[CIFS] Avoid extra large buffer allocation (and memcpy) in cifs_readpages

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 19 insertions, 19 deletions

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 0abfbf4e4a49..c96a148c39b2 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -298,7 +298,7 @@ smb_send2(struct socket *ssocket, struct kvec *iov, int n_vec,
 
 int
 SendReceive2(const unsigned int xid, struct cifsSesInfo *ses, 
-             struct kvec *iov, int n_vec, int *pbytes_returned,
+             struct kvec *iov, int n_vec, int * pRespBufType /* ret */, 
              const int long_op)
 {
         int rc = 0;
@@ -306,6 +306,8 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
         unsigned long timeout;
         struct mid_q_entry *midQ;
         struct smb_hdr *in_buf = iov[0].iov_base;
+        
+        *pRespBufType = CIFS_NO_BUFFER;  /* no response buf yet */
 
         if (ses == NULL) {
                 cERROR(1,("Null smb session"));
@@ -491,23 +493,20 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
                 if (midQ->resp_buf && 
                         (midQ->midState == MID_RESPONSE_RECEIVED)) {
 
-                        in_buf->smb_buf_length = receive_len;
-                        if(receive_len > 500) {
-                                /* use multiple buffers on way out */
-                        } else { 
-                                memcpy((char *)in_buf + 4,
-                                        (char *)midQ->resp_buf + 4,
-                                        receive_len);
-                                iov[0].iov_len = receive_len + 4;
-                                iov[1].iov_len = 0;
-                        }
+                        iov[0].iov_base = (char *)midQ->resp_buf;
+                        if(midQ->largeBuf)
+                                *pRespBufType = CIFS_LARGE_BUFFER;
+                        else
+                                *pRespBufType = CIFS_SMALL_BUFFER;
+                        iov[0].iov_len = receive_len + 4;
+                        iov[1].iov_len = 0;
 
-                        dump_smb(in_buf, 80);
+                        dump_smb(midQ->resp_buf, 80);
                         /* convert the length into a more usable form */
                         if((receive_len > 24) &&
                            (ses->server->secMode & (SECMODE_SIGN_REQUIRED |
                                         SECMODE_SIGN_ENABLED))) {
-                                rc = cifs_verify_signature(in_buf,
+                                rc = cifs_verify_signature(midQ->resp_buf,
                                                 ses->server->mac_signing_key,
                                                 midQ->sequence_number+1);
                                 if(rc) {
@@ -516,18 +515,19 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
                                 }
                         }
 
-                        *pbytes_returned = in_buf->smb_buf_length;
-
                         /* BB special case reconnect tid and uid here? */
                         /* BB special case Errbadpassword and pwdexpired here */
-                        rc = map_smb_to_linux_error(in_buf);
+                        rc = map_smb_to_linux_error(midQ->resp_buf);
 
                         /* convert ByteCount if necessary */
                         if (receive_len >=
                             sizeof (struct smb_hdr) -
                             4 /* do not count RFC1001 header */  +
-                            (2 * in_buf->WordCount) + 2 /* bcc */ )
-                                BCC(in_buf) = le16_to_cpu(BCC_LE(in_buf));
+                            (2 * midQ->resp_buf->WordCount) + 2 /* bcc */ )
+                                BCC(midQ->resp_buf) = 
+                                        le16_to_cpu(BCC_LE(midQ->resp_buf));
+                        midQ->resp_buf = NULL;  /* mark it so will not be freed
+                                                by DeleteMidQEntry */
                 } else {
                         rc = -EIO;
                         cFYI(1,("Bad MID state?"));
@@ -793,7 +793,7 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
                                 BCC(out_buf) = le16_to_cpu(BCC_LE(out_buf));
                 } else {
                         rc = -EIO;
-                        cERROR(1,("Bad MID state? "));
+                        cERROR(1,("Bad MID state?"));
                 }
         }
 cifs_no_response_exit: