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Date: Fri, 26 Apr 2013 11:41:21 +0300 (EEST)
From: Petko Manolov <petkan@...leusys.com>
To: David Miller <davem@...emloft.net>
cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] drivers: net: usb: pegasus: remove skb pool
From: Petko Manolov <petkan@...leusys.com>
The socket buffer pool for the receive path is now gone. It's existence
didn't make much difference (performance-wise) and the code is better off
without the spinlocks protecting it.
Signed-off-by: Petko Manolov <petkan@...leusys.com>
---
Diff made against latest net-next, not my git repository;
drivers/net/usb/pegasus.c | 73 +++++------------------------------
drivers/net/usb/pegasus.h | 3 --
2 files changed, 9 insertions(+), 67 deletions(-)
diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index 73051d1..ff7b84d 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -575,51 +575,6 @@ static int enable_net_traffic(struct net_device *dev, struct usb_device *usb)
return ret;
}
-static void fill_skb_pool(pegasus_t *pegasus)
-{
- int i;
-
- for (i = 0; i < RX_SKBS; i++) {
- if (pegasus->rx_pool[i])
- continue;
- pegasus->rx_pool[i] = dev_alloc_skb(PEGASUS_MTU + 2);
- /*
- ** we give up if the allocation fail. the tasklet will be
- ** rescheduled again anyway...
- */
- if (pegasus->rx_pool[i] == NULL)
- return;
- skb_reserve(pegasus->rx_pool[i], 2);
- }
-}
-
-static void free_skb_pool(pegasus_t *pegasus)
-{
- int i;
-
- for (i = 0; i < RX_SKBS; i++) {
- if (pegasus->rx_pool[i]) {
- dev_kfree_skb(pegasus->rx_pool[i]);
- pegasus->rx_pool[i] = NULL;
- }
- }
-}
-
-static inline struct sk_buff *pull_skb(pegasus_t * pegasus)
-{
- int i;
- struct sk_buff *skb;
-
- for (i = 0; i < RX_SKBS; i++) {
- if (likely(pegasus->rx_pool[i] != NULL)) {
- skb = pegasus->rx_pool[i];
- pegasus->rx_pool[i] = NULL;
- return skb;
- }
- }
- return NULL;
-}
-
static void read_bulk_callback(struct urb *urb)
{
pegasus_t *pegasus = urb->context;
@@ -704,9 +659,8 @@ static void read_bulk_callback(struct urb *urb)
if (pegasus->flags & PEGASUS_UNPLUG)
return;
- spin_lock(&pegasus->rx_pool_lock);
- pegasus->rx_skb = pull_skb(pegasus);
- spin_unlock(&pegasus->rx_pool_lock);
+ pegasus->rx_skb = __netdev_alloc_skb_ip_align(pegasus->net, PEGASUS_MTU,
+ GFP_ATOMIC);
if (pegasus->rx_skb == NULL)
goto tl_sched;
@@ -734,24 +688,23 @@ tl_sched:
static void rx_fixup(unsigned long data)
{
pegasus_t *pegasus;
- unsigned long flags;
int status;
pegasus = (pegasus_t *) data;
if (pegasus->flags & PEGASUS_UNPLUG)
return;
- spin_lock_irqsave(&pegasus->rx_pool_lock, flags);
- fill_skb_pool(pegasus);
if (pegasus->flags & PEGASUS_RX_URB_FAIL)
if (pegasus->rx_skb)
goto try_again;
if (pegasus->rx_skb == NULL)
- pegasus->rx_skb = pull_skb(pegasus);
+ pegasus->rx_skb = __netdev_alloc_skb_ip_align(pegasus->net,
+ PEGASUS_MTU,
+ GFP_ATOMIC);
if (pegasus->rx_skb == NULL) {
netif_warn(pegasus, rx_err, pegasus->net, "low on memory\n");
tasklet_schedule(&pegasus->rx_tl);
- goto done;
+ return;
}
usb_fill_bulk_urb(pegasus->rx_urb, pegasus->usb,
usb_rcvbulkpipe(pegasus->usb, 1),
@@ -767,8 +720,6 @@ try_again:
} else {
pegasus->flags &= ~PEGASUS_RX_URB_FAIL;
}
-done:
- spin_unlock_irqrestore(&pegasus->rx_pool_lock, flags);
}
static void write_bulk_callback(struct urb *urb)
@@ -1007,10 +958,9 @@ static int pegasus_open(struct net_device *net)
int res;
if (pegasus->rx_skb == NULL)
- pegasus->rx_skb = pull_skb(pegasus);
- /*
- ** Note: no point to free the pool. it is empty :-)
- */
+ pegasus->rx_skb = __netdev_alloc_skb_ip_align(pegasus->net,
+ PEGASUS_MTU,
+ GFP_KERNEL);
if (!pegasus->rx_skb)
return -ENOMEM;
@@ -1044,7 +994,6 @@ static int pegasus_open(struct net_device *net)
res = -EIO;
usb_kill_urb(pegasus->rx_urb);
usb_kill_urb(pegasus->intr_urb);
- free_skb_pool(pegasus);
goto exit;
}
set_carrier(net);
@@ -1364,7 +1313,6 @@ static int pegasus_probe(struct usb_interface *intf,
pegasus->mii.mdio_write = mdio_write;
pegasus->mii.phy_id_mask = 0x1f;
pegasus->mii.reg_num_mask = 0x1f;
- spin_lock_init(&pegasus->rx_pool_lock);
pegasus->msg_enable = netif_msg_init(msg_level, NETIF_MSG_DRV
| NETIF_MSG_PROBE | NETIF_MSG_LINK);
@@ -1376,7 +1324,6 @@ static int pegasus_probe(struct usb_interface *intf,
goto out2;
}
set_ethernet_addr(pegasus);
- fill_skb_pool(pegasus);
if (pegasus->features & PEGASUS_II) {
dev_info(&intf->dev, "setup Pegasus II specific registers\n");
setup_pegasus_II(pegasus);
@@ -1404,7 +1351,6 @@ static int pegasus_probe(struct usb_interface *intf,
out3:
usb_set_intfdata(intf, NULL);
- free_skb_pool(pegasus);
out2:
free_all_urbs(pegasus);
out1:
@@ -1429,7 +1375,6 @@ static void pegasus_disconnect(struct usb_interface *intf)
unregister_netdev(pegasus->net);
unlink_all_urbs(pegasus);
free_all_urbs(pegasus);
- free_skb_pool(pegasus);
if (pegasus->rx_skb != NULL) {
dev_kfree_skb(pegasus->rx_skb);
pegasus->rx_skb = NULL;
diff --git a/drivers/net/usb/pegasus.h b/drivers/net/usb/pegasus.h
index 65b78b3..00d44e3 100644
--- a/drivers/net/usb/pegasus.h
+++ b/drivers/net/usb/pegasus.h
@@ -13,7 +13,6 @@
#define HAS_HOME_PNA 0x40000000
#define PEGASUS_MTU 1536
-#define RX_SKBS 4
#define EPROM_WRITE 0x01
#define EPROM_READ 0x02
@@ -97,11 +96,9 @@ typedef struct pegasus {
struct tasklet_struct rx_tl;
struct delayed_work carrier_check;
struct urb *ctrl_urb, *rx_urb, *tx_urb, *intr_urb;
- struct sk_buff *rx_pool[RX_SKBS];
struct sk_buff *rx_skb;
struct usb_ctrlrequest dr;
wait_queue_head_t ctrl_wait;
- spinlock_t rx_pool_lock;
int chip;
unsigned char intr_buff[8];
__u8 tx_buff[PEGASUS_MTU];
--
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