Handle variable number of SGEs in client smbdirect send.

If/when an outgoing request contains more scatter/gather segments
than can be mapped in a single RDMA send work request, use smbdirect
fragments to send it in multiple packets.

Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 4908ca5..6ac424d 100644 (file)
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -1984,10 +1984,11 @@ int smbd_send(struct TCP_Server_Info *server,
        int num_rqst, struct smb_rqst *rqst_array)
 {
        struct smbd_connection *info = server->smbd_conn;
-       struct kvec vec;
+       struct kvec vecs[SMBDIRECT_MAX_SEND_SGE - 1];
        int nvecs;
        int size;
        unsigned int buflen, remaining_data_length;
+       unsigned int offset, remaining_vec_data_length;
        int start, i, j;
        int max_iov_size =
                info->max_send_size - sizeof(struct smbd_data_transfer);
@@ -1996,10 +1997,8 @@ int smbd_send(struct TCP_Server_Info *server,
        struct smb_rqst *rqst;
        int rqst_idx;
 
-       if (info->transport_status != SMBD_CONNECTED) {
-               rc = -EAGAIN;
-               goto done;
-       }
+       if (info->transport_status != SMBD_CONNECTED)
+               return -EAGAIN;
 
        /*
         * Add in the page array if there is one. The caller needs to set
@@ -2010,125 +2009,95 @@ int smbd_send(struct TCP_Server_Info *server,
        for (i = 0; i < num_rqst; i++)
                remaining_data_length += smb_rqst_len(server, &rqst_array[i]);
 
-       if (remaining_data_length > info->max_fragmented_send_size) {
+       if (unlikely(remaining_data_length > info->max_fragmented_send_size)) {
+               /* assertion: payload never exceeds negotiated maximum */
                log_write(ERR, "payload size %d > max size %d\n",
                        remaining_data_length, info->max_fragmented_send_size);
-               rc = -EINVAL;
-               goto done;
+               return -EINVAL;
        }
 
        log_write(INFO, "num_rqst=%d total length=%u\n",
                        num_rqst, remaining_data_length);
 
        rqst_idx = 0;
-next_rqst:
-       rqst = &rqst_array[rqst_idx];
-       iov = rqst->rq_iov;
-
-       cifs_dbg(FYI, "Sending smb (RDMA): idx=%d smb_len=%lu\n",
-               rqst_idx, smb_rqst_len(server, rqst));
-       for (i = 0; i < rqst->rq_nvec; i++)
-               dump_smb(iov[i].iov_base, iov[i].iov_len);
-
-
-       log_write(INFO, "rqst_idx=%d nvec=%d rqst->rq_npages=%d rq_pagesz=%d rq_tailsz=%d buflen=%lu\n",
-                 rqst_idx, rqst->rq_nvec, rqst->rq_npages, rqst->rq_pagesz,
-                 rqst->rq_tailsz, smb_rqst_len(server, rqst));
-
-       start = i = 0;
-       buflen = 0;
-       while (true) {
-               buflen += iov[i].iov_len;
-               if (buflen > max_iov_size) {
-                       if (i > start) {
-                               remaining_data_length -=
-                                       (buflen-iov[i].iov_len);
-                               log_write(INFO, "sending iov[] from start=%d i=%d nvecs=%d remaining_data_length=%d\n",
-                                         start, i, i - start,
-                                         remaining_data_length);
-                               rc = smbd_post_send_data(
-                                       info, &iov[start], i-start,
-                                       remaining_data_length);
-                               if (rc)
-                                       goto done;
-                       } else {
-                               /* iov[start] is too big, break it */
-                               nvecs = (buflen+max_iov_size-1)/max_iov_size;
-                               log_write(INFO, "iov[%d] iov_base=%p buflen=%d break to %d vectors\n",
-                                         start, iov[start].iov_base,
-                                         buflen, nvecs);
-                               for (j = 0; j < nvecs; j++) {
-                                       vec.iov_base =
-                                               (char *)iov[start].iov_base +
-                                               j*max_iov_size;
-                                       vec.iov_len = max_iov_size;
-                                       if (j == nvecs-1)
-                                               vec.iov_len =
-                                                       buflen -
-                                                       max_iov_size*(nvecs-1);
-                                       remaining_data_length -= vec.iov_len;
-                                       log_write(INFO,
-                                               "sending vec j=%d iov_base=%p iov_len=%zu remaining_data_length=%d\n",
-                                                 j, vec.iov_base, vec.iov_len,
-                                                 remaining_data_length);
-                                       rc = smbd_post_send_data(
-                                               info, &vec, 1,
-                                               remaining_data_length);
-                                       if (rc)
-                                               goto done;
+       do {
+               rqst = &rqst_array[rqst_idx];
+               iov = rqst->rq_iov;
+
+               cifs_dbg(FYI, "Sending smb (RDMA): idx=%d smb_len=%lu\n",
+                       rqst_idx, smb_rqst_len(server, rqst));
+               remaining_vec_data_length = 0;
+               for (i = 0; i < rqst->rq_nvec; i++) {
+                       remaining_vec_data_length += iov[i].iov_len;
+                       dump_smb(iov[i].iov_base, iov[i].iov_len);
+               }
+
+               log_write(INFO, "rqst_idx=%d nvec=%d rqst->rq_npages=%d rq_pagesz=%d rq_tailsz=%d buflen=%lu\n",
+                         rqst_idx, rqst->rq_nvec,
+                         rqst->rq_npages, rqst->rq_pagesz,
+                         rqst->rq_tailsz, smb_rqst_len(server, rqst));
+
+               start = 0;
+               offset = 0;
+               do {
+                       buflen = 0;
+                       i = start;
+                       j = 0;
+                       while (i < rqst->rq_nvec &&
+                               j < SMBDIRECT_MAX_SEND_SGE - 1 &&
+                               buflen < max_iov_size) {
+
+                               vecs[j].iov_base = iov[i].iov_base + offset;
+                               if (buflen + iov[i].iov_len > max_iov_size) {
+                                       vecs[j].iov_len =
+                                               max_iov_size - iov[i].iov_len;
+                                       buflen = max_iov_size;
+                                       offset = vecs[j].iov_len;
+                               } else {
+                                       vecs[j].iov_len =
+                                               iov[i].iov_len - offset;
+                                       buflen += vecs[j].iov_len;
+                                       offset = 0;
+                                       ++i;
                                }
-                               i++;
-                               if (i == rqst->rq_nvec)
-                                       break;
+                               ++j;
                        }
+
+                       remaining_vec_data_length -= buflen;
+                       remaining_data_length -= buflen;
+                       log_write(INFO, "sending %s iov[%d] from start=%d nvecs=%d remaining_data_length=%d\n",
+                                       remaining_vec_data_length > 0 ?
+                                               "partial" : "complete",
+                                       rqst->rq_nvec, start, j,
+                                       remaining_data_length);
+
                        start = i;
-                       buflen = 0;
-               } else {
-                       i++;
-                       if (i == rqst->rq_nvec) {
-                               /* send out all remaining vecs */
-                               remaining_data_length -= buflen;
-                               log_write(INFO, "sending iov[] from start=%d i=%d nvecs=%d remaining_data_length=%d\n",
-                                         start, i, i - start,
+                       rc = smbd_post_send_data(info, vecs, j, remaining_data_length);
+                       if (rc)
+                               goto done;
+               } while (remaining_vec_data_length > 0);
+
+               /* now sending pages if there are any */
+               for (i = 0; i < rqst->rq_npages; i++) {
+                       rqst_page_get_length(rqst, i, &buflen, &offset);
+                       nvecs = (buflen + max_iov_size - 1) / max_iov_size;
+                       log_write(INFO, "sending pages buflen=%d nvecs=%d\n",
+                               buflen, nvecs);
+                       for (j = 0; j < nvecs; j++) {
+                               size = min_t(unsigned int, max_iov_size, remaining_data_length);
+                               remaining_data_length -= size;
+                               log_write(INFO, "sending pages i=%d offset=%d size=%d remaining_data_length=%d\n",
+                                         i, j * max_iov_size + offset, size,
                                          remaining_data_length);
-                               rc = smbd_post_send_data(info, &iov[start],
-                                       i-start, remaining_data_length);
+                               rc = smbd_post_send_page(
+                                       info, rqst->rq_pages[i],
+                                       j*max_iov_size + offset,
+                                       size, remaining_data_length);
                                if (rc)
                                        goto done;
-                               break;
                        }
                }
-               log_write(INFO, "looping i=%d buflen=%d\n", i, buflen);
-       }
-
-       /* now sending pages if there are any */
-       for (i = 0; i < rqst->rq_npages; i++) {
-               unsigned int offset;
-
-               rqst_page_get_length(rqst, i, &buflen, &offset);
-               nvecs = (buflen + max_iov_size - 1) / max_iov_size;
-               log_write(INFO, "sending pages buflen=%d nvecs=%d\n",
-                       buflen, nvecs);
-               for (j = 0; j < nvecs; j++) {
-                       size = max_iov_size;
-                       if (j == nvecs-1)
-                               size = buflen - j*max_iov_size;
-                       remaining_data_length -= size;
-                       log_write(INFO, "sending pages i=%d offset=%d size=%d remaining_data_length=%d\n",
-                                 i, j * max_iov_size + offset, size,
-                                 remaining_data_length);
-                       rc = smbd_post_send_page(
-                               info, rqst->rq_pages[i],
-                               j*max_iov_size + offset,
-                               size, remaining_data_length);
-                       if (rc)
-                               goto done;
-               }
-       }
-
-       rqst_idx++;
-       if (rqst_idx < num_rqst)
-               goto next_rqst;
+       } while (++rqst_idx < num_rqst);
 
 done:
        /*