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LinuxKPI: skbuff: handle dev_alloc_skb() correctly

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dev_alloc_skb() comapred to alloc_skb() reserves some headroom
at the beginning of the skb which is used by drivers.
Split the code for the two cases and reserve NET_SKB_PAD space,
which should at least be 32 octets.

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
This commit is contained in:
Bjoern A. Zeeb 2022-04-07 18:06:55 +00:00
parent 7354782698
commit 9df5f29caf
2 changed files with 24 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/compat/linuxkpi/common/include/linux/skbuff.h
View File

@ -38,6 +38,7 @@
#ifndef _LINUXKPI_LINUX_SKBUFF_H
#define _LINUXKPI_LINUX_SKBUFF_H
#include <linux/kernel.h>
#include <linux/page.h>
#include <linux/dma-mapping.h>
#include <linux/netdev_features.h>
@ -84,7 +85,7 @@ enum sk_buff_pkt_type {
PACKET_OTHERHOST,
};
#define NET_SKB_PAD CACHE_LINE_SIZE /* ? */
#define NET_SKB_PAD max(CACHE_LINE_SIZE, 32)
struct sk_buff_head {
/* XXX TODO */
@ -168,6 +169,7 @@ struct sk_buff {
/* -------------------------------------------------------------------------- */
struct sk_buff *linuxkpi_alloc_skb(size_t, gfp_t);
struct sk_buff *linuxkpi_dev_alloc_skb(size_t, gfp_t);
void linuxkpi_kfree_skb(struct sk_buff *);
/* -------------------------------------------------------------------------- */
@ -187,7 +189,7 @@ __dev_alloc_skb(size_t len, gfp_t gfp)
{
struct sk_buff *skb;
skb = alloc_skb(len, gfp);
skb = linuxkpi_dev_alloc_skb(len, gfp);
SKB_IMPROVE();
SKB_TRACE(skb);
return (skb);
@ -198,7 +200,7 @@ dev_alloc_skb(size_t len)
{
struct sk_buff *skb;
skb = alloc_skb(len, GFP_NOWAIT);
skb = __dev_alloc_skb(len, GFP_NOWAIT);
SKB_IMPROVE();
SKB_TRACE(skb);
return (skb);

21
sys/compat/linuxkpi/common/src/linux_skbuff.c
View File

@ -80,7 +80,7 @@ linuxkpi_alloc_skb(size_t size, gfp_t gfp)
skb = malloc(len, M_LKPISKB, linux_check_m_flags(gfp) | M_ZERO);
if (skb == NULL)
return (skb);
skb->_alloc_len = size;
skb->_alloc_len = len;
skb->truesize = size;
skb->head = skb->data = skb->tail = (uint8_t *)(skb+1);
@ -90,7 +90,24 @@ linuxkpi_alloc_skb(size_t size, gfp_t gfp)
skb->shinfo = (struct skb_shared_info *)(skb->end);
SKB_TRACE_FMT(skb, "data %p size %zu", skb->data, size);
SKB_TRACE_FMT(skb, "data %p size %zu", (skb) ? skb->data : NULL, size);
return (skb);
}
struct sk_buff *
linuxkpi_dev_alloc_skb(size_t size, gfp_t gfp)
{
struct sk_buff *skb;
size_t len;
len = size + NET_SKB_PAD;
skb = linuxkpi_alloc_skb(len, gfp);
if (skb != NULL)
skb_reserve(skb, NET_SKB_PAD);
SKB_TRACE_FMT(skb, "data %p size %zu len %zu",
(skb) ? skb->data : NULL, size, len);
return (skb);
}