CIFS: SMBD: Read correct returned data length for RDMA write (SMB read) I/O

This patch is for preparing upper layer doing SMB read via RDMA write.

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

Add the defition for memory registration to wdata and return the correct
length based on if RDMA write is used.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 29b5a9bd31288734d08badc8ae24854018ec1f55..678e638c1e6944d8c4aa763c7b189d4170784dd6 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -230,8 +230,14 @@ 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 */
@@ -1152,6 +1158,9 @@ struct cifs_readdata {
                                struct cifs_readdata *rdata,
                                struct iov_iter *iter);
        struct kvec                     iov[2];
+#ifdef CONFIG_CIFS_SMB_DIRECT
+       struct smbd_mr                  *mr;
+#endif
        unsigned int                    pagesz;
        unsigned int                    tailsz;
        unsigned int                    credits;

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 66d1ebfe75ddada9df891d2bc858d3371765fad1..49cf999f3d466a6f5ab4bc7acb49f4083c76d659 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1455,6 +1455,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
        struct cifs_readdata *rdata = mid->callback_data;
        char *buf = server->smallbuf;
        unsigned int buflen = get_rfc1002_length(buf) + 4;
+       bool use_rdma_mr = false;
 
        cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n",
                 __func__, mid->mid, rdata->offset, rdata->bytes);
@@ -1543,8 +1544,11 @@ 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) {
+#ifdef CONFIG_CIFS_SMB_DIRECT
+       use_rdma_mr = rdata->mr;
+#endif
+       data_len = server->ops->read_data_length(buf, use_rdma_mr);
+       if (!use_rdma_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 a723df3e01978cdca30afbf107772898ce66f33a..3d495e440c87c90386207e05fca529bcc9118784 100644 (file)
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -87,9 +87,11 @@ 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;
+       /* It's a bug reading remaining data for SMB1 packets */
+       WARN_ON(in_remaining);
        return (le16_to_cpu(rsp->DataLengthHigh) << 16) +
               le16_to_cpu(rsp->DataLength);
 }

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c8fa4c4ccc5012f7aef71c4d47abaf67798e1754..e3393ff5d458b34013fbb29e9b818992a596936b 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -957,9 +957,13 @@ 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);
 }
 
@@ -2421,6 +2425,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
        struct iov_iter iter;
        struct kvec iov;
        int length;
+       bool use_rdma_mr = false;
 
        if (shdr->Command != SMB2_READ) {
                cifs_dbg(VFS, "only big read responses are supported\n");
@@ -2447,7 +2452,10 @@ 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);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+       use_rdma_mr = rdata->mr;
+#endif
+       data_len = server->ops->read_data_length(buf, use_rdma_mr);
 
        if (data_offset < server->vals->read_rsp_size) {
                /*