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cifs: smbd: Avoid allocating iov on the stack 

It's not necessary to allocate another iov when going through the buffers
in smbd_send() through RDMA send.

Remove it to reduce stack size.

Thanks to Matt for spotting a printk typo in the earlier version of this.

CC: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Long Li <longli@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Long Li 2018-04-17 12:17:07 -07:00 committed by Steve French
parent bb4c041947
commit 8bcda1d2a7
1 changed files with 12 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
fs/cifs/smbdirect.c
View File

@ -2086,7 +2086,7 @@ int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
int start, i, j;
int max_iov_size =
info->max_send_size - sizeof(struct smbd_data_transfer);
struct kvec iov[SMBDIRECT_MAX_SGE];
struct kvec *iov;
int rc;
info->smbd_send_pending++;
@ -2096,32 +2096,20 @@ int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
}
/*
* This usually means a configuration error
* We use RDMA read/write for packet size > rdma_readwrite_threshold
* as long as it's properly configured we should never get into this
* situation
*/
if (rqst->rq_nvec + rqst->rq_npages > SMBDIRECT_MAX_SGE) {
log_write(ERR, "maximum send segment %x exceeding %x\n",
rqst->rq_nvec + rqst->rq_npages, SMBDIRECT_MAX_SGE);
rc = -EINVAL;
goto done;
}
/*
* Remove the RFC1002 length defined in MS-SMB2 section 2.1
* It is used only for TCP transport
* Skip the RFC1002 length defined in MS-SMB2 section 2.1
* It is used only for TCP transport in the iov[0]
* In future we may want to add a transport layer under protocol
* layer so this will only be issued to TCP transport
*/
iov[0].iov_base = (char *)rqst->rq_iov[0].iov_base + 4;
iov[0].iov_len = rqst->rq_iov[0].iov_len - 4;
buflen += iov[0].iov_len;
if (rqst->rq_iov[0].iov_len != 4) {
log_write(ERR, "expected the pdu length in 1st iov, but got %zu\n", rqst->rq_iov[0].iov_len);
return -EINVAL;
}
iov = &rqst->rq_iov[1];
/* total up iov array first */
for (i = 1; i < rqst->rq_nvec; i++) {
iov[i].iov_base = rqst->rq_iov[i].iov_base;
iov[i].iov_len = rqst->rq_iov[i].iov_len;
for (i = 0; i < rqst->rq_nvec-1; i++) {
buflen += iov[i].iov_len;
}
@ -2198,14 +2186,14 @@ int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
goto done;
}
i++;
if (i == rqst->rq_nvec)
if (i == rqst->rq_nvec-1)
break;
}
start = i;
buflen = 0;
} else {
i++;
if (i == rqst->rq_nvec) {
if (i == rqst->rq_nvec-1) {
/* send out all remaining vecs */
remaining_data_length -= buflen;
log_write(INFO,