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>

3 files changed, 135 insertions, 29 deletions

diff --git a/Documentation/infiniband/user_mad.txt b/Documentation/infiniband/user_mad.txt
index 8ec54b974b67..744687dd195b 100644
--- a/Documentation/infiniband/user_mad.txt
+++ b/Documentation/infiniband/user_mad.txt
@@ -99,6 +99,20 @@ Transaction IDs
   request/response pairs.  The upper 32 bits are reserved for use by
   the kernel and will be overwritten before a MAD is sent.
 
+P_Key Index Handling
+
+  The old ib_umad interface did not allow setting the P_Key index for
+  MADs that are sent and did not provide a way for obtaining the P_Key
+  index of received MADs.  A new layout for struct ib_user_mad_hdr
+  with a pkey_index member has been defined; however, to preserve
+  binary compatibility with older applications, this new layout will
+  not be used unless the IB_USER_MAD_ENABLE_PKEY ioctl is called
+  before a file descriptor is used for anything else.
+
+  In September 2008, the IB_USER_MAD_ABI_VERSION will be incremented
+  to 6, the new layout of struct ib_user_mad_hdr will be used by
+  default, and the IB_USER_MAD_ENABLE_PKEY ioctl will be removed.
+
 Setting IsSM Capability Bit
 
   To set the IsSM capability bit for a port, simply open the
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;
         }
diff --git a/include/rdma/ib_user_mad.h b/include/rdma/ib_user_mad.h
index d66b15ea82c4..2a32043d1abd 100644
--- a/include/rdma/ib_user_mad.h
+++ b/include/rdma/ib_user_mad.h
@@ -52,7 +52,50 @@
  */
 
 /**
+ * ib_user_mad_hdr_old - Old version of MAD packet header without pkey_index
+ * @id - ID of agent MAD received with/to be sent with
+ * @status - 0 on successful receive, ETIMEDOUT if no response
+ *   received (transaction ID in data[] will be set to TID of original
+ *   request) (ignored on send)
+ * @timeout_ms - Milliseconds to wait for response (unset on receive)
+ * @retries - Number of automatic retries to attempt
+ * @qpn - Remote QP number received from/to be sent to
+ * @qkey - Remote Q_Key to be sent with (unset on receive)
+ * @lid - Remote lid received from/to be sent to
+ * @sl - Service level received with/to be sent with
+ * @path_bits - Local path bits received with/to be sent with
+ * @grh_present - If set, GRH was received/should be sent
+ * @gid_index - Local GID index to send with (unset on receive)
+ * @hop_limit - Hop limit in GRH
+ * @traffic_class - Traffic class in GRH
+ * @gid - Remote GID in GRH
+ * @flow_label - Flow label in GRH
+ */
+struct ib_user_mad_hdr_old {
+        __u32   id;
+        __u32   status;
+        __u32   timeout_ms;
+        __u32   retries;
+        __u32   length;
+        __be32  qpn;
+        __be32  qkey;
+        __be16  lid;
+        __u8    sl;
+        __u8    path_bits;
+        __u8    grh_present;
+        __u8    gid_index;
+        __u8    hop_limit;
+        __u8    traffic_class;
+        __u8    gid[16];
+        __be32  flow_label;
+};
+
+/**
  * ib_user_mad_hdr - MAD packet header
+ *   This layout allows specifying/receiving the P_Key index.  To use
+ *   this capability, an application must call the
+ *   IB_USER_MAD_ENABLE_PKEY ioctl on the user MAD file handle before
+ *   any other actions with the file handle.
  * @id - ID of agent MAD received with/to be sent with
  * @status - 0 on successful receive, ETIMEDOUT if no response
  *   received (transaction ID in data[] will be set to TID of original
@@ -70,6 +113,7 @@
  * @traffic_class - Traffic class in GRH
  * @gid - Remote GID in GRH
  * @flow_label - Flow label in GRH
+ * @pkey_index - P_Key index
  */
 struct ib_user_mad_hdr {
         __u32   id;
@@ -88,6 +132,8 @@ struct ib_user_mad_hdr {
         __u8    traffic_class;
         __u8    gid[16];
         __be32  flow_label;
+        __u16   pkey_index;
+        __u8    reserved[6];
 };
 
 /**
@@ -134,4 +180,6 @@ struct ib_user_mad_reg_req {
 
 #define IB_USER_MAD_UNREGISTER_AGENT    _IOW(IB_IOCTL_MAGIC, 2, __u32)
 
+#define IB_USER_MAD_ENABLE_PKEY         _IO(IB_IOCTL_MAGIC, 3)
+
 #endif /* IB_USER_MAD_H */