test_firmware: fix a memory leak with reqs buffer

stable inclusion
from stable-v5.10.185
commit 539c387f0bb9c4a13ccd50133103a7b38db33b2b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8L5XP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=539c387f0bb9c4a13ccd50133103a7b38db33b2b



--------------------------------

[ Upstream commit be37bed7 ]

Dan Carpenter spotted that test_fw_config->reqs will be leaked if
trigger_batched_requests_store() is called two or more times.
The same appears with trigger_batched_requests_async_store().

This bug wasn't trigger by the tests, but observed by Dan's visual
inspection of the code.

The recommended workaround was to return -EBUSY if test_fw_config->reqs
is already allocated.

Fixes: 7feebfa4 ("test_firmware: add support for request_firmware_into_buf")
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russ Weight <russell.h.weight@intel.com>
Cc: Tianfei Zhang <tianfei.zhang@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-kselftest@vger.kernel.org
Cc: stable@vger.kernel.org # v5.4
Suggested-by: Dan Carpenter <error27@gmail.com>
Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230509084746.48259-2-mirsad.todorovac@alu.unizg.hr


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>