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r8152: support skb_add_rx_frag
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Use skb_add_rx_frag() to reduce the memory copy for rx data.

Use a new list of rx_used to store the rx buffer which couldn't be
reused yet.

Besides, the total number of rx buffer may be increased or decreased
dynamically. And it is limited by RTL8152_MAX_RX_AGG.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
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Hayes Wang authored and Jakub Kicinski committed Aug 14, 2019
1 parent d55d708 commit 47922fc
Showing 1 changed file with 105 additions and 15 deletions.
120 changes: 105 additions & 15 deletions drivers/net/usb/r8152.c
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Original file line number Diff line number Diff line change
Expand Up @@ -584,6 +584,9 @@ enum rtl_register_content {
#define TX_ALIGN 4
#define RX_ALIGN 8

#define RTL8152_MAX_RX_AGG (10 * RTL8152_MAX_RX)
#define RTL8152_RXFG_HEADSZ 256

#define INTR_LINK 0x0004

#define RTL8152_REQT_READ 0xc0
Expand Down Expand Up @@ -720,7 +723,7 @@ struct r8152 {
struct net_device *netdev;
struct urb *intr_urb;
struct tx_agg tx_info[RTL8152_MAX_TX];
struct list_head rx_info;
struct list_head rx_info, rx_used;
struct list_head rx_done, tx_free;
struct sk_buff_head tx_queue, rx_queue;
spinlock_t rx_lock, tx_lock;
Expand Down Expand Up @@ -1476,7 +1479,7 @@ static void free_rx_agg(struct r8152 *tp, struct rx_agg *agg)
list_del(&agg->info_list);

usb_free_urb(agg->urb);
__free_pages(agg->page, get_order(tp->rx_buf_sz));
put_page(agg->page);
kfree(agg);

atomic_dec(&tp->rx_count);
Expand All @@ -1494,7 +1497,7 @@ static struct rx_agg *alloc_rx_agg(struct r8152 *tp, gfp_t mflags)
if (!rx_agg)
return NULL;

rx_agg->page = alloc_pages(mflags, order);
rx_agg->page = alloc_pages(mflags | __GFP_COMP, order);
if (!rx_agg->page)
goto free_rx;

Expand Down Expand Up @@ -1947,6 +1950,46 @@ static u8 r8152_rx_csum(struct r8152 *tp, struct rx_desc *rx_desc)
return checksum;
}

static inline bool rx_count_exceed(struct r8152 *tp)
{
return atomic_read(&tp->rx_count) > RTL8152_MAX_RX;
}

static inline int agg_offset(struct rx_agg *agg, void *addr)
{
return (int)(addr - agg->buffer);
}

static struct rx_agg *rtl_get_free_rx(struct r8152 *tp, gfp_t mflags)
{
struct rx_agg *agg, *agg_next, *agg_free = NULL;
unsigned long flags;

spin_lock_irqsave(&tp->rx_lock, flags);

list_for_each_entry_safe(agg, agg_next, &tp->rx_used, list) {
if (page_count(agg->page) == 1) {
if (!agg_free) {
list_del_init(&agg->list);
agg_free = agg;
continue;
}
if (rx_count_exceed(tp)) {
list_del_init(&agg->list);
free_rx_agg(tp, agg);
}
break;
}
}

spin_unlock_irqrestore(&tp->rx_lock, flags);

if (!agg_free && atomic_read(&tp->rx_count) < RTL8152_MAX_RX_AGG)
agg_free = alloc_rx_agg(tp, mflags);

return agg_free;
}

static int rx_bottom(struct r8152 *tp, int budget)
{
unsigned long flags;
Expand Down Expand Up @@ -1982,7 +2025,7 @@ static int rx_bottom(struct r8152 *tp, int budget)

list_for_each_safe(cursor, next, &rx_queue) {
struct rx_desc *rx_desc;
struct rx_agg *agg;
struct rx_agg *agg, *agg_free;
int len_used = 0;
struct urb *urb;
u8 *rx_data;
Expand All @@ -1994,14 +2037,16 @@ static int rx_bottom(struct r8152 *tp, int budget)
if (urb->actual_length < ETH_ZLEN)
goto submit;

agg_free = rtl_get_free_rx(tp, GFP_ATOMIC);

rx_desc = agg->buffer;
rx_data = agg->buffer;
len_used += sizeof(struct rx_desc);

while (urb->actual_length > len_used) {
struct net_device *netdev = tp->netdev;
struct net_device_stats *stats = &netdev->stats;
unsigned int pkt_len;
unsigned int pkt_len, rx_frag_head_sz;
struct sk_buff *skb;

/* limite the skb numbers for rx_queue */
Expand All @@ -2019,33 +2064,62 @@ static int rx_bottom(struct r8152 *tp, int budget)
pkt_len -= ETH_FCS_LEN;
rx_data += sizeof(struct rx_desc);

skb = napi_alloc_skb(napi, pkt_len);
if (!agg_free || RTL8152_RXFG_HEADSZ > pkt_len)
rx_frag_head_sz = pkt_len;
else
rx_frag_head_sz = RTL8152_RXFG_HEADSZ;

skb = napi_alloc_skb(napi, rx_frag_head_sz);
if (!skb) {
stats->rx_dropped++;
goto find_next_rx;
}

skb->ip_summed = r8152_rx_csum(tp, rx_desc);
memcpy(skb->data, rx_data, pkt_len);
skb_put(skb, pkt_len);
memcpy(skb->data, rx_data, rx_frag_head_sz);
skb_put(skb, rx_frag_head_sz);
pkt_len -= rx_frag_head_sz;
rx_data += rx_frag_head_sz;
if (pkt_len) {
skb_add_rx_frag(skb, 0, agg->page,
agg_offset(agg, rx_data),
pkt_len,
SKB_DATA_ALIGN(pkt_len));
get_page(agg->page);
}

skb->protocol = eth_type_trans(skb, netdev);
rtl_rx_vlan_tag(rx_desc, skb);
if (work_done < budget) {
napi_gro_receive(napi, skb);
work_done++;
stats->rx_packets++;
stats->rx_bytes += pkt_len;
stats->rx_bytes += skb->len;
} else {
__skb_queue_tail(&tp->rx_queue, skb);
}

find_next_rx:
rx_data = rx_agg_align(rx_data + pkt_len + ETH_FCS_LEN);
rx_desc = (struct rx_desc *)rx_data;
len_used = (int)(rx_data - (u8 *)agg->buffer);
len_used = agg_offset(agg, rx_data);
len_used += sizeof(struct rx_desc);
}

WARN_ON(!agg_free && page_count(agg->page) > 1);

if (agg_free) {
spin_lock_irqsave(&tp->rx_lock, flags);
if (page_count(agg->page) == 1) {
list_add(&agg_free->list, &tp->rx_used);
} else {
list_add_tail(&agg->list, &tp->rx_used);
agg = agg_free;
urb = agg->urb;
}
spin_unlock_irqrestore(&tp->rx_lock, flags);
}

submit:
if (!ret) {
ret = r8152_submit_rx(tp, agg, GFP_ATOMIC);
Expand Down Expand Up @@ -2373,13 +2447,14 @@ static int rtl_start_rx(struct r8152 *tp)
struct rx_agg *agg, *agg_next;
struct list_head tmp_list;
unsigned long flags;
int ret = 0;
int ret = 0, i = 0;

INIT_LIST_HEAD(&tmp_list);

spin_lock_irqsave(&tp->rx_lock, flags);

INIT_LIST_HEAD(&tp->rx_done);
INIT_LIST_HEAD(&tp->rx_used);

list_splice_init(&tp->rx_info, &tmp_list);

Expand All @@ -2388,10 +2463,18 @@ static int rtl_start_rx(struct r8152 *tp)
list_for_each_entry_safe(agg, agg_next, &tmp_list, info_list) {
INIT_LIST_HEAD(&agg->list);

if (ret < 0)
/* Only RTL8152_MAX_RX rx_agg need to be submitted. */
if (++i > RTL8152_MAX_RX) {
spin_lock_irqsave(&tp->rx_lock, flags);
list_add_tail(&agg->list, &tp->rx_used);
spin_unlock_irqrestore(&tp->rx_lock, flags);
} else if (unlikely(ret < 0)) {
spin_lock_irqsave(&tp->rx_lock, flags);
list_add_tail(&agg->list, &tp->rx_done);
else
spin_unlock_irqrestore(&tp->rx_lock, flags);
} else {
ret = r8152_submit_rx(tp, agg, GFP_KERNEL);
}
}

spin_lock_irqsave(&tp->rx_lock, flags);
Expand Down Expand Up @@ -2420,8 +2503,15 @@ static int rtl_stop_rx(struct r8152 *tp)
list_splice_init(&tp->rx_info, &tmp_list);
spin_unlock_irqrestore(&tp->rx_lock, flags);

list_for_each_entry_safe(agg, agg_next, &tmp_list, info_list)
usb_kill_urb(agg->urb);
list_for_each_entry_safe(agg, agg_next, &tmp_list, info_list) {
/* At least RTL8152_MAX_RX rx_agg have the page_count being
* equal to 1, so the other ones could be freed safely.
*/
if (page_count(agg->page) > 1)
free_rx_agg(tp, agg);
else
usb_kill_urb(agg->urb);
}

/* Move back the list of temp to the rx_info */
spin_lock_irqsave(&tp->rx_lock, flags);
Expand Down

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