NTB: Remove reads across NTB
[cascardo/linux.git] / drivers / ntb / ntb_transport.c
index 1bed1ba..69c58da 100644 (file)
@@ -78,6 +78,10 @@ struct ntb_queue_entry {
        unsigned int flags;
 };
 
+struct ntb_rx_info {
+       unsigned int entry;
+};
+
 struct ntb_transport_qp {
        struct ntb_transport *transport;
        struct ntb_device *ndev;
@@ -87,13 +91,16 @@ struct ntb_transport_qp {
        bool qp_link;
        u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 
+       struct ntb_rx_info *rx_info;
+       struct ntb_rx_info *remote_rx_info;
+
        void (*tx_handler) (struct ntb_transport_qp *qp, void *qp_data,
                            void *data, int len);
        struct list_head tx_free_q;
        spinlock_t ntb_tx_free_q_lock;
-       void *tx_mw_begin;
-       void *tx_mw_end;
-       void *tx_offset;
+       void *tx_mw;
+       unsigned int tx_index;
+       unsigned int tx_max_entry;
        unsigned int tx_max_frame;
 
        void (*rx_handler) (struct ntb_transport_qp *qp, void *qp_data,
@@ -103,9 +110,9 @@ struct ntb_transport_qp {
        struct list_head rx_free_q;
        spinlock_t ntb_rx_pend_q_lock;
        spinlock_t ntb_rx_free_q_lock;
-       void *rx_buff_begin;
-       void *rx_buff_end;
-       void *rx_offset;
+       void *rx_buff;
+       unsigned int rx_index;
+       unsigned int rx_max_entry;
        unsigned int rx_max_frame;
 
        void (*event_handler) (void *data, int status);
@@ -394,11 +401,11 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "rx_err_ver - \t%llu\n", qp->rx_err_ver);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "rx_buff_begin - %p\n", qp->rx_buff_begin);
+                              "rx_buff - \t%p\n", qp->rx_buff);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "rx_offset - \t%p\n", qp->rx_offset);
+                              "rx_index - \t%u\n", qp->rx_index);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "rx_buff_end - \t%p\n", qp->rx_buff_end);
+                              "rx_max_entry - \t%u\n", qp->rx_max_entry);
 
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "tx_bytes - \t%llu\n", qp->tx_bytes);
@@ -407,11 +414,11 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "tx_ring_full - \t%llu\n", qp->tx_ring_full);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "tx_mw_begin - \t%p\n", qp->tx_mw_begin);
+                              "tx_mw - \t%p\n", qp->tx_mw);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "tx_offset - \t%p\n", qp->tx_offset);
+                              "tx_index - \t%u\n", qp->tx_index);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "tx_mw_end - \t%p\n", qp->tx_mw_end);
+                              "tx_max_entry - \t%u\n", qp->tx_max_entry);
 
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "\nQP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
@@ -465,7 +472,7 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
        struct ntb_transport_qp *qp = &nt->qps[qp_num];
        unsigned int rx_size, num_qps_mw;
        u8 mw_num = QP_TO_MW(qp_num);
-       void *offset;
+       unsigned int i;
 
        WARN_ON(nt->mw[mw_num].virt_addr == 0);
 
@@ -474,18 +481,24 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
        else
                num_qps_mw = nt->max_qps / NTB_NUM_MW;
 
-       rx_size = nt->mw[mw_num].size / num_qps_mw;
-       qp->rx_buff_begin = nt->mw[mw_num].virt_addr +
-                           (qp_num / NTB_NUM_MW * rx_size);
-       qp->rx_buff_end = qp->rx_buff_begin + rx_size;
-       qp->rx_offset = qp->rx_buff_begin;
+       rx_size = (unsigned int) nt->mw[mw_num].size / num_qps_mw;
+       qp->remote_rx_info = nt->mw[mw_num].virt_addr +
+                            (qp_num / NTB_NUM_MW * rx_size);
+       rx_size -= sizeof(struct ntb_rx_info);
+
+       qp->rx_buff = qp->remote_rx_info + sizeof(struct ntb_rx_info);
        qp->rx_max_frame = min(transport_mtu, rx_size);
+       qp->rx_max_entry = rx_size / qp->rx_max_frame;
+       qp->rx_index = 0;
+
+       qp->remote_rx_info->entry = qp->rx_max_entry;
 
        /* setup the hdr offsets with 0's */
-       for (offset = qp->rx_buff_begin + qp->rx_max_frame -
-                     sizeof(struct ntb_payload_header);
-            offset < qp->rx_buff_end; offset += qp->rx_max_frame)
+       for (i = 0; i < qp->rx_max_entry; i++) {
+               void *offset = qp->rx_buff + qp->rx_max_frame * (i + 1) -
+                              sizeof(struct ntb_payload_header);
                memset(offset, 0, sizeof(struct ntb_payload_header));
+       }
 
        qp->rx_pkts = 0;
        qp->tx_pkts = 0;
@@ -762,12 +775,15 @@ static void ntb_transport_init_queue(struct ntb_transport *nt,
        else
                num_qps_mw = nt->max_qps / NTB_NUM_MW;
 
-       tx_size = ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw;
-       qp->tx_mw_begin = ntb_get_mw_vbase(nt->ndev, mw_num) +
-                         (qp_num / NTB_NUM_MW * tx_size);
-       qp->tx_mw_end = qp->tx_mw_begin + tx_size;
-       qp->tx_offset = qp->tx_mw_begin;
+       tx_size = (unsigned int) ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw;
+       qp->rx_info = ntb_get_mw_vbase(nt->ndev, mw_num) +
+                     (qp_num / NTB_NUM_MW * tx_size);
+       tx_size -= sizeof(struct ntb_rx_info);
+
+       qp->tx_mw = qp->rx_info + sizeof(struct ntb_rx_info);
        qp->tx_max_frame = min(transport_mtu, tx_size);
+       qp->tx_max_entry = tx_size / qp->tx_max_frame;
+       qp->tx_index = 0;
 
        if (nt->debugfs_dir) {
                char debugfs_name[4];
@@ -894,21 +910,8 @@ void ntb_transport_free(void *transport)
 static void ntb_rx_copy_task(struct ntb_transport_qp *qp,
                             struct ntb_queue_entry *entry, void *offset)
 {
-
-       struct ntb_payload_header *hdr;
-
-       BUG_ON(offset < qp->rx_buff_begin ||
-              offset + qp->rx_max_frame >= qp->rx_buff_end);
-
-       hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
-       entry->len = hdr->len;
-
        memcpy(entry->buf, offset, entry->len);
 
-       /* Ensure that the data is fully copied out before clearing the flag */
-       wmb();
-       hdr->flags = 0;
-
        if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
                qp->rx_handler(qp, qp->cb_data, entry->cb_data, entry->len);
 
@@ -921,10 +924,11 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
        struct ntb_queue_entry *entry;
        void *offset;
 
+       offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
+       hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
+
        entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
        if (!entry) {
-               hdr = offset + qp->rx_max_frame -
-                     sizeof(struct ntb_payload_header);
                dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
                        "no buffer - HDR ver %llu, len %d, flags %x\n",
                        hdr->ver, hdr->len, hdr->flags);
@@ -932,9 +936,6 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
                return -ENOMEM;
        }
 
-       offset = qp->rx_offset;
-       hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
-
        if (!(hdr->flags & DESC_DONE_FLAG)) {
                ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
                             &qp->rx_pend_q);
@@ -957,30 +958,20 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
 
                ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
                             &qp->rx_pend_q);
-
-               /* Ensure that the data is fully copied out before clearing the
-                * done flag
-                */
-               wmb();
-               hdr->flags = 0;
                goto out;
        }
 
        dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
-               "rx offset %p, ver %llu - %d payload received, buf size %d\n",
-               qp->rx_offset, hdr->ver, hdr->len, entry->len);
+               "rx offset %u, ver %llu - %d payload received, buf size %d\n",
+               qp->rx_index, hdr->ver, hdr->len, entry->len);
 
-       if (hdr->len <= entry->len)
+       if (hdr->len <= entry->len) {
+               entry->len = hdr->len;
                ntb_rx_copy_task(qp, entry, offset);
-       else {
+       else {
                ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
                             &qp->rx_pend_q);
 
-               /* Ensure that the data is fully copied out before clearing the
-                * done flag
-                */
-               wmb();
-               hdr->flags = 0;
                qp->rx_err_oflow++;
                dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
                        "RX overflow! Wanted %d got %d\n",
@@ -991,9 +982,13 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
        qp->rx_pkts++;
 
 out:
-       qp->rx_offset += qp->rx_max_frame;
-       if (qp->rx_offset + qp->rx_max_frame >= qp->rx_buff_end)
-               qp->rx_offset = qp->rx_buff_begin;
+       /* Ensure that the data is fully copied out before clearing the flag */
+       wmb();
+       hdr->flags = 0;
+       qp->rx_info->entry = qp->rx_index;
+
+       qp->rx_index++;
+       qp->rx_index %= qp->rx_max_entry;
 
        return 0;
 }
@@ -1024,9 +1019,6 @@ static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
 {
        struct ntb_payload_header *hdr;
 
-       BUG_ON(offset < qp->tx_mw_begin ||
-              offset + qp->tx_max_frame >= qp->tx_mw_end);
-
        memcpy_toio(offset, entry->buf, entry->len);
 
        hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
@@ -1057,16 +1049,14 @@ static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
 static int ntb_process_tx(struct ntb_transport_qp *qp,
                          struct ntb_queue_entry *entry)
 {
-       struct ntb_payload_header *hdr;
        void *offset;
 
-       offset = qp->tx_offset;
-       hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
+       offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
 
-       dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %p, entry len %d flags %x buff %p\n",
-               qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags,
+       dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %u, entry len %d flags %x buff %p\n",
+               qp->tx_pkts, offset, qp->tx_index, entry->len, entry->flags,
                entry->buf);
-       if (hdr->flags) {
+       if (qp->tx_index == qp->remote_rx_info->entry) {
                qp->tx_ring_full++;
                return -EAGAIN;
        }
@@ -1082,9 +1072,8 @@ static int ntb_process_tx(struct ntb_transport_qp *qp,
 
        ntb_tx_copy_task(qp, entry, offset);
 
-       qp->tx_offset += qp->tx_max_frame;
-       if (qp->tx_offset + qp->tx_max_frame >= qp->tx_mw_end)
-               qp->tx_offset = qp->tx_mw_begin;
+       qp->tx_index++;
+       qp->tx_index %= qp->tx_max_entry;
 
        qp->tx_pkts++;