[staging:staging-testing 278/280] drivers/most/core.c:1287 most_register_interface() error: we previously assumed 'iface' could be null (see line 1285)

[Dan Carpenter]

Hi Christian,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git staging-testing
head:   4a1a3e9bf5654e98bb48f5b074af17af96ded30d
commit: b276527539188f1f61c082ebef27803db93e536d [278/280] staging: most: move core files out of the staging area

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp at intel.com>
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>

smatch warnings:
drivers/most/core.c:1287 most_register_interface() error: we previously assumed 'iface' could be null (see line 1285)

# https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/commit/?id=b276527539188f1f61c082ebef27803db93e536d
git remote add staging https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
git remote update staging
git checkout b276527539188f1f61c082ebef27803db93e536d
vim +/iface +1287 drivers/most/core.c

4d5f022f3a664e drivers/staging/most/core.c          Christian Gromm     2017-11-21  1279  int most_register_interface(struct most_interface *iface)
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1280  {
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1281  	unsigned int i;
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1282  	int id;
fcb7fad82e23f6 drivers/staging/most/core.c          Christian Gromm     2017-11-21  1283  	struct most_channel *c;
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1284  
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24 @1285  	if (!iface || !iface->enqueue || !iface->configure ||
                                                                                                    ^^^^^^

57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1286  	    !iface->poison_channel || (iface->num_channels > MAX_CHANNELS)) {
6a82c775812944 drivers/staging/most/core.c          Christian Gromm     2020-01-23 @1287  		dev_err(iface->dev, "Bad interface or channel overflow\n");
                                                                                                                ^^^^^^^^^^

Hopefully, we can just remove the NULL check?

4d5f022f3a664e drivers/staging/most/core.c          Christian Gromm     2017-11-21  1288  		return -EINVAL;
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1289  	}
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1290  
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1291  	id = ida_simple_get(&mdev_id, 0, 0, GFP_KERNEL);
57562a72414ca3 drivers/staging/most/mostcore/core.c Christian Gromm     2015-07-24  1292  	if (id < 0) {

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