[PATCH 5.10 157/158] qrtr: Convert qrtr_ports from IDR to XArray

From: Greg Kroah-Hartman
Date: Tue Aug 23 2022 - 08:30:23 EST


From: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>

commit 3cbf7530a163d048a6376cd22fecb9cdcb23b192 upstream.

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

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Stanislav Goriainov <goriainov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/qrtr/qrtr.c | 42 ++++++++++++++----------------------------
1 file changed, 14 insertions(+), 28 deletions(-)

--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -20,6 +20,8 @@
/* auto-bind range */
#define QRTR_MIN_EPH_SOCKET 0x4000
#define QRTR_MAX_EPH_SOCKET 0x7fff
+#define QRTR_EPH_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 +108,7 @@ 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
@@ -635,7 +636,7 @@ static struct qrtr_sock *qrtr_port_looku
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();
@@ -677,9 +678,7 @@ static void qrtr_port_remove(struct qrtr

__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 */
@@ -698,29 +697,20 @@ static void qrtr_port_remove(struct qrtr
*/
static int qrtr_port_assign(struct qrtr_sock *ipc, int *port)
{
- u32 min_port;
int rc;

- mutex_lock(&qrtr_port_lock);
if (!*port) {
- min_port = QRTR_MIN_EPH_SOCKET;
- rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, QRTR_MAX_EPH_SOCKET, GFP_ATOMIC);
- if (!rc)
- *port = min_port;
+ rc = xa_alloc(&qrtr_ports, port, ipc, QRTR_EPH_PORT_RANGE,
+ GFP_KERNEL);
} else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) {
rc = -EACCES;
} else if (*port == QRTR_PORT_CTRL) {
- min_port = 0;
- rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, 0, GFP_ATOMIC);
+ rc = xa_insert(&qrtr_ports, 0, ipc, GFP_KERNEL);
} else {
- min_port = *port;
- rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, *port, GFP_ATOMIC);
- if (!rc)
- *port = min_port;
+ 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;
@@ -734,20 +724,16 @@ static int qrtr_port_assign(struct qrtr_
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.