cifs: remove unnecessary locking around sequence_number

The server->sequence_number is already protected by the srv_mutex. The
GlobalMid_lock is unneeded here.

Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

2 files changed, 3 insertions, 5 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index f856732161ab..66f3d50d0676 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -72,6 +72,7 @@ static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,
         return 0;
 }
 
+/* must be called with server->srv_mutex held */
 int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
                   __u32 *pexpected_response_sequence_number)
 {
@@ -84,14 +85,12 @@ int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
                 return rc;
 
-        spin_lock(&GlobalMid_Lock);
         cifs_pdu->Signature.Sequence.SequenceNumber =
                         cpu_to_le32(server->sequence_number);
         cifs_pdu->Signature.Sequence.Reserved = 0;
 
         *pexpected_response_sequence_number = server->sequence_number++;
         server->sequence_number++;
-        spin_unlock(&GlobalMid_Lock);
 
         rc = cifs_calculate_signature(cifs_pdu, server, smb_signature);
         if (rc)
@@ -149,6 +148,7 @@ static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
         return rc;
 }
 
+/* must be called with server->srv_mutex held */
 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
                    __u32 *pexpected_response_sequence_number)
 {
@@ -162,14 +162,12 @@ int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
         if ((cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) == 0)
                 return rc;
 
-        spin_lock(&GlobalMid_Lock);
         cifs_pdu->Signature.Sequence.SequenceNumber =
                                 cpu_to_le32(server->sequence_number);
         cifs_pdu->Signature.Sequence.Reserved = 0;
 
         *pexpected_response_sequence_number = server->sequence_number++;
         server->sequence_number++;
-        spin_unlock(&GlobalMid_Lock);
 
         rc = cifs_calc_signature2(iov, n_vec, server, smb_signature);
         if (rc)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index dfd2d46275ab..e6590e69fb0e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -207,7 +207,7 @@ struct TCP_Server_Info {
         char cryptkey[CIFS_CRYPTO_KEY_SIZE]; /* used by ntlm, ntlmv2 etc */
         /* 16th byte of RFC1001 workstation name is always null */
         char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
-        __u32 sequence_number; /* needed for CIFS PDU signature */
+        __u32 sequence_number; /* for signing, protected by srv_mutex */
         struct session_key session_key;
         unsigned long lstrp; /* when we got last response from this server */
         u16 dialect; /* dialect index that server chose */