On Fri, 2014-02-21 at 16:09 -0800, Dan Williams wrote:
> The usb topology after this change will have symlinks between usb3 ports
> and their usb2 peers, for example:
> 
> usb2/2-1/2-1:1.0/port1/peer => ../../../../usb3/3-1/3-1:1.0/port1
> usb2/2-1/2-1:1.0/port2/peer => ../../../../usb3/3-1/3-1:1.0/port2
> usb2/2-1/2-1:1.0/port3/peer => ../../../../usb3/3-1/3-1:1.0/port3
> usb2/2-1/2-1:1.0/port4/peer => ../../../../usb3/3-1/3-1:1.0/port4
> usb2/2-0:1.0/port1/peer     => ../../../usb3/3-0:1.0/port1
> usb2/2-0:1.0/port2/peer     => ../../../usb3/3-0:1.0/port2
> usb2/2-0:1.0/port3/peer     => ../../../usb3/3-0:1.0/port3
> usb2/2-0:1.0/port4/peer     => ../../../usb3/3-0:1.0/port4
> 
> usb3/3-1/3-1:1.0/port1/peer => ../../../../usb2/2-1/2-1:1.0/port1
> usb3/3-1/3-1:1.0/port2/peer => ../../../../usb2/2-1/2-1:1.0/port2
> usb3/3-1/3-1:1.0/port3/peer => ../../../../usb2/2-1/2-1:1.0/port3
> usb3/3-1/3-1:1.0/port4/peer => ../../../../usb2/2-1/2-1:1.0/port4
> usb3/3-0:1.0/port1/peer     => ../../../usb2/2-0:1.0/port1
> usb3/3-0:1.0/port2/peer     => ../../../usb2/2-0:1.0/port2
> usb3/3-0:1.0/port3/peer     => ../../../usb2/2-0:1.0/port3
> usb3/3-0:1.0/port4/peer     => ../../../usb2/2-0:1.0/port4
> 
> Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
> ---
>  drivers/usb/core/port.c |   45 +++++++++++++++++++++++++++++++++++++++------
>  1 files changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
> index 0b8ae73b0466..86e78bbd2e4e 100644
> --- a/drivers/usb/core/port.c
> +++ b/drivers/usb/core/port.c
> @@ -196,10 +196,11 @@ static struct usb_port *find_default_peer(struct 
> usb_hub *hub, int port1)
>       return peer;
>  }
>  
> -static void link_peers(struct usb_port *left, struct usb_port *right)
> +static int link_peers(struct usb_port *left, struct usb_port *right)
>  {
>       struct device *rdev;
>       struct device *ldev;
> +     int rc;
>  
>       if (left->peer) {
>               right = left->peer;
> @@ -209,7 +210,7 @@ static void link_peers(struct usb_port *left, struct 
> usb_port *right)
>               WARN_ONCE(1, "%s port%d already peered with %s %d\n",
>                       dev_name(ldev), left->portnum, dev_name(rdev),
>                       right->portnum);
> -             return;
> +             return -EBUSY;
>       } else if (right->peer) {
>               left = right->peer;
>               ldev = left->dev.parent->parent;
> @@ -218,13 +219,43 @@ static void link_peers(struct usb_port *left, struct 
> usb_port *right)
>               WARN_ONCE(1, "%s port%d already peered with %s %d\n",
>                       dev_name(rdev), right->portnum, dev_name(ldev),
>                       left->portnum);
> -             return;
> +             return -EBUSY;
> +     }
> +
> +     rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
> +     if (rc)
> +             return rc;
> +     rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
> +     if (rc) {
> +             sysfs_remove_link(&left->dev.kobj, "peer");
> +             return rc;
>       }
>  
>       get_device(&right->dev);
>       left->peer = right;
>       get_device(&left->dev);
>       right->peer = left;
> +
> +     return 0;
> +}
> +
> +static void link_peers_report(struct usb_port *left, struct usb_port *right)
> +{
> +     struct device *rdev = right->dev.parent->parent;
> +     struct device *ldev = left->dev.parent->parent;
> +     int rc;
> +
> +     rc = link_peers(left, right);
> +     if (rc == 0) {
> +             pr_debug("usb: link %s port%d to %s port%d\n",
> +                             dev_name(ldev), left->portnum,
> +                             dev_name(rdev), right->portnum);
> +     } else {
> +             pr_warn("usb: failed to link %s port%d to %s port%d (%d)\n",
> +                             dev_name(ldev), left->portnum,
> +                             dev_name(rdev), right->portnum, rc);
> +             pr_warn_once("usb: port power management may be unreliable\n");
> +     }
>  }

Fix this up to use dev_name(&port_dev->dev) now that the name is no
longer ambiguous.

8<------------
Subject: usb: sysfs link peer ports

From: Dan Williams <dan.j.willi...@intel.com>

The usb topology after this change will have symlinks between usb3 ports
and their usb2 peers, for example:

usb2/2-1/2-1:1.0/port1/peer => ../../../../usb3/3-1/3-1:1.0/port1
usb2/2-1/2-1:1.0/port2/peer => ../../../../usb3/3-1/3-1:1.0/port2
usb2/2-1/2-1:1.0/port3/peer => ../../../../usb3/3-1/3-1:1.0/port3
usb2/2-1/2-1:1.0/port4/peer => ../../../../usb3/3-1/3-1:1.0/port4
usb2/2-0:1.0/port1/peer     => ../../../usb3/3-0:1.0/port1
usb2/2-0:1.0/port2/peer     => ../../../usb3/3-0:1.0/port2
usb2/2-0:1.0/port3/peer     => ../../../usb3/3-0:1.0/port3
usb2/2-0:1.0/port4/peer     => ../../../usb3/3-0:1.0/port4

usb3/3-1/3-1:1.0/port1/peer => ../../../../usb2/2-1/2-1:1.0/port1
usb3/3-1/3-1:1.0/port2/peer => ../../../../usb2/2-1/2-1:1.0/port2
usb3/3-1/3-1:1.0/port3/peer => ../../../../usb2/2-1/2-1:1.0/port3
usb3/3-1/3-1:1.0/port4/peer => ../../../../usb2/2-1/2-1:1.0/port4
usb3/3-0:1.0/port1/peer     => ../../../usb2/2-0:1.0/port1
usb3/3-0:1.0/port2/peer     => ../../../usb2/2-0:1.0/port2
usb3/3-0:1.0/port3/peer     => ../../../usb2/2-0:1.0/port3
usb3/3-0:1.0/port4/peer     => ../../../usb2/2-0:1.0/port4

Introduce link_peers_report() to notify on all link_peers() failure
cases.

Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/usb/core/port.c |   41 +++++++++++++++++++++++++++++++++++------
 1 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 684941361287..2a560cd64758 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -196,10 +196,12 @@ static struct usb_port *find_default_peer(struct usb_hub 
*hub, int port1)
        return peer;
 }
 
-static void link_peers(struct usb_port *left, struct usb_port *right)
+static int link_peers(struct usb_port *left, struct usb_port *right)
 {
+       int rc;
+
        if (left->peer == right && right->peer == left)
-               return;
+               return 0;
 
        if (left->peer || right->peer) {
                struct usb_port *lpeer = left->peer;
@@ -211,13 +213,38 @@ static void link_peers(struct usb_port *left, struct 
usb_port *right)
                        lpeer ? dev_name(&lpeer->dev) : "[none]",
                        dev_name(&right->dev),
                        rpeer ? dev_name(&rpeer->dev) : "[none]");
-               return;
+               return -EBUSY;
+       }
+
+       rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
+       if (rc)
+               return rc;
+       rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
+       if (rc) {
+               sysfs_remove_link(&left->dev.kobj, "peer");
+               return rc;
        }
 
        get_device(&right->dev);
        left->peer = right;
        get_device(&left->dev);
        right->peer = left;
+
+       return 0;
+}
+
+static void link_peers_report(struct usb_port *left, struct usb_port *right)
+{
+       int rc;
+
+       rc = link_peers(left, right);
+       if (rc == 0) {
+               dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
+       } else {
+               dev_warn(&left->dev, "failed to peer to %s (%d)\n",
+                               dev_name(&right->dev), rc);
+               pr_warn_once("usb: port power management may be unreliable\n");
+       }
 }
 
 static void unlink_peers(struct usb_port *left, struct usb_port *right)
@@ -226,8 +253,10 @@ static void unlink_peers(struct usb_port *left, struct 
usb_port *right)
                        "%s and %s are not peers?\n",
                        dev_name(&left->dev), dev_name(&right->dev));
 
+       sysfs_remove_link(&left->dev.kobj, "peer");
        put_device(&left->dev);
        right->peer = NULL;
+       sysfs_remove_link(&right->dev.kobj, "peer");
        put_device(&right->dev);
        left->peer = NULL;
 }
@@ -296,7 +325,7 @@ static struct usb_port *do_default_link(struct usb_port 
*port_dev, void *p)
         * set
         */
        if (peer && !port_dev->peer)
-               link_peers(port_dev, peer);
+               link_peers_report(port_dev, peer);
        return NULL;
 }
 
@@ -362,7 +391,7 @@ void usb_set_hub_port_location(struct usb_device *hdev, int 
port1,
                enum_peer = 1;
        }
 
-       link_peers(port_dev, peer);
+       link_peers_report(port_dev, peer);
 
        /*
         * If a peer relationship was invalidated then we need to
@@ -405,7 +434,7 @@ int usb_hub_create_port_device(struct usb_hub *hub, int 
port1)
                struct usb_port *peer = find_default_peer(hub, port1);
 
                if (peer)
-                       link_peers(port_dev, peer);
+                       link_peers_report(port_dev, peer);
        }
        mutex_unlock(&peer_lock);
 


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