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net: emac: remove IBM_EMAC_RX_SKB_HEADROOM 

The EMAC driver had a custom IBM_EMAC_RX_SKB_HEADROOM
Kconfig option that reserved additional skb headroom for RX.
This patch removes the option and migrates the code
to use napi_alloc_skb() and netdev_alloc_skb_ip_align()
in its place.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christian Lamparter 2019-02-05 22:20:09 +01:00 committed by David S. Miller
parent a6e11f6bbd
commit 22087d6592
3 changed files with 47 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/net/ethernet/ibm/emac/Kconfig
View File

@ -28,18 +28,6 @@ config IBM_EMAC_RX_COPY_THRESHOLD
depends on IBM_EMAC
default "256"
config IBM_EMAC_RX_SKB_HEADROOM
int "Additional RX skb headroom (bytes)"
depends on IBM_EMAC
default "0"
help
Additional receive skb headroom. Note, that driver
will always reserve at least 2 bytes to make IP header
aligned, so usually there is no need to add any additional
headroom.
If unsure, set to 0.
config IBM_EMAC_DEBUG
bool "Debugging"
depends on IBM_EMAC

64
drivers/net/ethernet/ibm/emac/core.c
View File

@ -1071,7 +1071,9 @@ static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu)
/* Second pass, allocate new skbs */
for (i = 0; i < NUM_RX_BUFF; ++i) {
struct sk_buff *skb = alloc_skb(rx_skb_size, GFP_ATOMIC);
struct sk_buff *skb;
skb = netdev_alloc_skb_ip_align(dev->ndev, rx_skb_size);
if (!skb) {
ret = -ENOMEM;
goto oom;
@ -1080,10 +1082,10 @@ static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu)
BUG_ON(!dev->rx_skb[i]);
dev_kfree_skb(dev->rx_skb[i]);
skb_reserve(skb, EMAC_RX_SKB_HEADROOM + 2);
dev->rx_desc[i].data_ptr =
dma_map_single(&dev->ofdev->dev, skb->data - 2, rx_sync_size,
DMA_FROM_DEVICE) + 2;
dma_map_single(&dev->ofdev->dev, skb->data - NET_IP_ALIGN,
rx_sync_size, DMA_FROM_DEVICE)
+ NET_IP_ALIGN;
dev->rx_skb[i] = skb;
}
skip:
@ -1174,20 +1176,18 @@ static void emac_clean_rx_ring(struct emac_instance *dev)
}
}
static inline int emac_alloc_rx_skb(struct emac_instance *dev, int slot,
gfp_t flags)
static int
__emac_prepare_rx_skb(struct sk_buff *skb, struct emac_instance *dev, int slot)
{
struct sk_buff *skb = alloc_skb(dev->rx_skb_size, flags);
if (unlikely(!skb))
return -ENOMEM;
dev->rx_skb[slot] = skb;
dev->rx_desc[slot].data_len = 0;
skb_reserve(skb, EMAC_RX_SKB_HEADROOM + 2);
dev->rx_desc[slot].data_ptr =
dma_map_single(&dev->ofdev->dev, skb->data - 2, dev->rx_sync_size,
DMA_FROM_DEVICE) + 2;
dma_map_single(&dev->ofdev->dev, skb->data - NET_IP_ALIGN,
dev->rx_sync_size, DMA_FROM_DEVICE) + NET_IP_ALIGN;
wmb();
dev->rx_desc[slot].ctrl = MAL_RX_CTRL_EMPTY |
(slot == (NUM_RX_BUFF - 1) ? MAL_RX_CTRL_WRAP : 0);
@ -1195,6 +1195,27 @@ static inline int emac_alloc_rx_skb(struct emac_instance *dev, int slot,
return 0;
}
static int
emac_alloc_rx_skb(struct emac_instance *dev, int slot)
{
struct sk_buff *skb;
skb = __netdev_alloc_skb_ip_align(dev->ndev, dev->rx_skb_size,
GFP_KERNEL);
return __emac_prepare_rx_skb(skb, dev, slot);
}
static int
emac_alloc_rx_skb_napi(struct emac_instance *dev, int slot)
{
struct sk_buff *skb;
skb = napi_alloc_skb(&dev->mal->napi, dev->rx_skb_size);
return __emac_prepare_rx_skb(skb, dev, slot);
}
static void emac_print_link_status(struct emac_instance *dev)
{
if (netif_carrier_ok(dev->ndev))
@ -1225,7 +1246,7 @@ static int emac_open(struct net_device *ndev)
/* Allocate RX ring */
for (i = 0; i < NUM_RX_BUFF; ++i)
if (emac_alloc_rx_skb(dev, i, GFP_KERNEL)) {
if (emac_alloc_rx_skb(dev, i)) {
printk(KERN_ERR "%s: failed to allocate RX ring\n",
ndev->name);
goto oom;
@ -1660,8 +1681,9 @@ static inline void emac_recycle_rx_skb(struct emac_instance *dev, int slot,
DBG2(dev, "recycle %d %d" NL, slot, len);
if (len)
dma_map_single(&dev->ofdev->dev, skb->data - 2,
EMAC_DMA_ALIGN(len + 2), DMA_FROM_DEVICE);
dma_map_single(&dev->ofdev->dev, skb->data - NET_IP_ALIGN,
SKB_DATA_ALIGN(len + NET_IP_ALIGN),
DMA_FROM_DEVICE);
dev->rx_desc[slot].data_len = 0;
wmb();
@ -1713,7 +1735,7 @@ static inline int emac_rx_sg_append(struct emac_instance *dev, int slot)
int len = dev->rx_desc[slot].data_len;
int tot_len = dev->rx_sg_skb->len + len;
if (unlikely(tot_len + 2 > dev->rx_skb_size)) {
if (unlikely(tot_len + NET_IP_ALIGN > dev->rx_skb_size)) {
++dev->estats.rx_dropped_mtu;
dev_kfree_skb(dev->rx_sg_skb);
dev->rx_sg_skb = NULL;
@ -1769,16 +1791,18 @@ static int emac_poll_rx(void *param, int budget)
}
if (len && len < EMAC_RX_COPY_THRESH) {
struct sk_buff *copy_skb =
alloc_skb(len + EMAC_RX_SKB_HEADROOM + 2, GFP_ATOMIC);
struct sk_buff *copy_skb;
copy_skb = napi_alloc_skb(&dev->mal->napi, len);
if (unlikely(!copy_skb))
goto oom;
skb_reserve(copy_skb, EMAC_RX_SKB_HEADROOM + 2);
memcpy(copy_skb->data - 2, skb->data - 2, len + 2);
memcpy(copy_skb->data - NET_IP_ALIGN,
skb->data - NET_IP_ALIGN,
len + NET_IP_ALIGN);
emac_recycle_rx_skb(dev, slot, len);
skb = copy_skb;
} else if (unlikely(emac_alloc_rx_skb(dev, slot, GFP_ATOMIC)))
} else if (unlikely(emac_alloc_rx_skb_napi(dev, slot)))
goto oom;
skb_put(skb, len);
@ -1799,7 +1823,7 @@ static int emac_poll_rx(void *param, int budget)
sg:
if (ctrl & MAL_RX_CTRL_FIRST) {
BUG_ON(dev->rx_sg_skb);
if (unlikely(emac_alloc_rx_skb(dev, slot, GFP_ATOMIC))) {
if (unlikely(emac_alloc_rx_skb_napi(dev, slot))) {
DBG(dev, "rx OOM %d" NL, slot);
++dev->estats.rx_dropped_oom;
emac_recycle_rx_skb(dev, slot, 0);

10
drivers/net/ethernet/ibm/emac/core.h
View File

@ -68,22 +68,18 @@ static inline int emac_rx_size(int mtu)
return mal_rx_size(ETH_DATA_LEN + EMAC_MTU_OVERHEAD);
}
#define EMAC_DMA_ALIGN(x) ALIGN((x), dma_get_cache_alignment())
#define EMAC_RX_SKB_HEADROOM \
EMAC_DMA_ALIGN(CONFIG_IBM_EMAC_RX_SKB_HEADROOM)
/* Size of RX skb for the given MTU */
static inline int emac_rx_skb_size(int mtu)
{
int size = max(mtu + EMAC_MTU_OVERHEAD, emac_rx_size(mtu));
return EMAC_DMA_ALIGN(size + 2) + EMAC_RX_SKB_HEADROOM;
return SKB_DATA_ALIGN(size + NET_IP_ALIGN) + NET_SKB_PAD;
}
/* RX DMA sync size */
static inline int emac_rx_sync_size(int mtu)
{
return EMAC_DMA_ALIGN(emac_rx_size(mtu) + 2);
return SKB_DATA_ALIGN(emac_rx_size(mtu) + NET_IP_ALIGN);
}
/* Driver statistcs is split into two parts to make it more cache friendly: