cifs: move file_lock off stack in cifs_push_posix_locks

struct file_lock is pretty large, so we really don't want that on the
stack in a potentially long call chain. Reorganize the arguments to
CIFSSMBPosixLock to eliminate the need for that.

Eliminate the get_flag and simply use a non-NULL pLockInfo to indicate
that this is a "get" operation. In order to do that, need to add a new
loff_t argument for the start_offset.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

3 files changed, 13 insertions, 16 deletions

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 0a6cbfe2761e..baa1b6dc838e 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -386,8 +386,9 @@ extern int CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
                         const bool waitFlag, const __u8 oplock_level);
 extern int CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
                         const __u16 smb_file_id, const __u32 netpid,
-                        const int get_flag, const __u64 len, struct file_lock *,
-                        const __u16 lock_type, const bool waitFlag);
+                        const loff_t start_offset, const __u64 len,
+                        struct file_lock *, const __u16 lock_type,
+                        const bool waitFlag);
 extern int CIFSSMBTDis(const int xid, struct cifs_tcon *tcon);
 extern int CIFSSMBEcho(struct TCP_Server_Info *server);
 extern int CIFSSMBLogoff(const int xid, struct cifs_ses *ses);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 684a0723021f..5659850f780a 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -2356,9 +2356,10 @@ CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
 
 int
 CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
-                const __u16 smb_file_id, const __u32 netpid, const int get_flag,
-                const __u64 len, struct file_lock *pLockData,
-                const __u16 lock_type, const bool waitFlag)
+                const __u16 smb_file_id, const __u32 netpid,
+                const loff_t start_offset, const __u64 len,
+                struct file_lock *pLockData, const __u16 lock_type,
+                const bool waitFlag)
 {
         struct smb_com_transaction2_sfi_req *pSMB  = NULL;
         struct smb_com_transaction2_sfi_rsp *pSMBr = NULL;
@@ -2372,9 +2373,6 @@ CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
 
         cFYI(1, "Posix Lock");
 
-        if (pLockData == NULL)
-                return -EINVAL;
-
         rc = small_smb_init(SMB_COM_TRANSACTION2, 15, tcon, (void **) &pSMB);
 
         if (rc)
@@ -2395,7 +2393,7 @@ CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
         pSMB->MaxDataCount = cpu_to_le16(1000); /* BB find max SMB from sess */
         pSMB->SetupCount = 1;
         pSMB->Reserved3 = 0;
-        if (get_flag)
+        if (pLockData)
                 pSMB->SubCommand = cpu_to_le16(TRANS2_QUERY_FILE_INFORMATION);
         else
                 pSMB->SubCommand = cpu_to_le16(TRANS2_SET_FILE_INFORMATION);
@@ -2417,7 +2415,7 @@ CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
                 pSMB->Timeout = 0;
 
         parm_data->pid = cpu_to_le32(netpid);
-        parm_data->start = cpu_to_le64(pLockData->fl_start);
+        parm_data->start = cpu_to_le64(start_offset);
         parm_data->length = cpu_to_le64(len);  /* normalize negative numbers */
 
         pSMB->DataOffset = cpu_to_le16(offset);
@@ -2441,7 +2439,7 @@ CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
 
         if (rc) {
                 cFYI(1, "Send error in Posix Lock = %d", rc);
-        } else if (get_flag) {
+        } else if (pLockData) {
                 /* lock structure can be returned on get */
                 __u16 data_offset;
                 __u16 data_count;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index dd28caa0a5ce..e9a8ac0047c7 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1039,12 +1039,10 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
         unlock_flocks();
 
         list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
-                struct file_lock tmp_lock;
                 int stored_rc;
 
-                tmp_lock.fl_start = lck->offset;
                 stored_rc = CIFSSMBPosixLock(xid, tcon, lck->netfid, lck->pid,
-                                             0, lck->length, &tmp_lock,
+                                             lck->offset, lck->length, NULL,
                                              lck->type, 0);
                 if (stored_rc)
                         rc = stored_rc;
@@ -1159,7 +1157,7 @@ cifs_getlk(struct file *file, struct file_lock *flock, __u32 type,
                 else
                         posix_lock_type = CIFS_WRLCK;
                 rc = CIFSSMBPosixLock(xid, tcon, netfid, current->tgid,
-                                      1 /* get */, length, flock,
+                                      flock->fl_start, length, flock,
                                       posix_lock_type, wait_flag);
                 return rc;
         }
@@ -1353,7 +1351,7 @@ cifs_setlk(struct file *file,  struct file_lock *flock, __u32 type,
                         posix_lock_type = CIFS_UNLCK;
 
                 rc = CIFSSMBPosixLock(xid, tcon, netfid, current->tgid,
-                                      0 /* set */, length, flock,
+                                      flock->fl_start, length, NULL,
                                       posix_lock_type, wait_flag);
                 goto out;
         }