Re: [PATCH] fpga: fpga-region: comment on fpga_region_program_fpga locking

[matthew . gerlach]

On Thu, 25 Jan 2018, Alan Tull wrote:

Hi Alan,

I seem to remember issue coming up a couple of times.
I think this comment will be very helpful.

Matthew Gerlach

> Add a comment to the header of fpga_region_program_fpga()
> regarding locking of the bridges.
>
> Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
> ---
> drivers/fpga/fpga-region.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index edab2a2..cb0603e 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -95,6 +95,11 @@ static void fpga_region_put(struct fpga_region *region)
>  * fpga_region_program_fpga - program FPGA
>  * @region: FPGA region
>  * Program an FPGA using fpga image info (region->info).
> + * If the region has a get_bridges function, the exclusive reference for the
> + * bridges will be held if programming succeeds.  This is intended to prevent
> + * reprogramming the region until the caller considers it safe to do so.
> + * The caller will need to call fpga_bridges_put() before attempting to
> + * reprogram the region.
>  * Return 0 for success or negative error code.
>  */
> int fpga_region_program_fpga(struct fpga_region *region)
> --
> 2.7.4
>
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