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net: splice: avoid high order page splitting

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splice() can handle pages of any order, but network code tries hard to
split them in PAGE_SIZE units. Not quite successfully anyway, as
__splice_segment() assumed poff < PAGE_SIZE. This is true for
the skb->data part, not necessarily for the fragments.

This patch removes this logic to give the pages as they are in the skb.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2013-01-05 21:31:18 +00:00 committed by David S. Miller
parent b74aa930ef
commit 82bda61956
1 changed files with 9 additions and 29 deletions
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38
net/core/skbuff.c
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@ -1706,20 +1706,6 @@ static bool spd_fill_page(struct splice_pipe_desc *spd,
return false;
}
static inline void __segment_seek(struct page **page, unsigned int *poff,
unsigned int *plen, unsigned int off)
{
unsigned long n;
*poff += off;
n = *poff / PAGE_SIZE;
if (n)
*page = nth_page(*page, n);
*poff = *poff % PAGE_SIZE;
*plen -= off;
}
static bool __splice_segment(struct page *page, unsigned int poff,
unsigned int plen, unsigned int *off,
unsigned int *len, struct sk_buff *skb,
@ -1727,6 +1713,8 @@ static bool __splice_segment(struct page *page, unsigned int poff,
struct sock *sk,
struct pipe_inode_info *pipe)
{
unsigned int flen;
if (!*len)
return true;
@ -1737,24 +1725,16 @@ static bool __splice_segment(struct page *page, unsigned int poff,
}
/* ignore any bits we already processed */
if (*off) {
__segment_seek(&page, &poff, &plen, *off);
*off = 0;
}
poff += *off;
plen -= *off;
*off = 0;
do {
unsigned int flen = min(*len, plen);
flen = min(*len, plen);
/* the linear region may spread across several pages */
flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
return true;
if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
return true;
__segment_seek(&page, &poff, &plen, flen);
*len -= flen;
} while (*len && plen);
*len -= flen;
return false;
}