CIFS: Simplify byte range locking code

Split cifs_lock into several functions and let CIFSSMBLock get pid
as an argument.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/cifsglob.h

@@ -492,6 +492,7 @@ struct cifsLockInfo {
 	struct list_head llist;	/* pointer to next cifsLockInfo */
 	__u64 offset;
 	__u64 length;
+	__u32 pid;
 	__u8 type;
 };
 

fs/cifs/cifsproto.h

@@ -361,7 +361,7 @@ extern int CIFSGetSrvInodeNumber(const int xid, struct cifs_tcon *tcon,
 			int remap_special_chars);
 
 extern int CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
-			const __u16 netfid, const __u64 len,
+			const __u16 netfid, const __u32 netpid, const __u64 len,
 			const __u64 offset, const __u32 numUnlock,
 			const __u32 numLock, const __u8 lockType,
 			const bool waitFlag, const __u8 oplock_level);

fs/cifs/cifssmb.c

@@ -1963,7 +1963,7 @@ CIFSSMBWrite2(const int xid, struct cifs_io_parms *io_parms,
 
 int
 CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
-	    const __u16 smb_file_id, const __u64 len,
+	    const __u16 smb_file_id, const __u32 netpid, const __u64 len,
 	    const __u64 offset, const __u32 numUnlock,
 	    const __u32 numLock, const __u8 lockType,
 	    const bool waitFlag, const __u8 oplock_level)
@@ -1999,7 +1999,7 @@ CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
 	pSMB->Fid = smb_file_id; /* netfid stays le */
 
 	if ((numLock != 0) || (numUnlock != 0)) {
-		pSMB->Locks[0].Pid = cpu_to_le16(current->tgid);
+		pSMB->Locks[0].Pid = cpu_to_le16(netpid);
 		/* BB where to store pid high? */
 		pSMB->Locks[0].LengthLow = cpu_to_le32((u32)len);
 		pSMB->Locks[0].LengthHigh = cpu_to_le32((u32)(len>>32));