CIFS: Separate SMB2 sync header processing

Do not process RFC1001 length in smb2_hdr_assemble() because
it is not a part of SMB2 header. This allows to cleanup the code
and adds a possibility combine several SMB2 packets into one
for compounding.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>

2 files changed, 35 insertions, 20 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 438c4b108c07..f6ba2c03f7cc 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -79,25 +79,9 @@ static const int smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
 
 
 static void
-smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
+smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
                   const struct cifs_tcon *tcon)
 {
-        struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
-        struct smb2_sync_hdr *shdr = get_sync_hdr(hdr);
-        char *temp = (char *)hdr;
-        /* lookup word count ie StructureSize from table */
-        __u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_cmd)];
-
-        /*
-         * smaller than SMALL_BUFFER_SIZE but bigger than fixed area of
-         * largest operations (Create)
-         */
-        memset(temp, 0, 256);
-
-        /* Note this is only network field converted to big endian */
-        hdr->smb2_buf_length =
-                        cpu_to_be32(parmsize + sizeof(struct smb2_sync_hdr));
-
         shdr->ProtocolId = SMB2_PROTO_NUMBER;
         shdr->StructureSize = cpu_to_le16(64);
         shdr->Command = smb2_cmd;
@@ -149,7 +133,6 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
         if (tcon->ses && tcon->ses->server && tcon->ses->server->sign)
                 shdr->Flags |= SMB2_FLAGS_SIGNED;
 out:
-        pdu->StructureSize2 = cpu_to_le16(parmsize);
         return;
 }
 
@@ -290,6 +273,26 @@ out:
         return rc;
 }
 
+static void
+fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
+               unsigned int *total_len)
+{
+        struct smb2_sync_pdu *spdu = (struct smb2_sync_pdu *)buf;
+        /* lookup word count ie StructureSize from table */
+        __u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_command)];
+
+        /*
+         * smaller than SMALL_BUFFER_SIZE but bigger than fixed area of
+         * largest operations (Create)
+         */
+        memset(buf, 0, 256);
+
+        smb2_hdr_assemble(&spdu->sync_hdr, smb2_command, tcon);
+        spdu->StructureSize2 = cpu_to_le16(parmsize);
+
+        *total_len = parmsize + sizeof(struct smb2_sync_hdr);
+}
+
 /*
  * Allocate and return pointer to an SMB request hdr, and set basic
  * SMB information in the SMB header. If the return code is zero, this
@@ -299,7 +302,9 @@ static int
 small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
                 void **request_buf)
 {
-        int rc = 0;
+        int rc;
+        unsigned int total_len;
+        struct smb2_pdu *pdu;
 
         rc = smb2_reconnect(smb2_command, tcon);
         if (rc)
@@ -312,7 +317,12 @@ small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
                 return -ENOMEM;
         }
 
-        smb2_hdr_assemble((struct smb2_hdr *) *request_buf, smb2_command, tcon);
+        pdu = (struct smb2_pdu *)(*request_buf);
+
+        fill_small_buf(smb2_command, tcon, get_sync_hdr(pdu), &total_len);
+
+        /* Note this is only network field converted to big endian */
+        pdu->hdr.smb2_buf_length = cpu_to_be32(total_len);
 
         if (tcon != NULL) {
 #ifdef CONFIG_CIFS_STATS2
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 8dd24b73d974..052342da4844 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -117,6 +117,11 @@ struct smb2_sync_hdr {
         __u8   Signature[16];
 } __packed;
 
+struct smb2_sync_pdu {
+        struct smb2_sync_hdr sync_hdr;
+        __le16 StructureSize2; /* size of wct area (varies, request specific) */
+} __packed;
+
 struct smb2_hdr {
         __be32 smb2_buf_length; /* big endian on wire */
                                 /* length is only two or three bytes - with */