[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 0abfbf4..c96a148 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: