[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 3c628bf667a5..b4f7b9859e3b 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