cifs: break out 3rd receive phase into separate function

Move the entire 3rd phase of the receive codepath into a separate
function in preparation for the addition of a pluggable receive
function.

Reviewed-and-Tested-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 59 insertions, 42 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 52195bad5e6..f05dedda37c 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -705,6 +705,61 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
 }
 
 static int
+standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+        int length;
+        char *buf = server->smallbuf;
+        struct smb_hdr *smb_buffer = (struct smb_hdr *)buf;
+        unsigned int pdu_length = be32_to_cpu(smb_buffer->smb_buf_length);
+
+        /* make sure this will fit in a large buffer */
+        if (pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
+                cERROR(1, "SMB response too long (%u bytes)",
+                        pdu_length);
+                cifs_reconnect(server);
+                wake_up(&server->response_q);
+                return -EAGAIN;
+        }
+
+        /* switch to large buffer if too big for a small one */
+        if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
+                server->large_buf = true;
+                memcpy(server->bigbuf, server->smallbuf, server->total_read);
+                buf = server->bigbuf;
+                smb_buffer = (struct smb_hdr *)buf;
+        }
+
+        /* now read the rest */
+        length = read_from_socket(server,
+                          buf + sizeof(struct smb_hdr) - 1,
+                          pdu_length - sizeof(struct smb_hdr) + 1 + 4);
+        if (length < 0)
+                return length;
+        server->total_read += length;
+
+        dump_smb(smb_buffer, server->total_read);
+
+        /*
+         * We know that we received enough to get to the MID as we
+         * checked the pdu_length earlier. Now check to see
+         * if the rest of the header is OK. We borrow the length
+         * var for the rest of the loop to avoid a new stack var.
+         *
+         * 48 bytes is enough to display the header and a little bit
+         * into the payload for debugging purposes.
+         */
+        length = checkSMB(smb_buffer, smb_buffer->Mid, server->total_read);
+        if (length != 0)
+                cifs_dump_mem("Bad SMB: ", buf,
+                        min_t(unsigned int, server->total_read, 48));
+
+        if (mid)
+                handle_mid(mid, server, smb_buffer, length);
+
+        return length;
+}
+
+static int
 cifs_demultiplex_thread(void *p)
 {
         int length;
@@ -769,57 +824,19 @@ cifs_demultiplex_thread(void *p)
 
                 mid_entry = find_mid(server, smb_buffer);
 
-                if (pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
-                        cERROR(1, "SMB response too long (%u bytes)",
-                                pdu_length);
-                        cifs_reconnect(server);
-                        wake_up(&server->response_q);
+                length = standard_receive3(server, mid_entry);
+                if (length < 0)
                         continue;
-                }
 
-                /* else length ok */
-                if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
-                        server->large_buf = true;
-                        memcpy(server->bigbuf, server->smallbuf,
-                               server->total_read);
-                        smb_buffer = (struct smb_hdr *)server->bigbuf;
+                if (server->large_buf) {
                         buf = server->bigbuf;
+                        smb_buffer = (struct smb_hdr *)buf;
                 }
 
-                /* now read the rest */
-                length = read_from_socket(server,
-                                  buf + sizeof(struct smb_hdr) - 1,
-                                  pdu_length - sizeof(struct smb_hdr) + 1 + 4);
-                if (length < 0)
-                        continue;
-                server->total_read += length;
-
-                dump_smb(smb_buffer, server->total_read);
-
-                /*
-                 * We know that we received enough to get to the MID as we
-                 * checked the pdu_length earlier. Now check to see
-                 * if the rest of the header is OK. We borrow the length
-                 * var for the rest of the loop to avoid a new stack var.
-                 *
-                 * 48 bytes is enough to display the header and a little bit
-                 * into the payload for debugging purposes.
-                 */
-                length = checkSMB(smb_buffer, smb_buffer->Mid,
-                                  server->total_read);
-                if (length != 0)
-                        cifs_dump_mem("Bad SMB: ", buf,
-                                min_t(unsigned int, server->total_read, 48));
-
                 server->lstrp = jiffies;
-
                 if (mid_entry != NULL) {
-                        handle_mid(mid_entry, server, smb_buffer, length);
                         if (!mid_entry->multiRsp || mid_entry->multiEnd)
                                 mid_entry->callback(mid_entry);
-                } else if (length != 0) {
-                        /* response sanity checks failed */
-                        continue;
                 } else if (!is_valid_oplock_break(smb_buffer, server)) {
                         cERROR(1, "No task to wake, unknown frame received! "
                                    "NumMids %d", atomic_read(&midCount));