staging: unisys: Remove num_visornic_open array

As pointed out in a recent review, the num_visornic_open array didn't do
anything useful, and it exposed a potential race in the visornic code that
could arise while taking down a net interface while reading from the
debugfs files. Fix that by removing the array entirely, and just iterating
over all the registered netdevs in a given namespace, filtering on them
having visornic ops (to identify which are ours), and having their queues
not be stopped (identifying that they are up). This should prevent any oops
conditions happening due to changing state in that array, and save us a
bunch of code too.

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/unisys/visornic/visornic_main.c b/drivers/staging/unisys/visornic/visornic_main.c
index c28a347..5bb6cf4 100644 (file)
--- a/drivers/staging/unisys/visornic/visornic_main.c
+++ b/drivers/staging/unisys/visornic/visornic_main.c
@@ -196,8 +196,6 @@ struct visornic_devdata {
        struct chanstat chstat;
 };
 
-/* array of open devices maintained by open() and close() */
-static struct net_device *num_visornic_open[VISORNICSOPENMAX];
 
 /* List of all visornic_devdata structs,
  * linked via the list_all member
@@ -325,178 +323,15 @@ static void visor_thread_stop(struct visor_thread_info *thrinfo)
                thrinfo->id = 0;
 }
 
-/* DebugFS code */
-static ssize_t info_debugfs_read(struct file *file, char __user *buf,
-                                size_t len, loff_t *offset)
-{
-       int i;
-       ssize_t bytes_read = 0;
-       int str_pos = 0;
-       struct visornic_devdata *devdata;
-       char *vbuf;
-
-       if (len > MAX_BUF)
-               len = MAX_BUF;
-       vbuf = kzalloc(len, GFP_KERNEL);
-       if (!vbuf)
-               return -ENOMEM;
-
-       /* for each vnic channel
-        * dump out channel specific data
-        */
-       for (i = 0; i < VISORNICSOPENMAX; i++) {
-               if (!num_visornic_open[i])
-                       continue;
-
-               devdata = netdev_priv(num_visornic_open[i]);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    "Vnic i = %d\n", i);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    "netdev = %s (0x%p), MAC Addr %pM\n",
-                                    num_visornic_open[i]->name,
-                                    num_visornic_open[i],
-                                    num_visornic_open[i]->dev_addr);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    "VisorNic Dev Info = 0x%p\n", devdata);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " num_rcv_bufs = %d\n",
-                                    devdata->num_rcv_bufs);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " max_oustanding_next_xmits = %d\n",
-                                   devdata->max_outstanding_net_xmits);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " upper_threshold_net_xmits = %d\n",
-                                    devdata->upper_threshold_net_xmits);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " lower_threshold_net_xmits = %d\n",
-                                    devdata->lower_threshold_net_xmits);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " queuefullmsg_logged = %d\n",
-                                    devdata->queuefullmsg_logged);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.got_rcv = %lu\n",
-                                    devdata->chstat.got_rcv);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.got_enbdisack = %lu\n",
-                                    devdata->chstat.got_enbdisack);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.got_xmit_done = %lu\n",
-                                    devdata->chstat.got_xmit_done);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.xmit_fail = %lu\n",
-                                    devdata->chstat.xmit_fail);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.sent_enbdis = %lu\n",
-                                    devdata->chstat.sent_enbdis);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.sent_promisc = %lu\n",
-                                    devdata->chstat.sent_promisc);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.sent_post = %lu\n",
-                                    devdata->chstat.sent_post);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.sent_xmit = %lu\n",
-                                    devdata->chstat.sent_xmit);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.reject_count = %lu\n",
-                                    devdata->chstat.reject_count);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " chstat.extra_rcvbufs_sent = %lu\n",
-                                    devdata->chstat.extra_rcvbufs_sent);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_rcv0 = %lu\n", devdata->n_rcv0);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_rcv1 = %lu\n", devdata->n_rcv1);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_rcv2 = %lu\n", devdata->n_rcv2);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_rcvx = %lu\n", devdata->n_rcvx);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " num_rcvbuf_in_iovm = %d\n",
-                                    atomic_read(&devdata->num_rcvbuf_in_iovm));
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " alloc_failed_in_if_needed_cnt = %lu\n",
-                                    devdata->alloc_failed_in_if_needed_cnt);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " alloc_failed_in_repost_rtn_cnt = %lu\n",
-                                    devdata->alloc_failed_in_repost_rtn_cnt);
-               /* str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                *                   " inner_loop_limit_reached_cnt = %lu\n",
-                *                   devdata->inner_loop_limit_reached_cnt);
-                */
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " found_repost_rcvbuf_cnt = %lu\n",
-                                    devdata->found_repost_rcvbuf_cnt);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " repost_found_skb_cnt = %lu\n",
-                                    devdata->repost_found_skb_cnt);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_repost_deficit = %lu\n",
-                                    devdata->n_repost_deficit);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " bad_rcv_buf = %lu\n",
-                                    devdata->bad_rcv_buf);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " n_rcv_packets_not_accepted = %lu\n",
-                                    devdata->n_rcv_packets_not_accepted);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " interrupts_rcvd = %llu\n",
-                                    devdata->interrupts_rcvd);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " interrupts_notme = %llu\n",
-                                    devdata->interrupts_notme);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " interrupts_disabled = %llu\n",
-                                    devdata->interrupts_disabled);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " busy_cnt = %llu\n",
-                                    devdata->busy_cnt);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " flow_control_upper_hits = %llu\n",
-                                    devdata->flow_control_upper_hits);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " flow_control_lower_hits = %llu\n",
-                                    devdata->flow_control_lower_hits);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " thread_wait_ms = %d\n",
-                                    devdata->thread_wait_ms);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                                    " netif_queue = %s\n",
-                                    netif_queue_stopped(devdata->netdev) ?
-                                    "stopped" : "running");
-       }
-       bytes_read = simple_read_from_buffer(buf, len, offset, vbuf, str_pos);
-       kfree(vbuf);
-       return bytes_read;
-}
-
 static ssize_t enable_ints_write(struct file *file,
                                 const char __user *buffer,
                                 size_t count, loff_t *ppos)
 {
-       char buf[4];
-       int i, new_value;
-       struct visornic_devdata *devdata;
-
-       if (count >= ARRAY_SIZE(buf))
-               return -EINVAL;
-
-       buf[count] = '\0';
-       if (copy_from_user(buf, buffer, count))
-               return -EFAULT;
-
-       i = kstrtoint(buf, 10, &new_value);
-       if (i != 0)
-               return -EFAULT;
-
-       /* set all counts to new_value usually 0 */
-       for (i = 0; i < VISORNICSOPENMAX; i++) {
-               if (num_visornic_open[i]) {
-                       devdata = netdev_priv(num_visornic_open[i]);
-                       /* TODO update features bit in channel */
-               }
-       }
-
+       /*
+        * Don't want to break ABI here by having a debugfs
+        * file that no longer exists or is writable, so
+        * lets just make this a vestigual function
+        */
        return count;
 }
 
@@ -760,13 +595,6 @@ visornic_disable_with_timeout(struct net_device *netdev, const int timeout)
                }
        }
 
-       /* remove references from array */
-       for (i = 0; i < VISORNICSOPENMAX; i++)
-               if (num_visornic_open[i] == netdev) {
-                       num_visornic_open[i] = NULL;
-                       break;
-               }
-
        return 0;
 }
 
@@ -882,16 +710,6 @@ visornic_enable_with_timeout(struct net_device *netdev, const int timeout)
                return -EIO;
        }
 
-       /* find an open slot in the array to save off VisorNic references
-        * for debug
-        */
-       for (i = 0; i < VISORNICSOPENMAX; i++) {
-               if (!num_visornic_open[i]) {
-                       num_visornic_open[i] = netdev;
-                       break;
-               }
-       }
-
        return 0;
 }
 
@@ -1642,6 +1460,155 @@ static const struct net_device_ops visornic_dev_ops = {
        .ndo_set_rx_mode = visornic_set_multi,
 };
 
+/* DebugFS code */
+static ssize_t info_debugfs_read(struct file *file, char __user *buf,
+                                size_t len, loff_t *offset)
+{
+       ssize_t bytes_read = 0;
+       int str_pos = 0;
+       struct visornic_devdata *devdata;
+       struct net_device *dev;
+       char *vbuf;
+
+       if (len > MAX_BUF)
+               len = MAX_BUF;
+       vbuf = kzalloc(len, GFP_KERNEL);
+       if (!vbuf)
+               return -ENOMEM;
+
+       /* for each vnic channel
+        * dump out channel specific data
+        */
+       rcu_read_lock();
+       for_each_netdev_rcu(current->nsproxy->net_ns, dev) {
+               /*
+                * Only consider netdevs that are visornic, and are open
+                */
+               if ((dev->netdev_ops != &visornic_dev_ops) ||
+                   (!netif_queue_stopped(dev)))
+                       continue;
+
+               devdata = netdev_priv(dev);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    "netdev = %s (0x%p), MAC Addr %pM\n",
+                                    dev->name,
+                                    dev,
+                                    dev->dev_addr);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    "VisorNic Dev Info = 0x%p\n", devdata);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " num_rcv_bufs = %d\n",
+                                    devdata->num_rcv_bufs);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " max_oustanding_next_xmits = %d\n",
+                                   devdata->max_outstanding_net_xmits);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " upper_threshold_net_xmits = %d\n",
+                                    devdata->upper_threshold_net_xmits);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " lower_threshold_net_xmits = %d\n",
+                                    devdata->lower_threshold_net_xmits);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " queuefullmsg_logged = %d\n",
+                                    devdata->queuefullmsg_logged);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.got_rcv = %lu\n",
+                                    devdata->chstat.got_rcv);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.got_enbdisack = %lu\n",
+                                    devdata->chstat.got_enbdisack);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.got_xmit_done = %lu\n",
+                                    devdata->chstat.got_xmit_done);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.xmit_fail = %lu\n",
+                                    devdata->chstat.xmit_fail);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.sent_enbdis = %lu\n",
+                                    devdata->chstat.sent_enbdis);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.sent_promisc = %lu\n",
+                                    devdata->chstat.sent_promisc);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.sent_post = %lu\n",
+                                    devdata->chstat.sent_post);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.sent_xmit = %lu\n",
+                                    devdata->chstat.sent_xmit);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.reject_count = %lu\n",
+                                    devdata->chstat.reject_count);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " chstat.extra_rcvbufs_sent = %lu\n",
+                                    devdata->chstat.extra_rcvbufs_sent);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_rcv0 = %lu\n", devdata->n_rcv0);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_rcv1 = %lu\n", devdata->n_rcv1);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_rcv2 = %lu\n", devdata->n_rcv2);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_rcvx = %lu\n", devdata->n_rcvx);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " num_rcvbuf_in_iovm = %d\n",
+                                    atomic_read(&devdata->num_rcvbuf_in_iovm));
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " alloc_failed_in_if_needed_cnt = %lu\n",
+                                    devdata->alloc_failed_in_if_needed_cnt);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " alloc_failed_in_repost_rtn_cnt = %lu\n",
+                                    devdata->alloc_failed_in_repost_rtn_cnt);
+               /* str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                *                   " inner_loop_limit_reached_cnt = %lu\n",
+                *                   devdata->inner_loop_limit_reached_cnt);
+                */
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " found_repost_rcvbuf_cnt = %lu\n",
+                                    devdata->found_repost_rcvbuf_cnt);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " repost_found_skb_cnt = %lu\n",
+                                    devdata->repost_found_skb_cnt);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_repost_deficit = %lu\n",
+                                    devdata->n_repost_deficit);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " bad_rcv_buf = %lu\n",
+                                    devdata->bad_rcv_buf);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " n_rcv_packets_not_accepted = %lu\n",
+                                    devdata->n_rcv_packets_not_accepted);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " interrupts_rcvd = %llu\n",
+                                    devdata->interrupts_rcvd);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " interrupts_notme = %llu\n",
+                                    devdata->interrupts_notme);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " interrupts_disabled = %llu\n",
+                                    devdata->interrupts_disabled);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " busy_cnt = %llu\n",
+                                    devdata->busy_cnt);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " flow_control_upper_hits = %llu\n",
+                                    devdata->flow_control_upper_hits);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " flow_control_lower_hits = %llu\n",
+                                    devdata->flow_control_lower_hits);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " thread_wait_ms = %d\n",
+                                    devdata->thread_wait_ms);
+               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
+                                    " netif_queue = %s\n",
+                                    netif_queue_stopped(devdata->netdev) ?
+                                    "stopped" : "running");
+       }
+       rcu_read_unlock();
+       bytes_read = simple_read_from_buffer(buf, len, offset, vbuf, str_pos);
+       kfree(vbuf);
+       return bytes_read;
+}
+
 /**
  *     send_rcv_posts_if_needed
  *     @devdata: visornic device