xen/blkback: Make optional features be really optional.

They were using the xenbus_dev_fatal() function which would
change the state of the connection immediately. Which is not
what we want when we advertise optional features.

So make 'feature-discard','feature-barrier','feature-flush-cache'
optional.

Suggested-by: Jan Beulich <JBeulich@suse.com>
[v1: Made the discard function void and static]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index d417c13..89860f3 100644 (file)
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -381,12 +381,12 @@ int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
        err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache",
                            "%d", state);
        if (err)
-               xenbus_dev_fatal(dev, err, "writing feature-flush-cache");
+               dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err);
 
        return err;
 }
 
-int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
+static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
 {
        struct xenbus_device *dev = be->dev;
        struct xen_blkif *blkif = be->blkif;
@@ -400,17 +400,15 @@ int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
                        "discard-granularity", "%u",
                        q->limits.discard_granularity);
                if (err) {
-                       xenbus_dev_fatal(dev, err,
-                               "writing discard-granularity");
-                       goto out;
+                       dev_warn(&dev->dev, "writing discard-granularity (%d)", err);
+                       return;
                }
                err = xenbus_printf(xbt, dev->nodename,
                        "discard-alignment", "%u",
                        q->limits.discard_alignment);
                if (err) {
-                       xenbus_dev_fatal(dev, err,
-                               "writing discard-alignment");
-                       goto out;
+                       dev_warn(&dev->dev, "writing discard-alignment (%d)", err);
+                       return;
                }
                state = 1;
                /* Optional. */
@@ -418,17 +416,14 @@ int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
                                    "discard-secure", "%d",
                                    blkif->vbd.discard_secure);
                if (err) {
-                       xenbus_dev_fatal(dev, err,
-                                       "writting discard-secure");
-                       goto out;
+                       dev_warn(dev-dev, "writing discard-secure (%d)", err);
+                       return;
                }
        }
        err = xenbus_printf(xbt, dev->nodename, "feature-discard",
                            "%d", state);
        if (err)
-               xenbus_dev_fatal(dev, err, "writing feature-discard");
-out:
-       return err;
+               dev_warn(&dev->dev, "writing feature-discard (%d)", err);
 }
 int xen_blkbk_barrier(struct xenbus_transaction xbt,
                      struct backend_info *be, int state)
@@ -439,7 +434,7 @@ int xen_blkbk_barrier(struct xenbus_transaction xbt,
        err = xenbus_printf(xbt, dev->nodename, "feature-barrier",
                            "%d", state);
        if (err)
-               xenbus_dev_fatal(dev, err, "writing feature-barrier");
+               dev_warn(&dev->dev, "writing feature-barrier (%d)", err);
 
        return err;
 }
@@ -671,14 +666,12 @@ again:
                return;
        }
 
-       err = xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support);
-       if (err)
-               goto abort;
+       /* If we can't advertise it is OK. */
+       xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support);
 
-       err = xen_blkbk_discard(xbt, be);
+       xen_blkbk_discard(xbt, be);
 
-       /* If we can't advertise it is OK. */
-       err = xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
+       xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
 
        err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
                            (unsigned long long)vbd_sz(&be->blkif->vbd));