:34 -0500
From: Alan Tull <atull@...nel.org>
To: Moritz Fischer <mdf@...nel.org>
Cc: linux-kernel <linux-kernel@...r.kernel.org>,
linux-fpga@...r.kernel.org
Subject: Re: [PATCH 4/5] fpga-mgr: separate getting/locking FPGA manager
On Wed, Apr 5, 2017 at 11:07 PM, Moritz Fischer <mdf@...nel.org> wrote:
> Hi Alan,
>
> minor nits, inline
>
> On Mon, Mar 13, 2017 at 04:53:32PM -0500, Alan Tull wrote:
>> Add fpga_mgr_lock/unlock functions that get a mutex for
>> exclusive use.
>>
>> of_fpga_mgr_get, fpga_mgr_get, and fpga_mgr_put no longer lock
>> the FPGA manager mutex.
>>
>> This makes it more straightforward to save a reference to
>> a FPGA manager and only attempting to lock it when programming
>> the FPGA.
>>
>> Signed-off-by: Alan Tull <atull@...nel.org>
>> ---
>> drivers/fpga/fpga-mgr.c | 44 +++++++++++++++++++++++++++++++------------
>> drivers/fpga/fpga-region.c | 13 +++++++++++--
>> include/linux/fpga/fpga-mgr.h | 3 +++
>> 3 files changed, 46 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
>> index fde605b..f7c3648 100644
>> --- a/drivers/fpga/fpga-mgr.c
>> +++ b/drivers/fpga/fpga-mgr.c
>> @@ -376,28 +376,19 @@ ATTRIBUTE_GROUPS(fpga_mgr);
>> struct fpga_manager *__fpga_mgr_get(struct device *dev)
>> {
>> struct fpga_manager *mgr;
>> - int ret = -ENODEV;
>>
>> mgr = to_fpga_manager(dev);
>> if (!mgr)
>> goto err_dev;
>>
>> - /* Get exclusive use of fpga manager */
>> - if (!mutex_trylock(&mgr->ref_mutex)) {
>> - ret = -EBUSY;
>> - goto err_dev;
>> - }
>> -
>> if (!try_module_get(dev->parent->driver->owner))
>> - goto err_ll_mod;
>> + goto err_dev;
>>
>> return mgr;
>>
>> -err_ll_mod:
>> - mutex_unlock(&mgr->ref_mutex);
>> err_dev:
>> put_device(dev);
>> - return ERR_PTR(ret);
>> + return ERR_PTR(-ENODEV);
>> }
>>
>> static int fpga_mgr_dev_match(struct device *dev, const void *data)
>> @@ -457,12 +448,41 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get);
>> void fpga_mgr_put(struct fpga_manager *mgr)
>> {
>> module_put(mgr->dev.parent->driver->owner);
>> - mutex_unlock(&mgr->ref_mutex);
>> put_device(&mgr->dev);
>> }
>> EXPORT_SYMBOL_GPL(fpga_mgr_put);
>>
>> /**
>> + * fpga_mgr_lock - Lock FPGA manager for exclusive use
>> + * @mgr: fpga manager
>> + *
>> + * Given a pointer to FPGA Manager (from fpga_mgr_get() or
>> + * of_fpga_mgr_put()) attempt to get the mutex.
>> + *
>> + * Return: 0 for success or -EBUSY
>> + */
>> +int fpga_mgr_lock(struct fpga_manager *mgr)
>> +{
>> + if (!mutex_trylock(&mgr->ref_mutex)) {
>> + dev_err(&mgr->dev, "FPGA manager is in use.\n");
>> + return -EBUSY;
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(fpga_mgr_lock);
>> +
>> +/**
>> + * fpga_mgr_unlock - Unlock FPGA manager
>> + * @mgr: fpga manager
>> + */
>> +void fpga_mgr_unlock(struct fpga_manager *mgr)
>> +{
>> + mutex_unlock(&mgr->ref_mutex);
>> +}
>> +EXPORT_SYMBOL_GPL(fpga_mgr_unlock);
>> +
>> +/**
>> * fpga_mgr_register - register a low level fpga manager driver
>> * @dev: fpga manager device from pdev
>> * @name: fpga manager name
>> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
>> index 294556e..815f178 100644
>> --- a/drivers/fpga/fpga-region.c
>> +++ b/drivers/fpga/fpga-region.c
>> @@ -125,7 +125,7 @@ static void fpga_region_put(struct fpga_region *region)
>> }
>>
>> /**
>> - * fpga_region_get_manager - get exclusive reference for FPGA manager
>> + * fpga_region_get_manager - get reference for FPGA manager
>> * @region: FPGA region
>> *
>> * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
>> @@ -245,10 +245,16 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>> return PTR_ERR(mgr);
>> }
>>
>> + ret = fpga_mgr_lock(mgr);
>> + if (ret) {
>> + pr_err("FPGA manager is busy\n");
>
> Am I missing something here, or could you use dev_err(&mgr->dev, ...)
> here?
Hi Moritz,
I agree, I can go though and look for pr_* print messages and
change them to dev_* in functions where I have the device.
Thanks!
Alan
>
>> + goto err_put_mgr;
>> + }
>> +
>> ret = fpga_region_get_bridges(region, overlay);
>> if (ret) {
>> pr_err("failed to get fpga region bridges\n");
>
> Same here, (I know this is not part of this patch), maybe the above is
> for consistency reasons then. Maybe I'm missing something.
>> - goto err_put_mgr;
>> + goto err_unlock_mgr;
>> }
>>
>> ret = fpga_bridges_disable(®ion->bridge_list);
>> @@ -269,6 +275,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>> goto err_put_br;
>> }
>>
>> + fpga_mgr_unlock(mgr);
>> fpga_mgr_put(mgr);
>> fpga_region_put(region);
>>
>> @@ -276,6 +283,8 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>>
>> err_put_br:
>> fpga_bridges_put(®ion->bridge_list);
>> +err_unlock_mgr:
>> + fpga_mgr_unlock(mgr);
>> err_put_mgr:
>> fpga_mgr_put(mgr);
>> fpga_region_put(region);
>> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
>> index 45df05a..ae970ca 100644
>> --- a/include/linux/fpga/fpga-mgr.h
>> +++ b/include/linux/fpga/fpga-mgr.h
>> @@ -149,6 +149,9 @@ int fpga_mgr_firmware_load(struct fpga_manager *mgr,
>>
>> int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info);
>>
>> +int fpga_mgr_lock(struct fpga_manager *mgr);
>> +void fpga_mgr_unlock(struct fpga_manager *mgr);
>> +
>> struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
>>
>> struct fpga_manager *fpga_mgr_get(struct device *dev);
>> --
>> 2.7.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-fpga" in
>> the body of a message to majordomo@...r.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> Cheers,
>
> Moritz
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