cifs: fix warning when destroy 'cifs_io_request_pool'

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: cifs: fix warning when destroy 'cifs_io_request_pool' There's a issue as follows: WARNING: CPU: 1 PID: 27826 at mm/slub.c:4698 free_large_kmalloc+0xac/0xe0 RIP: 0010:free_large_kmalloc+0xac/0xe0 Call Trace: <TASK> ? __warn+0xea/0x330 mempool_destroy+0x13f/0x1d0 init_cifs+0xa50/0xff0 [cifs] do_one_initcall+0xdc/0x550 do_init_module+0x22d/0x6b0 load_module+0x4e96/0x5ff0 init_module_from_file+0xcd/0x130 idempotent_init_module+0x330/0x620 __x64_sys_finit_module+0xb3/0x110 do_syscall_64+0xc1/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Obviously, 'cifs_io_request_pool' is not created by mempool_create(). So just use mempool_exit() to revert 'cifs_io_request_pool'.

References

• https://git.kernel.org/stable/c/726416a253c51037636ecc65ad3dada3d02dcaea
• https://git.kernel.org/stable/c/2ce1007f42b8a6a0814386cb056feb28dc6d6091