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net: hns3: fix reuse conflict of the rx page

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In the current rx page reuse handling process, the rx page buffer may
have conflict between driver and stack in high-pressure scenario.

To fix this problem, we need to check whether the page is only owned
by driver at the begin and at the end of a page to make sure there is
no reuse conflict between driver and stack when desc_cb->page_offset
is rollbacked to zero or increased.

Fixes: fa7711b888 ("net: hns3: optimize the rx page reuse handling process")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yunsheng Lin 2021-06-18 20:09:45 +08:00 committed by David S. Miller
parent cb5a82d2b9
commit 961045004b
1 changed files with 19 additions and 7 deletions
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26
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
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@ -3537,21 +3537,33 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i,
int size = le16_to_cpu(desc->rx.size);
u32 truesize = hns3_buf_size(ring);
u32 frag_size = size - pull_len;
bool reused;
/* Avoid re-using remote or pfmem page */
if (unlikely(!dev_page_is_reusable(desc_cb->priv)))
goto out;
/* Stack is not using and current page_offset is non-zero, we can
* reuse from the zero offset.
reused = hns3_can_reuse_page(desc_cb);
/* Rx page can be reused when:
* 1. Rx page is only owned by the driver when page_offset
* is zero, which means 0 @ truesize will be used by
* stack after skb_add_rx_frag() is called, and the rest
* of rx page can be reused by driver.
* Or
* 2. Rx page is only owned by the driver when page_offset
* is non-zero, which means page_offset @ truesize will
* be used by stack after skb_add_rx_frag() is called,
* and 0 @ truesize can be reused by driver.
*/
if (desc_cb->page_offset && hns3_can_reuse_page(desc_cb)) {
desc_cb->page_offset = 0;
desc_cb->reuse_flag = 1;
} else if (desc_cb->page_offset + truesize * 2 <=
hns3_page_size(ring)) {
if ((!desc_cb->page_offset && reused) ||
((desc_cb->page_offset + truesize + truesize) <=
hns3_page_size(ring) && desc_cb->page_offset)) {
desc_cb->page_offset += truesize;
desc_cb->reuse_flag = 1;
} else if (desc_cb->page_offset && reused) {
desc_cb->page_offset = 0;
desc_cb->reuse_flag = 1;
} else if (frag_size <= ring->rx_copybreak) {
void *frag = napi_alloc_frag(frag_size);