[Patch v2 16/19] CIFS: SMBD: Read correct returned data length for RDMA write (SMB READ) I/O

[Long Li]

From: Long Li <lon...@microsoft.com>

When RDMA write is used for SMB READ, the returned data length is returned in 
DataRemaining in the response packet. Reading it properly by adding a parameter 
to specifiy where the returned data length is.

Signed-off-by: Long Li <lon...@microsoft.com>
---
 fs/cifs/cifsglob.h | 10 ++++++++--
 fs/cifs/cifssmb.c  |  4 ++--
 fs/cifs/smb1ops.c  |  2 +-
 fs/cifs/smb2ops.c  |  8 ++++++--
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index dcd2b63..d391767 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -231,8 +231,14 @@ struct smb_version_operations {
        __u64 (*get_next_mid)(struct TCP_Server_Info *);
        /* data offset from read response message */
        unsigned int (*read_data_offset)(char *);
-       /* data length from read response message */
-       unsigned int (*read_data_length)(char *);
+       /*
+        * Data length from read response message
+        * When in_remaining is true, the returned data length is in
+        * message field DataRemaining for out-of-band data read (e.g through
+        * Memory Registration RDMA write in SMBD).
+        * Otherwise, the returned data length is in message field DataLength.
+        */
+       unsigned int (*read_data_length)(char *, bool in_remaining);
        /* map smb to linux error */
        int (*map_error)(char *, bool);
        /* find mid corresponding to the response message */
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index fbb0d4c..9030fb5 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1523,8 +1523,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct 
mid_q_entry *mid)
                 rdata->iov[0].iov_base, server->total_read);
 
        /* how much data is in the response? */
-       data_len = server->ops->read_data_length(buf);
-       if (data_offset + data_len > buflen) {
+       data_len = server->ops->read_data_length(buf, rdata->mr);
+       if (!rdata->mr && (data_offset + data_len > buflen)) {
                /* data_len is corrupt -- discard frame */
                rdata->result = -EIO;
                return cifs_readv_discard(server, mid);
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index a723df3..27a8280 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -87,7 +87,7 @@ cifs_read_data_offset(char *buf)
 }
 
 static unsigned int
-cifs_read_data_length(char *buf)
+cifs_read_data_length(char *buf, bool in_remaining)
 {
        READ_RSP *rsp = (READ_RSP *)buf;
        return (le16_to_cpu(rsp->DataLengthHigh) << 16) +
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index e67f5f0..4067629 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -747,9 +747,13 @@ smb2_read_data_offset(char *buf)
 }
 
 static unsigned int
-smb2_read_data_length(char *buf)
+smb2_read_data_length(char *buf, bool in_remaining)
 {
        struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
+
+       if (in_remaining)
+               return le32_to_cpu(rsp->DataRemaining);
+
        return le32_to_cpu(rsp->DataLength);
 }
 
@@ -2181,7 +2185,7 @@ handle_read_data(struct TCP_Server_Info *server, struct 
mid_q_entry *mid,
        }
 
        data_offset = server->ops->read_data_offset(buf) + 4;
-       data_len = server->ops->read_data_length(buf);
+       data_len = server->ops->read_data_length(buf, rdata->mr);
 
        if (data_offset < server->vals->read_rsp_size) {
                /*
-- 
2.7.4