fpga: region: check for child regions before allocing image info

During a device tree overlay pre-apply notification, the check
for child FPGA regions can happen slightly earlier.  This saves
us from allocating the FPGA image info that just gets thrown
away.

This is a baby step in refactoring the FPGA region code to
separate out common FPGA region code from FPGA region
Device Tree overlay support.

Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index d78f444c1350..afac5433978b 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -355,15 +355,19 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
         const char *firmware_name;
         int ret;
 
-        info = fpga_image_info_alloc(dev);
-        if (!info)
-                return -ENOMEM;
-
-        /* Reject overlay if child FPGA Regions have firmware-name property */
+        /*
+         * Reject overlay if child FPGA Regions added in the overlay have
+         * firmware-name property (would mean that an FPGA region that has
+         * not been added to the live tree yet is doing FPGA programming).
+         */
         ret = child_regions_with_firmware(nd->overlay);
         if (ret)
                 return ret;
 
+        info = fpga_image_info_alloc(dev);
+        if (!info)
+                return -ENOMEM;
+
         /* Read FPGA region properties from the overlay */
         if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
                 info->flags |= FPGA_MGR_PARTIAL_RECONFIG;