[PATCH 1/1] fix memory leak during adapter release by destroying gid_pn_req

[Nihar Panda <niharp@linux.ibm.com>]

From: Benjamin Block <bblock@linux.ibm.com>

When releasing an adapter we don't free the mempool `gid_pn_req` that is
allocated during the enqueue. This leaks memory:

  unreferenced object 0xd8d29297de700 (size 256):
    comm "(udev-worker)", pid 2105, jiffies 4294945794
    hex dump (first 32 bytes):
      00 00 00 00 de ad 4e ad ff ff ff ff 00 00 00 00  ......N.........
      ff ff ff ff ff ff ff ff 00 0d c4 5f 67 9d 99 e0  ..........._g...
    backtrace (crc 4a5b5da2):
      [<000dc45f64da418c>] kmemleak_alloc+0x6c/0xa0
      [<000dc45f62b430aa>] __kmalloc_cache_node_noprof+0x36a/0x4d0
      [<000dc45f629a535a>] mempool_create_node_noprof+0xaa/0x150
      [<000dc45ee2c065e6>] zfcp_allocate_low_mem_buffers+0x96/0x370 [zfcp]
      [<000dc45ee2c070f8>] zfcp_adapter_enqueue+0x598/0xd40 [zfcp]
      [<000dc45ee2c08eb0>] zfcp_ccw_set_online+0x160/0x210 [zfcp]
      [<000dc45f643d4762>] ccw_device_set_online+0x232/0xd80
      [<000dc45f643d53d4>] online_store_recog_and_online+0x124/0x390
      [<000dc45f643d8238>] online_store+0x298/0x5b0
      [<000dc45f62eb0a04>] kernfs_fop_write_iter+0x2c4/0x480
      [<000dc45f62c81150>] new_sync_write+0x370/0x4b0
      [<000dc45f62c87abe>] vfs_write+0x43e/0x5b0
      [<000dc45f62c87ff4>] ksys_write+0x114/0x1f0
      [<000dc45f621c4a16>] do_syscall+0x2f6/0x430
      [<000dc45f64d9d5d8>] __do_syscall+0xc8/0x1c0
      [<000dc45f64dc2224>] system_call+0x74/0xa0

Fix this by destroying the mempool during the adapter's release.

Fixes: 799b76d09aee ("[SCSI] zfcp: Decouple gid_pn requests from erp")
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Tested-by: M Nikhil <nikh1092@linux.ibm.com>
Acked-by: M Nikhil <nikh1092@linux.ibm.com>
Reviewed-by: Chinmaya Kajagar <chinmayk@linux.ibm.com>
Reviewed-by: Nihar Panda <niharp@linux.ibm.com>
---
 drivers/s390/scsi/zfcp_aux.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 8ff7db7921b5..fea573e00f9d 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -253,6 +253,7 @@ static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
 {
 	mempool_destroy(adapter->pool.erp_req);
+	mempool_destroy(adapter->pool.gid_pn_req);
 	mempool_destroy(adapter->pool.scsi_req);
 	mempool_destroy(adapter->pool.scsi_abort);
 	mempool_destroy(adapter->pool.qtcb_pool);
-- 
2.53.0