On Fri, Jun 5, 2020 at 6:44 PM Eric Dumazet [off-list ref] wrote:

On 6/5/20 5:00 AM, Matthew Wilcox wrote:

quoted

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

The XArray interface is easier for this driver to use.  Also fixes a
bug reported by the improper use of GFP_ATOMIC.

This does not look stable candidate.

If you try to add a Fixes: tag, you might discover that this bug is old,
and I do not believe XArray has been backported to stable branches ?


Please submit a fix suitable for old kernels (as old as v4.7)

Then when net-next is open in ~2 weeks, the Xarray stuff can be proposed.

Thanks.

Hello,

What is the status of this patch? Was it merged/superseded by another patch?
I don't see it in linux-next nor in net-net.

Thanks

quoted

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 net/qrtr/qrtr.c | 39 +++++++++++++--------------------------
 1 file changed, 13 insertions(+), 26 deletions(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 2d8d6131bc5f..488f8f326ee5 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c

@@ -20,6 +20,7 @@
 /* auto-bind range */
 #define QRTR_MIN_EPH_SOCKET 0x4000
 #define QRTR_MAX_EPH_SOCKET 0x7fff
+#define QRTR_PORT_RANGE      XA_LIMIT(QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET)

 /**
  * struct qrtr_hdr_v1 - (I|R)PCrouter packet header version 1

@@ -106,8 +107,7 @@ static LIST_HEAD(qrtr_all_nodes);
 static DEFINE_MUTEX(qrtr_node_lock);

 /* local port allocation management */
-static DEFINE_IDR(qrtr_ports);
-static DEFINE_MUTEX(qrtr_port_lock);
+static DEFINE_XARRAY_ALLOC(qrtr_ports);

 /**
  * struct qrtr_node - endpoint node

@@ -623,7 +623,7 @@ static struct qrtr_sock *qrtr_port_lookup(int port)
              port = 0;

      rcu_read_lock();
-     ipc = idr_find(&qrtr_ports, port);
+     ipc = xa_load(&qrtr_ports, port);
      if (ipc)
              sock_hold(&ipc->sk);
      rcu_read_unlock();

@@ -665,9 +665,7 @@ static void qrtr_port_remove(struct qrtr_sock *ipc)

      __sock_put(&ipc->sk);

-     mutex_lock(&qrtr_port_lock);
-     idr_remove(&qrtr_ports, port);
-     mutex_unlock(&qrtr_port_lock);
+     xa_erase(&qrtr_ports, port);

      /* Ensure that if qrtr_port_lookup() did enter the RCU read section we
       * wait for it to up increment the refcount */

@@ -688,25 +686,18 @@ static int qrtr_port_assign(struct qrtr_sock *ipc, int *port)
 {
      int rc;

-     mutex_lock(&qrtr_port_lock);
      if (!*port) {
-             rc = idr_alloc(&qrtr_ports, ipc,
-                            QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET + 1,
-                            GFP_ATOMIC);
-             if (rc >= 0)
-                     *port = rc;
+             rc = xa_alloc(&qrtr_ports, port, ipc, QRTR_PORT_RANGE,
+                             GFP_KERNEL);
      } else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) {
              rc = -EACCES;
      } else if (*port == QRTR_PORT_CTRL) {
-             rc = idr_alloc(&qrtr_ports, ipc, 0, 1, GFP_ATOMIC);
+             rc = xa_insert(&qrtr_ports, 0, ipc, GFP_KERNEL);
      } else {
-             rc = idr_alloc(&qrtr_ports, ipc, *port, *port + 1, GFP_ATOMIC);
-             if (rc >= 0)
-                     *port = rc;
+             rc = xa_insert(&qrtr_ports, *port, ipc, GFP_KERNEL);
      }
-     mutex_unlock(&qrtr_port_lock);

-     if (rc == -ENOSPC)
+     if (rc == -EBUSY)
              return -EADDRINUSE;
      else if (rc < 0)
              return rc;

@@ -720,20 +711,16 @@ static int qrtr_port_assign(struct qrtr_sock *ipc, int *port)
 static void qrtr_reset_ports(void)
 {
      struct qrtr_sock *ipc;
-     int id;
-
-     mutex_lock(&qrtr_port_lock);
-     idr_for_each_entry(&qrtr_ports, ipc, id) {
-             /* Don't reset control port */
-             if (id == 0)
-                     continue;
+     unsigned long index;

+     rcu_read_lock();
+     xa_for_each_start(&qrtr_ports, index, ipc, 1) {
              sock_hold(&ipc->sk);
              ipc->sk.sk_err = ENETRESET;
              ipc->sk.sk_error_report(&ipc->sk);
              sock_put(&ipc->sk);
      }
-     mutex_unlock(&qrtr_port_lock);
+     rcu_read_unlock();
 }

 /* Bind socket to address.