HID: core: save one kmemdup during .probe()

Turns out the first kmemdup is only required for the .report_fixup()
driver callback. There is no need to do two kmemdup() in a row in case
.report_fixup() is not present.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://patch.msgid.link/20241001-hid-bpf-hid-generic-v3-2-2ef1019468df@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index d6bf933623e84f6b5d2e677cf325f9a3c1d7446d..6053e7cdc0c19a9db2d8bec111737e17f91c9090 100644 (file)
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1214,7 +1214,7 @@ int hid_open_report(struct hid_device *device)
        struct hid_item item;
        unsigned int size;
        const __u8 *start;
-       __u8 *buf;
+       __u8 *buf = NULL;
        const __u8 *end;
        const __u8 *next;
        int ret;
@@ -1235,14 +1235,18 @@ int hid_open_report(struct hid_device *device)
                return -ENODEV;
        size = device->bpf_rsize;
 
-       buf = kmemdup(start, size, GFP_KERNEL);
-       if (buf == NULL)
-               return -ENOMEM;
+       if (device->driver->report_fixup) {
+               /*
+                * device->driver->report_fixup() needs to work
+                * on a copy of our report descriptor so it can
+                * change it.
+                */
+               buf = kmemdup(start, size, GFP_KERNEL);
+               if (buf == NULL)
+                       return -ENOMEM;
 
-       if (device->driver->report_fixup)
                start = device->driver->report_fixup(device, buf, &size);
-       else
-               start = buf;
+       }
 
        start = kmemdup(start, size, GFP_KERNEL);
        kfree(buf);