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net: generalize sk_alloc_sg to work with scatterlist rings

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The current implementation of sk_alloc_sg expects scatterlist to always
start at entry 0 and complete at entry MAX_SKB_FRAGS.

Future patches will want to support starting at arbitrary offset into
scatterlist so add an additional sg_start parameters and then default
to the current values in TLS code paths.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
John Fastabend 2018-03-18 12:57:05 -07:00 committed by Daniel Borkmann
parent 312fc2b4c8
commit 8c05dbf04b
3 changed files with 19 additions and 14 deletions
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2
include/net/sock.h
View File

@ -2142,7 +2142,7 @@ static inline struct page_frag *sk_page_frag(struct sock *sk)
bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
int sk_alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
int *sg_num_elem, unsigned int *sg_size,
int sg_start, int *sg_curr, unsigned int *sg_size,
int first_coalesce);
/*

27
net/core/sock.c
View File

@ -2240,19 +2240,20 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
EXPORT_SYMBOL(sk_page_frag_refill);
int sk_alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
int *sg_num_elem, unsigned int *sg_size,
int sg_start, int *sg_curr_index, unsigned int *sg_curr_size,
int first_coalesce)
{
int sg_curr = *sg_curr_index, use = 0, rc = 0;
unsigned int size = *sg_curr_size;
struct page_frag *pfrag;
unsigned int size = *sg_size;
int num_elem = *sg_num_elem, use = 0, rc = 0;
struct scatterlist *sge;
unsigned int orig_offset;
len -= size;
pfrag = sk_page_frag(sk);
while (len > 0) {
unsigned int orig_offset;
if (!sk_page_frag_refill(sk, pfrag)) {
rc = -ENOMEM;
goto out;
@ -2270,17 +2271,21 @@ int sk_alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
orig_offset = pfrag->offset;
pfrag->offset += use;
sge = sg + num_elem - 1;
if (num_elem > first_coalesce && sg_page(sg) == pfrag->page &&
sge = sg + sg_curr - 1;
if (sg_curr > first_coalesce && sg_page(sg) == pfrag->page &&
sg->offset + sg->length == orig_offset) {
sg->length += use;
} else {
sge++;
sge = sg + sg_curr;
sg_unmark_end(sge);
sg_set_page(sge, pfrag->page, use, orig_offset);
get_page(pfrag->page);
++num_elem;
if (num_elem == MAX_SKB_FRAGS) {
sg_curr++;
if (sg_curr == MAX_SKB_FRAGS)
sg_curr = 0;
if (sg_curr == sg_start) {
rc = -ENOSPC;
break;
}
@ -2289,8 +2294,8 @@ int sk_alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
len -= use;
}
out:
*sg_size = size;
*sg_num_elem = num_elem;
*sg_curr_size = size;
*sg_curr_index = sg_curr;
return rc;
}
EXPORT_SYMBOL(sk_alloc_sg);

4
net/tls/tls_sw.c
View File

@ -94,7 +94,7 @@ static int alloc_encrypted_sg(struct sock *sk, int len)
int rc = 0;
rc = sk_alloc_sg(sk, len,
ctx->sg_encrypted_data,
ctx->sg_encrypted_data, 0,
&ctx->sg_encrypted_num_elem,
&ctx->sg_encrypted_size, 0);
@ -107,7 +107,7 @@ static int alloc_plaintext_sg(struct sock *sk, int len)
struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
int rc = 0;
rc = sk_alloc_sg(sk, len, ctx->sg_plaintext_data,
rc = sk_alloc_sg(sk, len, ctx->sg_plaintext_data, 0,
&ctx->sg_plaintext_num_elem, &ctx->sg_plaintext_size,
tls_ctx->pending_open_record_frags);