Re: [PATCH] media: siano: add loadfirmware_handler NULL check

[Ricardo Ribalda <ribalda@xxxxxxxxxxxx>]

Hi Hans

On Sat, 3 Aug 2024 at 11:35, Hans Verkuil <hverkuil-cisco@xxxxxxxxx> wrote:
>
> Add check for a NULL value of the loadfirmware_handler to fix the
> following smatch error:
>
> drivers/media/common/siano/smscoreapi.c:1172 smscore_load_firmware_from_file() error: we previously assumed 'loadfirmware_handler' could be null (see line 1150)
>
> Note that it is a false positive, but frankly, this change makes the
> code more robust.
>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> ---
>  drivers/media/common/siano/smscoreapi.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/common/siano/smscoreapi.c b/drivers/media/common/siano/smscoreapi.c
> index b6f1eb5dbbdf..329aee411562 100644
> --- a/drivers/media/common/siano/smscoreapi.c
> +++ b/drivers/media/common/siano/smscoreapi.c
> @@ -1166,10 +1166,15 @@ static int smscore_load_firmware_from_file(struct smscore_device_t *coredev,

I cannot find any place where loadfirmware_handler is != than NULL.
Maybe it is better to clean the dead code instead?

diff --git a/drivers/media/common/siano/smscoreapi.c
b/drivers/media/common/siano/smscoreapi.c
index b6f1eb5dbbdf..3732367e0c62 100644
--- a/drivers/media/common/siano/smscoreapi.c
+++ b/drivers/media/common/siano/smscoreapi.c
@@ -1132,8 +1132,7 @@ static char *smscore_get_fw_filename(struct
smscore_device_t *coredev,
  * return: 0 on success, <0 on error.
  */
 static int smscore_load_firmware_from_file(struct smscore_device_t *coredev,
-                                          int mode,
-                                          loadfirmware_t loadfirmware_handler)
+                                          int mode)
 {
        int rc = -ENOENT;
        u8 *fw_buf;
@@ -1147,8 +1146,7 @@ static int
smscore_load_firmware_from_file(struct smscore_device_t *coredev,
        }
        pr_debug("Firmware name: %s\n", fw_filename);

-       if (!loadfirmware_handler &&
-           !(coredev->device_flags & SMS_DEVICE_FAMILY2))
+       if (!(coredev->device_flags & SMS_DEVICE_FAMILY2))
                return -EINVAL;

        rc = request_firmware(&fw, fw_filename, coredev->device);
@@ -1166,10 +1164,8 @@ static int
smscore_load_firmware_from_file(struct smscore_device_t *coredev,
                memcpy(fw_buf, fw->data, fw->size);
                fw_buf_size = fw->size;

-               rc = (coredev->device_flags & SMS_DEVICE_FAMILY2) ?
-                       smscore_load_firmware_family2(coredev, fw_buf,
fw_buf_size)
-                       : loadfirmware_handler(coredev->context, fw_buf,
-                       fw_buf_size);
+               rc = smscore_load_firmware_family2(coredev, fw_buf,
+                                                  fw_buf_size);
        }

        kfree(fw_buf);
@@ -1353,8 +1349,7 @@ int smscore_set_device_mode(struct
smscore_device_t *coredev, int mode)
                }

                if (!(coredev->modes_supported & (1 << mode))) {
-                       rc = smscore_load_firmware_from_file(coredev,
-                                                            mode, NULL);
+                       rc = smscore_load_firmware_from_file(coredev, mode);
                        if (rc >= 0)
                                pr_debug("firmware download success\n");
                } else {
diff --git a/drivers/media/common/siano/smscoreapi.h
b/drivers/media/common/siano/smscoreapi.h
index 82d9f8a64d99..3c15082ce0e3 100644
--- a/drivers/media/common/siano/smscoreapi.h
+++ b/drivers/media/common/siano/smscoreapi.h
@@ -97,7 +97,6 @@ typedef int (*hotplug_t)(struct smscore_device_t *coredev,
 typedef int (*setmode_t)(void *context, int mode);
 typedef void (*detectmode_t)(void *context, int *mode);
 typedef int (*sendrequest_t)(void *context, void *buffer, size_t size);
-typedef int (*loadfirmware_t)(void *context, void *buffer, size_t size);
 typedef int (*preload_t)(void *context);
 typedef int (*postload_t)(void *context);

@@ -1102,9 +1101,6 @@ extern int smscore_register_device(struct
smsdevice_params_t *params,
 extern void smscore_unregister_device(struct smscore_device_t *coredev);

 extern int smscore_start_device(struct smscore_device_t *coredev);
-extern int smscore_load_firmware(struct smscore_device_t *coredev,
-                                char *filename,
-                                loadfirmware_t loadfirmware_handler);

 extern int smscore_set_device_mode(struct smscore_device_t *coredev, int mode);
 extern int smscore_get_device_mode(struct smscore_device_t *coredev);

>                 memcpy(fw_buf, fw->data, fw->size);
>                 fw_buf_size = fw->size;
>
> +               /*
> +                * Note that loadfirmware_handler can't be NULL due to the
> +                * check above, but it is confusing smatch.
> +                */
>                 rc = (coredev->device_flags & SMS_DEVICE_FAMILY2) ?
> -                       smscore_load_firmware_family2(coredev, fw_buf, fw_buf_size)
> -                       : loadfirmware_handler(coredev->context, fw_buf,
> -                       fw_buf_size);
> +                     smscore_load_firmware_family2(coredev, fw_buf, fw_buf_size) :
> +                     (loadfirmware_handler ?
> +                      loadfirmware_handler(coredev->context, fw_buf, fw_buf_size) :
> +                      -EINVAL);
>         }
>
>         kfree(fw_buf);
> --
> 2.43.0
>


-- 
Ricardo Ribalda