[CIFS] CIFS writepage improvements - eliminate double copy

Signed-off-by: Steve French (sfrench@us.ibm.com)

1 files changed, 36 insertions, 21 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 3c628bf667a..b4f7b9859e3 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -951,56 +951,69 @@ CIFSSMBWrite(const int xid, struct cifsTconInfo *tcon,
 }
 
 #ifdef CONFIG_CIFS_EXPERIMENTAL
-int CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
+int
+CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 	     const int netfid, const unsigned int count,
-	     const __u64 offset, unsigned int *nbytes, const char __user *buf,
+	     const __u64 offset, unsigned int *nbytes, const char *buf,
 	     const int long_op)
 {
 	int rc = -EACCES;
 	WRITE_REQ *pSMB = NULL;
-	WRITE_RSP *pSMBr = NULL;
-	/*int bytes_returned;*/
-	unsigned bytes_sent;
+	int bytes_returned;
+	int smb_hdr_len;
+	__u32 bytes_sent;
 	__u16 byte_count;
 
+	cERROR(1,("write2 at %lld %d bytes",offset,count)); /* BB removeme BB */
 	rc = small_smb_init(SMB_COM_WRITE_ANDX, 14, tcon, (void **) &pSMB);
-    
 	if (rc)
 		return rc;
-	
-	pSMBr = (WRITE_RSP *)pSMB; /* BB removeme BB */
-
 	/* tcon and ses pointer are checked in smb_init */
 	if (tcon->ses->server == NULL)
 		return -ECONNABORTED;
 
-	pSMB->AndXCommand = 0xFF; /* none */
+	pSMB->AndXCommand = 0xFF;	/* none */
 	pSMB->Fid = netfid;
 	pSMB->OffsetLow = cpu_to_le32(offset & 0xFFFFFFFF);
 	pSMB->OffsetHigh = cpu_to_le32(offset >> 32);
 	pSMB->Reserved = 0xFFFFFFFF;
 	pSMB->WriteMode = 0;
 	pSMB->Remaining = 0;
-	bytes_sent = (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE) & ~0xFF;
+
+	/* Can increase buffer size if buffer is big enough in some cases - ie 
+	can send more if LARGE_WRITE_X capability returned by the server and if
+	our buffer is big enough or if we convert to iovecs on socket writes
+	and eliminate the copy to the CIFS buffer */
+	if(tcon->ses->capabilities & CAP_LARGE_WRITE_X) {
+		bytes_sent = min_t(const unsigned int, CIFSMaxBufSize, count);
+	} else {
+		bytes_sent = (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE)
+			 & ~0xFF;
+	}
+
 	if (bytes_sent > count)
 		bytes_sent = count;
-	pSMB->DataLengthHigh = 0;
 	pSMB->DataOffset =
 	    cpu_to_le16(offsetof(struct smb_com_write_req,Data) - 4);
 
-	byte_count = bytes_sent + 1 /* pad */ ;
-	pSMB->DataLengthLow = cpu_to_le16(bytes_sent);
-	pSMB->DataLengthHigh = 0;
-	pSMB->hdr.smb_buf_length += byte_count;
+	byte_count = bytes_sent + 1 /* pad */ ; /* BB fix this for sends > 64K */
+	pSMB->DataLengthLow = cpu_to_le16(bytes_sent & 0xFFFF);
+	pSMB->DataLengthHigh = cpu_to_le16(bytes_sent >> 16);
+	smb_hdr_len = pSMB->hdr.smb_buf_length + 1; /* hdr + 1 byte pad */
+	pSMB->hdr.smb_buf_length += bytes_sent+1;
 	pSMB->ByteCount = cpu_to_le16(byte_count);
 
-/*	rc = SendReceive2(xid, tcon->ses, (struct smb_hdr *) pSMB,
-			 (struct smb_hdr *) pSMBr, buf, buflen, &bytes_returned, long_op); */  /* BB fixme BB */
+	rc = SendReceive2(xid, tcon->ses, (struct smb_hdr *) pSMB, smb_hdr_len,
+			  buf, bytes_sent, &bytes_returned, long_op);
 	if (rc) {
-		cFYI(1, ("Send error in write2 (large write) = %d", rc));
+		cFYI(1, ("Send error in write = %d", rc));
 		*nbytes = 0;
-	} else
-		*nbytes = le16_to_cpu(pSMBr->Count);
+	} else {
+		WRITE_RSP * pSMBr = (WRITE_RSP *)pSMB;
+		*nbytes = le16_to_cpu(pSMBr->CountHigh);
+		*nbytes = (*nbytes) << 16;
+		*nbytes += le16_to_cpu(pSMBr->Count);
+	}
 
 	cifs_small_buf_release(pSMB);
 
@@ -1009,6 +1022,8 @@ int CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon,
 
 	return rc;
 }
+
+
 #endif /* CIFS_EXPERIMENTAL */
 
 int