rapidio: add lock protection for doorbell list

Add lock protection around doorbell list handling to prevent list
corruption on SMP platforms.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 8 insertions, 3 deletions

diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c
index 03b8c5af72bb..e42f97e9e62a 100644
--- a/drivers/rapidio/rio.c
+++ b/drivers/rapidio/rio.c
@@ -362,7 +362,9 @@ rio_setup_inb_dbell(struct rio_mport *mport, void *dev_id, struct resource *res,
         dbell->dinb = dinb;
         dbell->dev_id = dev_id;
 
+        mutex_lock(&mport->lock);
         list_add_tail(&dbell->node, &mport->dbells);
+        mutex_unlock(&mport->lock);
 
       out:
         return rc;
@@ -426,12 +428,15 @@ int rio_release_inb_dbell(struct rio_mport *mport, u16 start, u16 end)
         int rc = 0, found = 0;
         struct rio_dbell *dbell;
 
+        mutex_lock(&mport->lock);
         list_for_each_entry(dbell, &mport->dbells, node) {
                 if ((dbell->res->start == start) && (dbell->res->end == end)) {
+                        list_del(&dbell->node);
                         found = 1;
                         break;
                 }
         }
+        mutex_unlock(&mport->lock);
 
         /* If we can't find an exact match, fail */
         if (!found) {
@@ -439,9 +444,6 @@ int rio_release_inb_dbell(struct rio_mport *mport, u16 start, u16 end)
                 goto out;
         }
 
-        /* Delete from list */
-        list_del(&dbell->node);
-
         /* Release the doorbell resource */
         rc = release_resource(dbell->res);
 
@@ -2024,6 +2026,7 @@ int rio_mport_initialize(struct rio_mport *mport)
         mport->id = next_portid++;
         mport->host_deviceid = rio_get_hdid(mport->id);
         mport->nscan = NULL;
+        mutex_init(&mport->lock);
 
         return 0;
 }
diff --git a/include/linux/rio.h b/include/linux/rio.h
index f833773cdc68..948f60550ae5 100644
--- a/include/linux/rio.h
+++ b/include/linux/rio.h
@@ -248,6 +248,7 @@ enum rio_phy_type {
  * @node: Node in global list of master ports
  * @nnode: Node in network list of master ports
  * @net: RIO net this mport is attached to
+ * @lock: lock to synchronize lists manipulations
  * @iores: I/O mem resource that this master port interface owns
  * @riores: RIO resources that this master port interfaces owns
  * @inb_msg: RIO inbound message event descriptors
@@ -271,6 +272,7 @@ struct rio_mport {
         struct list_head node;  /* node in global list of ports */
         struct list_head nnode; /* node in net list of ports */
         struct rio_net *net;    /* RIO net this mport is attached to */
+        struct mutex lock;
         struct resource iores;
         struct resource riores[RIO_MAX_MPORT_RESOURCES];
         struct rio_msg inb_msg[RIO_MAX_MBOX];