korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 21:38:32 +08:00
Code Issues Packages Projects Releases Wiki Activity

ibmvnic: Reduce memcpys in tx descriptor generation

Browse Source 
Previously when creating the header descriptors, the driver would:
1. allocate a temporary buffer on the stack (in build_hdr_descs_arr)
2. memcpy the header info into the temporary buffer (in build_hdr_data)
3. memcpy the temp buffer into a local variable (in create_hdr_descs)
4. copy the local variable into the return buffer (in create_hdr_descs)

Since, there is no opportunity for errors during this process, the temp
buffer is not needed and work can be done on the return buffer directly.

Repurpose build_hdr_data() to only calculate the header lengths. Rename
it to get_hdr_lens().
Edit create_hdr_descs() to read from the skb directly and copy directly
into the returned useful buffer.

The process now involves less memory and write operations while
also being more readable.

Signed-off-by: Nick Child <nnac123@linux.ibm.com>
Link: https://patch.msgid.link/20240807211809.1259563-4-nnac123@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Nick Child 2024-08-07 16:18:05 -05:00 committed by Jakub Kicinski
parent b41b45ecee
commit d95f749a0b
1 changed files with 40 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

89
drivers/net/ethernet/ibm/ibmvnic.c
View File

@ -2140,23 +2140,36 @@ static int ibmvnic_close(struct net_device *netdev)
}
/**
* build_hdr_data - creates L2/L3/L4 header data buffer
* get_hdr_lens - fills list of L2/L3/L4 hdr lens
* @hdr_field: bitfield determining needed headers
* @skb: socket buffer
* @hdr_len: array of header lengths
* @hdr_data: buffer to write the header to
* @hdr_len: array of header lengths to be filled
*
* Reads hdr_field to determine which headers are needed by firmware.
* Builds a buffer containing these headers. Saves individual header
* lengths and total buffer length to be used to build descriptors.
*
* Return: total len of all headers
*/
static int build_hdr_data(u8 hdr_field, struct sk_buff *skb,
int *hdr_len, u8 *hdr_data)
static int get_hdr_lens(u8 hdr_field, struct sk_buff *skb,
int *hdr_len)
{
int len = 0;
u8 *hdr;
if ((hdr_field >> 6) & 1) {
hdr_len[0] = skb_mac_header_len(skb);
len += hdr_len[0];
}
if ((hdr_field >> 5) & 1) {
hdr_len[1] = skb_network_header_len(skb);
len += hdr_len[1];
}
if (!((hdr_field >> 4) & 1))
return len;
if (skb->protocol == htons(ETH_P_IP)) {
if (ip_hdr(skb)->protocol == IPPROTO_TCP)
hdr_len[2] = tcp_hdrlen(skb);
@ -2169,27 +2182,7 @@ static int build_hdr_data(u8 hdr_field, struct sk_buff *skb,
hdr_len[2] = sizeof(struct udphdr);
}
if ((hdr_field >> 6) & 1) {
hdr_len[0] = skb_mac_header_len(skb);
hdr = skb_mac_header(skb);
memcpy(hdr_data, hdr, hdr_len[0]);
len += hdr_len[0];
}
if ((hdr_field >> 5) & 1) {
hdr_len[1] = skb_network_header_len(skb);
hdr = skb_network_header(skb);
memcpy(hdr_data + len, hdr, hdr_len[1]);
len += hdr_len[1];
}
if ((hdr_field >> 4) & 1) {
hdr = skb_transport_header(skb);
memcpy(hdr_data + len, hdr, hdr_len[2]);
len += hdr_len[2];
}
return len;
return len + hdr_len[2];
}
/**
@ -2202,12 +2195,14 @@ static int build_hdr_data(u8 hdr_field, struct sk_buff *skb,
*
* Creates header and, if needed, header extension descriptors and
* places them in a descriptor array, scrq_arr
*
* Return: Number of header descs
*/
static int create_hdr_descs(u8 hdr_field, u8 *hdr_data, int len, int *hdr_len,
union sub_crq *scrq_arr)
{
union sub_crq hdr_desc;
union sub_crq *hdr_desc;
int tmp_len = len;
int num_descs = 0;
u8 *data, *cur;
@ -2216,28 +2211,26 @@ static int create_hdr_descs(u8 hdr_field, u8 *hdr_data, int len, int *hdr_len,
while (tmp_len > 0) {
cur = hdr_data + len - tmp_len;
memset(&hdr_desc, 0, sizeof(hdr_desc));
if (cur != hdr_data) {
data = hdr_desc.hdr_ext.data;
hdr_desc = &scrq_arr[num_descs];
if (num_descs) {
data = hdr_desc->hdr_ext.data;
tmp = tmp_len > 29 ? 29 : tmp_len;
hdr_desc.hdr_ext.first = IBMVNIC_CRQ_CMD;
hdr_desc.hdr_ext.type = IBMVNIC_HDR_EXT_DESC;
hdr_desc.hdr_ext.len = tmp;
hdr_desc->hdr_ext.first = IBMVNIC_CRQ_CMD;
hdr_desc->hdr_ext.type = IBMVNIC_HDR_EXT_DESC;
hdr_desc->hdr_ext.len = tmp;
} else {
data = hdr_desc.hdr.data;
data = hdr_desc->hdr.data;
tmp = tmp_len > 24 ? 24 : tmp_len;
hdr_desc.hdr.first = IBMVNIC_CRQ_CMD;
hdr_desc.hdr.type = IBMVNIC_HDR_DESC;
hdr_desc.hdr.len = tmp;
hdr_desc.hdr.l2_len = (u8)hdr_len[0];
hdr_desc.hdr.l3_len = cpu_to_be16((u16)hdr_len[1]);
hdr_desc.hdr.l4_len = (u8)hdr_len[2];
hdr_desc.hdr.flag = hdr_field << 1;
hdr_desc->hdr.first = IBMVNIC_CRQ_CMD;
hdr_desc->hdr.type = IBMVNIC_HDR_DESC;
hdr_desc->hdr.len = tmp;
hdr_desc->hdr.l2_len = (u8)hdr_len[0];
hdr_desc->hdr.l3_len = cpu_to_be16((u16)hdr_len[1]);
hdr_desc->hdr.l4_len = (u8)hdr_len[2];
hdr_desc->hdr.flag = hdr_field << 1;
}
memcpy(data, cur, tmp);
tmp_len -= tmp;
*scrq_arr = hdr_desc;
scrq_arr++;
num_descs++;
}
@ -2260,13 +2253,11 @@ static void build_hdr_descs_arr(struct sk_buff *skb,
int *num_entries, u8 hdr_field)
{
int hdr_len[3] = {0, 0, 0};
u8 hdr_data[140] = {0};
int tot_len;
tot_len = build_hdr_data(hdr_field, skb, hdr_len,
hdr_data);
*num_entries += create_hdr_descs(hdr_field, hdr_data, tot_len, hdr_len,
indir_arr + 1);
tot_len = get_hdr_lens(hdr_field, skb, hdr_len);
*num_entries += create_hdr_descs(hdr_field, skb_mac_header(skb),
tot_len, hdr_len, indir_arr + 1);
}
static int ibmvnic_xmit_workarounds(struct sk_buff *skb,