Staging: hv: netvsc: Fix a bug in accounting transmit slots
The transmit slots were manipulated without proper locking. Fix this bug by
making the variable tracking the transmit slots atomic.
This patch should be ported to prior stable kernels 2.6.32 and later.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/hv/netvsc_drv.c b/drivers/staging/hv/netvsc_drv.c
index 33cab9c..38ca2c2 100644
--- a/drivers/staging/hv/netvsc_drv.c
+++ b/drivers/staging/hv/netvsc_drv.c
@@ -21,6 +21,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
+#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/device.h>
@@ -45,7 +46,7 @@
struct net_device_context {
/* point back to our device context */
struct hv_device *device_ctx;
- unsigned long avail;
+ atomic_t avail;
struct delayed_work dwork;
};
@@ -118,8 +119,9 @@
dev_kfree_skb_any(skb);
- net_device_ctx->avail += num_pages;
- if (net_device_ctx->avail >= PACKET_PAGES_HIWATER)
+ atomic_add(num_pages, &net_device_ctx->avail);
+ if (atomic_read(&net_device_ctx->avail) >=
+ PACKET_PAGES_HIWATER)
netif_wake_queue(net);
}
}
@@ -133,7 +135,7 @@
/* Add 1 for skb->data and additional one for RNDIS */
num_pages = skb_shinfo(skb)->nr_frags + 1 + 1;
- if (num_pages > net_device_ctx->avail)
+ if (num_pages > atomic_read(&net_device_ctx->avail))
return NETDEV_TX_BUSY;
/* Allocate a netvsc packet based on # of frags. */
@@ -185,8 +187,8 @@
net->stats.tx_bytes += skb->len;
net->stats.tx_packets++;
- net_device_ctx->avail -= num_pages;
- if (net_device_ctx->avail < PACKET_PAGES_LOWATER)
+ atomic_sub(num_pages, &net_device_ctx->avail);
+ if (atomic_read(&net_device_ctx->avail) < PACKET_PAGES_LOWATER)
netif_stop_queue(net);
} else {
/* we are shutting down or bus overloaded, just drop packet */
@@ -345,7 +347,7 @@
net_device_ctx = netdev_priv(net);
net_device_ctx->device_ctx = dev;
- net_device_ctx->avail = ring_size;
+ atomic_set(&net_device_ctx->avail, ring_size);
dev_set_drvdata(&dev->device, net);
INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_send_garp);
