ARM: omap2: simplify allocation for omap_device

Use a flexible array member (FAM) to combine hwmods array allocation
with the omap_device structure. This reduces the number of allocations
from two separate calls (one for the device, one for the array) to a
single allocation, improving efficiency and reducing memory fragmentation.

The FAM approach also enables bounds checking through __counted_by(),
which provides runtime verification that array accesses stay within
the allocated size. This improves security and helps catch bugs during
development.

Simplify error handling by removing the unnecessary multi-label goto
pattern. The new code is more straightforward: allocate, verify, copy
data, and either return success or error immediately.

Also removes the now-redundant kfree(od->hwmods) in omap_device_delete()
since the hwmods array is now embedded in the structure rather than
separately allocated.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20260330213528.18187-1-rosenp@gmail.com
Signed-off-by: Kevin Hilman (TI) <khilman@baylibre.com>

diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
index 79db4c49ffc9cec748eee57cd1b90791f6eaea56..77a75b0b9ae69c85c4dbb2968a1ad2dedd3ad814 100644 (file)
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -307,35 +307,27 @@ static struct omap_device *omap_device_alloc(struct platform_device *pdev,
        int ret = -ENOMEM;
        struct omap_device *od;
        int i;
-       struct omap_hwmod **hwmods;
+       struct omap_hwmod *hwmod;
 
-       od = kzalloc_obj(struct omap_device);
-       if (!od)
-               goto oda_exit1;
+       od = kzalloc_flex(*od, hwmods, oh_cnt);
+       if (!od) {
+               dev_err(&pdev->dev, "omap_device: build failed (%d)\n", ret);
+               return ERR_PTR(ret);
+       }
 
        od->hwmods_cnt = oh_cnt;
+       memcpy(od->hwmods, ohs, oh_cnt * sizeof(*od->hwmods));
 
-       hwmods = kmemdup_array(ohs, oh_cnt, sizeof(*hwmods), GFP_KERNEL);
-       if (!hwmods)
-               goto oda_exit2;
-
-       od->hwmods = hwmods;
        od->pdev = pdev;
        pdev->archdata.od = od;
 
        for (i = 0; i < oh_cnt; i++) {
-               hwmods[i]->od = od;
-               _add_hwmod_clocks_clkdev(od, hwmods[i]);
+               hwmod = od->hwmods[i];
+               hwmod->od = od;
+               _add_hwmod_clocks_clkdev(od, hwmod);
        }
 
        return od;
-
-oda_exit2:
-       kfree(od);
-oda_exit1:
-       dev_err(&pdev->dev, "omap_device: build failed (%d)\n", ret);
-
-       return ERR_PTR(ret);
 }
 
 static void omap_device_delete(struct omap_device *od)
@@ -344,7 +336,6 @@ static void omap_device_delete(struct omap_device *od)
                return;
 
        od->pdev->archdata.od = NULL;
-       kfree(od->hwmods);
        kfree(od);
 }
 

diff --git a/arch/arm/mach-omap2/omap_device.h b/arch/arm/mach-omap2/omap_device.h
index aa8096ecb23caad223f5480718673ebda8d3ee45..fae09cfce137a470b042a5cd600f2707f137beda 100644 (file)
--- a/arch/arm/mach-omap2/omap_device.h
+++ b/arch/arm/mach-omap2/omap_device.h
@@ -37,11 +37,11 @@
 /**
  * struct omap_device - omap_device wrapper for platform_devices
  * @pdev: platform_device
- * @hwmods: (one .. many per omap_device)
  * @hwmods_cnt: ARRAY_SIZE() of @hwmods
  * @_state: one of OMAP_DEVICE_STATE_* (see above)
  * @flags: device flags
  * @_driver_status: one of BUS_NOTIFY_*_DRIVER from <linux/device.h>
+ * @hwmods: (one .. many per omap_device)
  *
  * Integrates omap_hwmod data into Linux platform_device.
  *
@@ -51,11 +51,11 @@
  */
 struct omap_device {
        struct platform_device          *pdev;
-       struct omap_hwmod               **hwmods;
        unsigned long                   _driver_status;
        u8                              hwmods_cnt;
        u8                              _state;
        u8                              flags;
+       struct omap_hwmod               *hwmods[] __counted_by(hwmods_cnt);
 };
 
 /* Device driver interface (call via platform_data fn ptrs) */