From ec637e3ffb6b978143652477c7c5f96c9519b691 Mon Sep 17 00:00:00 2001 From: Steve French Date: Mon, 12 Dec 2005 20:53:18 -0800 Subject: [CIFS] Avoid extra large buffer allocation (and memcpy) in cifs_readpages Signed-off-by: Steve French --- fs/cifs/cifssmb.c | 93 ++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 58 insertions(+), 35 deletions(-) (limited to 'fs/cifs/cifssmb.c') diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 3565d3bf2e32..1620991cd4d2 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -958,21 +958,19 @@ openRetry: return rc; } -/* If no buffer passed in, then caller wants to do the copy - as in the case of readpages so the SMB buffer must be - freed by the caller */ - int CIFSSMBRead(const int xid, struct cifsTconInfo *tcon, - const int netfid, const unsigned int count, - const __u64 lseek, unsigned int *nbytes, char **buf) + const int netfid, const unsigned int count, + const __u64 lseek, unsigned int *nbytes, char **buf, + int * pbuf_type) { int rc = -EACCES; READ_REQ *pSMB = NULL; READ_RSP *pSMBr = NULL; char *pReadData = NULL; - int bytes_returned; int wct; + int resp_buf_type = 0; + struct kvec iov[1]; cFYI(1,("Reading %d bytes on fid %d",count,netfid)); if(tcon->ses->capabilities & CAP_LARGE_FILES) @@ -981,8 +979,7 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon, wct = 10; /* old style read */ *nbytes = 0; - rc = smb_init(SMB_COM_READ_ANDX, wct, tcon, (void **) &pSMB, - (void **) &pSMBr); + rc = small_smb_init(SMB_COM_READ_ANDX, wct, tcon, (void **) &pSMB); if (rc) return rc; @@ -990,13 +987,13 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon, if (tcon->ses->server == NULL) return -ECONNABORTED; - pSMB->AndXCommand = 0xFF; /* none */ + pSMB->AndXCommand = 0xFF; /* none */ pSMB->Fid = netfid; pSMB->OffsetLow = cpu_to_le32(lseek & 0xFFFFFFFF); if(wct == 12) pSMB->OffsetHigh = cpu_to_le32(lseek >> 32); - else if((lseek >> 32) > 0) /* can not handle this big offset for old */ - return -EIO; + else if((lseek >> 32) > 0) /* can not handle this big offset for old */ + return -EIO; pSMB->Remaining = 0; pSMB->MaxCount = cpu_to_le16(count & 0xFFFF); @@ -1005,14 +1002,18 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon, pSMB->ByteCount = 0; /* no need to do le conversion since 0 */ else { /* old style read */ - struct smb_com_readx_req * pSMBW = + struct smb_com_readx_req * pSMBW = (struct smb_com_readx_req *)pSMB; - pSMBW->ByteCount = 0; + pSMBW->ByteCount = 0; } - - rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB, - (struct smb_hdr *) pSMBr, &bytes_returned, 0); + + iov[0].iov_base = (char *)pSMB; + iov[0].iov_len = pSMB->hdr.smb_buf_length + 4; + rc = SendReceive2(xid, tcon->ses, iov, + 1 /* num iovecs */, + &resp_buf_type, 0); cifs_stats_inc(&tcon->num_reads); + pSMBr = (READ_RSP *)iov[0].iov_base; if (rc) { cERROR(1, ("Send error in read = %d", rc)); } else { @@ -1022,33 +1023,43 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon, *nbytes = data_length; /*check that DataLength would not go beyond end of SMB */ - if ((data_length > CIFSMaxBufSize) + if ((data_length > CIFSMaxBufSize) || (data_length > count)) { cFYI(1,("bad length %d for count %d",data_length,count)); rc = -EIO; *nbytes = 0; } else { - pReadData = - (char *) (&pSMBr->hdr.Protocol) + + pReadData = (char *) (&pSMBr->hdr.Protocol) + le16_to_cpu(pSMBr->DataOffset); -/* if(rc = copy_to_user(buf, pReadData, data_length)) { - cERROR(1,("Faulting on read rc = %d",rc)); - rc = -EFAULT; - }*/ /* can not use copy_to_user when using page cache*/ +/* if(rc = copy_to_user(buf, pReadData, data_length)) { + cERROR(1,("Faulting on read rc = %d",rc)); + rc = -EFAULT; + }*/ /* can not use copy_to_user when using page cache*/ if(*buf) - memcpy(*buf,pReadData,data_length); + memcpy(*buf,pReadData,data_length); } } - if(*buf) - cifs_buf_release(pSMB); - else - *buf = (char *)pSMB; - /* Note: On -EAGAIN error only caller can retry on handle based calls + cifs_small_buf_release(pSMB); + if(*buf) { + if(resp_buf_type == CIFS_SMALL_BUFFER) + cifs_small_buf_release(iov[0].iov_base); + else if(resp_buf_type == CIFS_LARGE_BUFFER) + cifs_buf_release(iov[0].iov_base); + } else /* return buffer to caller to free */ /* BB FIXME how do we tell caller if it is not a large buffer */ { + *buf = iov[0].iov_base; + if(resp_buf_type == CIFS_SMALL_BUFFER) + *pbuf_type = CIFS_SMALL_BUFFER; + else if(resp_buf_type == CIFS_LARGE_BUFFER) + *pbuf_type = CIFS_LARGE_BUFFER; + } + + /* Note: On -EAGAIN error only caller can retry on handle based calls since file handle passed in no longer valid */ return rc; } + int CIFSSMBWrite(const int xid, struct cifsTconInfo *tcon, const int netfid, const unsigned int count, @@ -1163,10 +1174,10 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon, { int rc = -EACCES; WRITE_REQ *pSMB = NULL; - int bytes_returned, wct; + int wct; int smb_hdr_len; + int resp_buf_type = 0; - /* BB removeme BB */ cFYI(1,("write2 at %lld %d bytes", (long long)offset, count)); if(tcon->ses->capabilities & CAP_LARGE_FILES) @@ -1209,22 +1220,34 @@ CIFSSMBWrite2(const int xid, struct cifsTconInfo *tcon, pSMBW->ByteCount = cpu_to_le16(count + 5); } iov[0].iov_base = pSMB; - iov[0].iov_len = smb_hdr_len + 4; + if(wct == 14) + iov[0].iov_len = smb_hdr_len + 4; + else /* wct == 12 pad bigger by four bytes */ + iov[0].iov_len = smb_hdr_len + 8; + - rc = SendReceive2(xid, tcon->ses, iov, n_vec + 1, &bytes_returned, + rc = SendReceive2(xid, tcon->ses, iov, n_vec + 1, &resp_buf_type, long_op); cifs_stats_inc(&tcon->num_writes); if (rc) { cFYI(1, ("Send error Write2 = %d", rc)); *nbytes = 0; + } else if(resp_buf_type == 0) { + /* presumably this can not happen, but best to be safe */ + rc = -EIO; + *nbytes = 0; } else { - WRITE_RSP * pSMBr = (WRITE_RSP *)pSMB; + WRITE_RSP * pSMBr = (WRITE_RSP *)iov[0].iov_base; *nbytes = le16_to_cpu(pSMBr->CountHigh); *nbytes = (*nbytes) << 16; *nbytes += le16_to_cpu(pSMBr->Count); } cifs_small_buf_release(pSMB); + if(resp_buf_type == CIFS_SMALL_BUFFER) + cifs_small_buf_release(iov[0].iov_base); + else if(resp_buf_type == CIFS_LARGE_BUFFER) + cifs_buf_release(iov[0].iov_base); /* Note: On -EAGAIN error only caller can retry on handle based calls since file handle passed in no longer valid */ -- cgit v1.2.3