CIFS: SMBD: Implement function to send data via RDMA send
authorLong Li <longli@microsoft.com>
Thu, 23 Nov 2017 00:38:42 +0000 (17:38 -0700)
committerSteve French <smfrench@gmail.com>
Thu, 25 Jan 2018 01:49:06 +0000 (19:49 -0600)
The transport doesn't maintain send buffers or send queue for transferring
payload via RDMA send. There is no data copy in the transport on send.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
fs/cifs/smbdirect.c
fs/cifs/smbdirect.h

index d8c5fea3707c3238940e00674663fbeafc0850b9..3351873db93fde0c7230013e984bd948825fa3ea 100644 (file)
@@ -41,6 +41,12 @@ static int smbd_post_recv(
                struct smbd_response *response);
 
 static int smbd_post_send_empty(struct smbd_connection *info);
+static int smbd_post_send_data(
+               struct smbd_connection *info,
+               struct kvec *iov, int n_vec, int remaining_data_length);
+static int smbd_post_send_page(struct smbd_connection *info,
+               struct page *page, unsigned long offset,
+               size_t size, int remaining_data_length);
 
 /* SMBD version number */
 #define SMBD_V1        0x0100
@@ -177,6 +183,10 @@ static void smbd_destroy_rdma_work(struct work_struct *work)
        log_rdma_event(INFO, "cancelling send immediate work\n");
        cancel_delayed_work_sync(&info->send_immediate_work);
 
+       log_rdma_event(INFO, "wait for all send to finish\n");
+       wait_event(info->wait_smbd_send_pending,
+               info->smbd_send_pending == 0);
+
        log_rdma_event(INFO, "wait for all recv to finish\n");
        wake_up_interruptible(&info->wait_reassembly_queue);
        wait_event(info->wait_smbd_recv_pending,
@@ -1077,6 +1087,24 @@ dma_mapping_failure:
        return rc;
 }
 
+/*
+ * Send a page
+ * page: the page to send
+ * offset: offset in the page to send
+ * size: length in the page to send
+ * remaining_data_length: remaining data to send in this payload
+ */
+static int smbd_post_send_page(struct smbd_connection *info, struct page *page,
+               unsigned long offset, size_t size, int remaining_data_length)
+{
+       struct scatterlist sgl;
+
+       sg_init_table(&sgl, 1);
+       sg_set_page(&sgl, page, size, offset);
+
+       return smbd_post_send_sgl(info, &sgl, size, remaining_data_length);
+}
+
 /*
  * Send an empty message
  * Empty message is used to extend credits to peer to for keep live
@@ -1088,6 +1116,35 @@ static int smbd_post_send_empty(struct smbd_connection *info)
        return smbd_post_send_sgl(info, NULL, 0, 0);
 }
 
+/*
+ * Send a data buffer
+ * iov: the iov array describing the data buffers
+ * n_vec: number of iov array
+ * remaining_data_length: remaining data to send following this packet
+ * in segmented SMBD packet
+ */
+static int smbd_post_send_data(
+       struct smbd_connection *info, struct kvec *iov, int n_vec,
+       int remaining_data_length)
+{
+       int i;
+       u32 data_length = 0;
+       struct scatterlist sgl[SMBDIRECT_MAX_SGE];
+
+       if (n_vec > SMBDIRECT_MAX_SGE) {
+               cifs_dbg(VFS, "Can't fit data to SGL, n_vec=%d\n", n_vec);
+               return -ENOMEM;
+       }
+
+       sg_init_table(sgl, n_vec);
+       for (i = 0; i < n_vec; i++) {
+               data_length += iov[i].iov_len;
+               sg_set_buf(&sgl[i], iov[i].iov_base, iov[i].iov_len);
+       }
+
+       return smbd_post_send_sgl(info, sgl, data_length, remaining_data_length);
+}
+
 /*
  * Post a receive request to the transport
  * The remote peer can only send data when a receive request is posted
@@ -1652,6 +1709,9 @@ struct smbd_connection *_smbd_get_connection(
        queue_delayed_work(info->workqueue, &info->idle_timer_work,
                info->keep_alive_interval*HZ);
 
+       init_waitqueue_head(&info->wait_smbd_send_pending);
+       info->smbd_send_pending = 0;
+
        init_waitqueue_head(&info->wait_smbd_recv_pending);
        info->smbd_recv_pending = 0;
 
@@ -1943,3 +2003,189 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
                msg->msg_iter.count = 0;
        return rc;
 }
+
+/*
+ * Send data to transport
+ * Each rqst is transported as a SMBDirect payload
+ * rqst: the data to write
+ * return value: 0 if successfully write, otherwise error code
+ */
+int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst)
+{
+       struct kvec vec;
+       int nvecs;
+       int size;
+       int buflen = 0, remaining_data_length;
+       int start, i, j;
+       int max_iov_size =
+               info->max_send_size - sizeof(struct smbd_data_transfer);
+       struct kvec iov[SMBDIRECT_MAX_SGE];
+       int rc;
+
+       info->smbd_send_pending++;
+       if (info->transport_status != SMBD_CONNECTED) {
+               rc = -ENODEV;
+               goto done;
+       }
+
+       /*
+        * 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
+        * 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;
+
+       /* 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;
+               buflen += iov[i].iov_len;
+       }
+
+       /* add in the page array if there is one */
+       if (rqst->rq_npages) {
+               buflen += rqst->rq_pagesz * (rqst->rq_npages - 1);
+               buflen += rqst->rq_tailsz;
+       }
+
+       if (buflen + sizeof(struct smbd_data_transfer) >
+               info->max_fragmented_send_size) {
+               log_write(ERR, "payload size %d > max size %d\n",
+                       buflen, info->max_fragmented_send_size);
+               rc = -EINVAL;
+               goto done;
+       }
+
+       remaining_data_length = buflen;
+
+       log_write(INFO, "rqst->rq_nvec=%d rqst->rq_npages=%d rq_pagesz=%d "
+               "rq_tailsz=%d buflen=%d\n",
+               rqst->rq_nvec, rqst->rq_npages, rqst->rq_pagesz,
+               rqst->rq_tailsz, buflen);
+
+       start = i = iov[0].iov_len ? 0 : 1;
+       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;
+                               }
+                               i++;
+                       }
+                       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,
+                                       remaining_data_length);
+                               rc = smbd_post_send_data(info, &iov[start],
+                                       i-start, 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++) {
+               buflen = (i == rqst->rq_npages-1) ?
+                       rqst->rq_tailsz : rqst->rq_pagesz;
+               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, size, remaining_data_length);
+                       rc = smbd_post_send_page(
+                               info, rqst->rq_pages[i], j*max_iov_size,
+                               size, remaining_data_length);
+                       if (rc)
+                               goto done;
+               }
+       }
+
+done:
+       /*
+        * As an optimization, we don't wait for individual I/O to finish
+        * before sending the next one.
+        * Send them all and wait for pending send count to get to 0
+        * that means all the I/Os have been out and we are good to return
+        */
+
+       wait_event(info->wait_send_payload_pending,
+               atomic_read(&info->send_payload_pending) == 0);
+
+       info->smbd_send_pending--;
+       wake_up(&info->wait_smbd_send_pending);
+
+       return rc;
+}
index c072a68e13216a062b66dc311cd6188ff12e7237..27453ef2181f4eb8f57f606cfddef5e1c9a2d23d 100644 (file)
@@ -92,6 +92,9 @@ struct smbd_connection {
 
        /* Activity accoutning */
        /* Pending reqeusts issued from upper layer */
+       int smbd_send_pending;
+       wait_queue_head_t wait_smbd_send_pending;
+
        int smbd_recv_pending;
        wait_queue_head_t wait_smbd_recv_pending;
 
@@ -257,6 +260,7 @@ void smbd_destroy(struct smbd_connection *info);
 
 /* Interface for carrying upper layer I/O through send/recv */
 int smbd_recv(struct smbd_connection *info, struct msghdr *msg);
+int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst);
 
 #else
 #define cifs_rdma_enabled(server)      0
@@ -266,6 +270,7 @@ static inline void *smbd_get_connection(
 static inline int smbd_reconnect(struct TCP_Server_Info *server) {return -1; }
 static inline void smbd_destroy(struct smbd_connection *info) {}
 static inline int smbd_recv(struct smbd_connection *info, struct msghdr *msg) {return -1; }
+static inline int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst) {return -1; }
 #endif
 
 #endif