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Commit 8bcda1d2 authored by Long Li's avatar Long Li Committed by Steve French
Browse files

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: default avatarLong Li <longli@microsoft.com>
Acked-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent bb4c0419

fs/cifs/smbdirect.c

+12 −24
Original line number Diff line number Diff line
@@ -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,