lkml.org 
[lkml]   [2018]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.16 036/113] cifs: smbd: Avoid allocating iov on the stack
    Date
    4.16-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Long Li <longli@microsoft.com>

    commit 8bcda1d2a79da4ab84162574eee2c9f6e1a12a03 upstream.

    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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/cifs/smbdirect.c | 36 ++++++++++++------------------------
    1 file changed, 12 insertions(+), 24 deletions(-)

    --- a/fs/cifs/smbdirect.c
    +++ b/fs/cifs/smbdirect.c
    @@ -2086,7 +2086,7 @@ int smbd_send(struct smbd_connection *in
    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 *in
    }

    /*
    - * 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;
    }

    @@ -2194,14 +2182,14 @@ int smbd_send(struct smbd_connection *in
    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,

    \
     
     \ /
      Last update: 2018-04-30 21:47    [W:4.023 / U:0.168 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site