IB/umad: Add P_Key index support

Add support for setting the P_Key index of sent MADs and getting the
P_Key index of received MADs.  This requires a change to the layout of
the ABI structure struct ib_user_mad_hdr, so to avoid breaking
compatibility, we default to the old (unchanged) ABI and add a new
ioctl IB_USER_MAD_ENABLE_PKEY that allows applications that are aware
of the new ABI to opt into using it.

We plan on switching to the new ABI by default in a year or so, and
this patch adds a warning that is printed when an application uses the
old ABI, to push people towards converting to the new ABI.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Hal Rosenstock <hal@xsigo.com>

1 files changed, 73 insertions, 29 deletions

diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index d97ded25c4ff..aee29139368c 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -118,6 +118,8 @@ struct ib_umad_file {
         wait_queue_head_t       recv_wait;
         struct ib_mad_agent    *agent[IB_UMAD_MAX_AGENTS];
         int                     agents_dead;
+        u8                      use_pkey_index;
+        u8                      already_used;
 };
 
 struct ib_umad_packet {
@@ -147,6 +149,12 @@ static void ib_umad_release_dev(struct kref *ref)
         kfree(dev);
 }
 
+static int hdr_size(struct ib_umad_file *file)
+{
+        return file->use_pkey_index ? sizeof (struct ib_user_mad_hdr) :
+                sizeof (struct ib_user_mad_hdr_old);
+}
+
 /* caller must hold port->mutex at least for reading */
 static struct ib_mad_agent *__get_agent(struct ib_umad_file *file, int id)
 {
@@ -221,13 +229,13 @@ static void recv_handler(struct ib_mad_agent *agent,
         packet->length = mad_recv_wc->mad_len;
         packet->recv_wc = mad_recv_wc;
 
-        packet->mad.hdr.status    = 0;
-        packet->mad.hdr.length    = sizeof (struct ib_user_mad) +
-                                    mad_recv_wc->mad_len;
-        packet->mad.hdr.qpn       = cpu_to_be32(mad_recv_wc->wc->src_qp);
-        packet->mad.hdr.lid       = cpu_to_be16(mad_recv_wc->wc->slid);
-        packet->mad.hdr.sl        = mad_recv_wc->wc->sl;
-        packet->mad.hdr.path_bits = mad_recv_wc->wc->dlid_path_bits;
+        packet->mad.hdr.status     = 0;
+        packet->mad.hdr.length     = hdr_size(file) + mad_recv_wc->mad_len;
+        packet->mad.hdr.qpn        = cpu_to_be32(mad_recv_wc->wc->src_qp);
+        packet->mad.hdr.lid        = cpu_to_be16(mad_recv_wc->wc->slid);
+        packet->mad.hdr.sl         = mad_recv_wc->wc->sl;
+        packet->mad.hdr.path_bits  = mad_recv_wc->wc->dlid_path_bits;
+        packet->mad.hdr.pkey_index = mad_recv_wc->wc->pkey_index;
         packet->mad.hdr.grh_present = !!(mad_recv_wc->wc->wc_flags & IB_WC_GRH);
         if (packet->mad.hdr.grh_present) {
                 struct ib_ah_attr ah_attr;
@@ -253,8 +261,8 @@ err1:
         ib_free_recv_mad(mad_recv_wc);
 }
 
-static ssize_t copy_recv_mad(char __user *buf, struct ib_umad_packet *packet,
-                             size_t count)
+static ssize_t copy_recv_mad(struct ib_umad_file *file, char __user *buf,
+                             struct ib_umad_packet *packet, size_t count)
 {
         struct ib_mad_recv_buf *recv_buf;
         int left, seg_payload, offset, max_seg_payload;
@@ -262,15 +270,15 @@ static ssize_t copy_recv_mad(char __user *buf, struct ib_umad_packet *packet,
         /* We need enough room to copy the first (or only) MAD segment. */
         recv_buf = &packet->recv_wc->recv_buf;
         if ((packet->length <= sizeof (*recv_buf->mad) &&
-             count < sizeof (packet->mad) + packet->length) ||
+             count < hdr_size(file) + packet->length) ||
             (packet->length > sizeof (*recv_buf->mad) &&
-             count < sizeof (packet->mad) + sizeof (*recv_buf->mad)))
+             count < hdr_size(file) + sizeof (*recv_buf->mad)))
                 return -EINVAL;
 
-        if (copy_to_user(buf, &packet->mad, sizeof (packet->mad)))
+        if (copy_to_user(buf, &packet->mad, hdr_size(file)))
                 return -EFAULT;
 
-        buf += sizeof (packet->mad);
+        buf += hdr_size(file);
         seg_payload = min_t(int, packet->length, sizeof (*recv_buf->mad));
         if (copy_to_user(buf, recv_buf->mad, seg_payload))
                 return -EFAULT;
@@ -280,7 +288,7 @@ static ssize_t copy_recv_mad(char __user *buf, struct ib_umad_packet *packet,
                  * Multipacket RMPP MAD message. Copy remainder of message.
                  * Note that last segment may have a shorter payload.
                  */
-                if (count < sizeof (packet->mad) + packet->length) {
+                if (count < hdr_size(file) + packet->length) {
                         /*
                          * The buffer is too small, return the first RMPP segment,
                          * which includes the RMPP message length.
@@ -300,18 +308,23 @@ static ssize_t copy_recv_mad(char __user *buf, struct ib_umad_packet *packet,
                                 return -EFAULT;
                 }
         }
-        return sizeof (packet->mad) + packet->length;
+        return hdr_size(file) + packet->length;
 }
 
-static ssize_t copy_send_mad(char __user *buf, struct ib_umad_packet *packet,
-                             size_t count)
+static ssize_t copy_send_mad(struct ib_umad_file *file, char __user *buf,
+                             struct ib_umad_packet *packet, size_t count)
 {
-        ssize_t size = sizeof (packet->mad) + packet->length;
+        ssize_t size = hdr_size(file) + packet->length;
 
         if (count < size)
                 return -EINVAL;
 
-        if (copy_to_user(buf, &packet->mad, size))
+        if (copy_to_user(buf, &packet->mad, hdr_size(file)))
+                return -EFAULT;
+
+        buf += hdr_size(file);
+
+        if (copy_to_user(buf, packet->mad.data, packet->length))
                 return -EFAULT;
 
         return size;
@@ -324,7 +337,7 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
         struct ib_umad_packet *packet;
         ssize_t ret;
 
-        if (count < sizeof (struct ib_user_mad))
+        if (count < hdr_size(file))
                 return -EINVAL;
 
         spin_lock_irq(&file->recv_lock);
@@ -348,9 +361,9 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
         spin_unlock_irq(&file->recv_lock);
 
         if (packet->recv_wc)
-                ret = copy_recv_mad(buf, packet, count);
+                ret = copy_recv_mad(file, buf, packet, count);
         else
-                ret = copy_send_mad(buf, packet, count);
+                ret = copy_send_mad(file, buf, packet, count);
 
         if (ret < 0) {
                 /* Requeue packet */
@@ -442,15 +455,14 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
         __be64 *tid;
         int ret, data_len, hdr_len, copy_offset, rmpp_active;
 
-        if (count < sizeof (struct ib_user_mad) + IB_MGMT_RMPP_HDR)
+        if (count < hdr_size(file) + IB_MGMT_RMPP_HDR)
                 return -EINVAL;
 
         packet = kzalloc(sizeof *packet + IB_MGMT_RMPP_HDR, GFP_KERNEL);
         if (!packet)
                 return -ENOMEM;
 
-        if (copy_from_user(&packet->mad, buf,
-                            sizeof (struct ib_user_mad) + IB_MGMT_RMPP_HDR)) {
+        if (copy_from_user(&packet->mad, buf, hdr_size(file))) {
                 ret = -EFAULT;
                 goto err;
         }
@@ -461,6 +473,13 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
                 goto err;
         }
 
+        buf += hdr_size(file);
+
+        if (copy_from_user(packet->mad.data, buf, IB_MGMT_RMPP_HDR)) {
+                ret = -EFAULT;
+                goto err;
+        }
+
         down_read(&file->port->mutex);
 
         agent = __get_agent(file, packet->mad.hdr.id);
@@ -500,11 +519,11 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
                               IB_MGMT_RMPP_FLAG_ACTIVE;
         }
 
-        data_len = count - sizeof (struct ib_user_mad) - hdr_len;
+        data_len = count - hdr_size(file) - hdr_len;
         packet->msg = ib_create_send_mad(agent,
                                          be32_to_cpu(packet->mad.hdr.qpn),
-                                         0, rmpp_active, hdr_len,
-                                         data_len, GFP_KERNEL);
+                                         packet->mad.hdr.pkey_index, rmpp_active,
+                                         hdr_len, data_len, GFP_KERNEL);
         if (IS_ERR(packet->msg)) {
                 ret = PTR_ERR(packet->msg);
                 goto err_ah;
@@ -517,7 +536,6 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
 
         /* Copy MAD header.  Any RMPP header is already in place. */
         memcpy(packet->msg->mad, packet->mad.data, IB_MGMT_MAD_HDR);
-        buf += sizeof (struct ib_user_mad);
 
         if (!rmpp_active) {
                 if (copy_from_user(packet->msg->mad + copy_offset,
@@ -646,6 +664,16 @@ found:
                 goto out;
         }
 
+        if (!file->already_used) {
+                file->already_used = 1;
+                if (!file->use_pkey_index) {
+                        printk(KERN_WARNING "user_mad: process %s did not enable "
+                               "P_Key index support.\n", current->comm);
+                        printk(KERN_WARNING "user_mad:   Documentation/infiniband/user_mad.txt "
+                               "has info on the new ABI.\n");
+                }
+        }
+
         file->agent[agent_id] = agent;
         ret = 0;
 
@@ -682,6 +710,20 @@ out:
         return ret;
 }
 
+static long ib_umad_enable_pkey(struct ib_umad_file *file)
+{
+        int ret = 0;
+
+        down_write(&file->port->mutex);
+        if (file->already_used)
+                ret = -EINVAL;
+        else
+                file->use_pkey_index = 1;
+        up_write(&file->port->mutex);
+
+        return ret;
+}
+
 static long ib_umad_ioctl(struct file *filp, unsigned int cmd,
                           unsigned long arg)
 {
@@ -690,6 +732,8 @@ static long ib_umad_ioctl(struct file *filp, unsigned int cmd,
                 return ib_umad_reg_agent(filp->private_data, arg);
         case IB_USER_MAD_UNREGISTER_AGENT:
                 return ib_umad_unreg_agent(filp->private_data, arg);
+        case IB_USER_MAD_ENABLE_PKEY:
+                return ib_umad_enable_pkey(filp->private_data);
         default:
                 return -ENOIOCTLCMD;
         }