cdrom: gdrom: deallocate struct gdrom_unit fields in remove_gdrom

stable inclusion
from stable-5.10.40
commit 9285808072d4aeabdf710187acae5e09e71157e4
bugzilla: 51882
CVE: NA

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

commit d03d1021 upstream.

The fields, "toc" and "cd_info", of "struct gdrom_unit gd" are allocated
in "probe_gdrom()". Prevent a memory leak by making sure "gd.cd_info" is
deallocated in the "remove_gdrom()" function.

Also prevent double free of the field "gd.toc" by moving it from the
module's exit function to "remove_gdrom()". This is because, in
"probe_gdrom()", the function makes sure to deallocate "gd.toc" in case
of any errors, so the exit function invoked later would again free
"gd.toc".

The patch also maintains consistency by deallocating the above mentioned
fields in "remove_gdrom()" along with another memory allocated field
"gd.disk".

Suggested-by: Jens Axboe <axboe@kernel.dk>
Cc: Peter Rosin <peda@axentia.se>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Atul Gopinathan <atulgopinathan@gmail.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-28-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>