mac80211: Fix ieee80211_amsdu_aggregate frag_tail bug

stable inclusion
from stable-5.10.71
commit 3748871e1215834a5671849162afbcc4328f7f96
bugzilla: 182981 https://gitee.com/openeuler/kernel/issues/I4I3KD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3748871e1215834a5671849162afbcc4328f7f96



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[ Upstream commit fe94bac6 ]

In ieee80211_amsdu_aggregate() set a pointer frag_tail point to the
end of skb_shinfo(head)->frag_list, and use it to bind other skb in
the end of this function. But when execute ieee80211_amsdu_aggregate()
->ieee80211_amsdu_realloc_pad()->pskb_expand_head(), the address of
skb_shinfo(head)->frag_list will be changed. However, the
ieee80211_amsdu_aggregate() not update frag_tail after call
pskb_expand_head(). That will cause the second skb can't bind to the
head skb appropriately.So we update the address of frag_tail to fix it.

Fixes: 6e0456b5 ("mac80211: add A-MSDU tx support")
Signed-off-by: Chih-Kang Chang <gary.chang@realtek.com>
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/20210830073240.12736-1-pkshih@realtek.com


[reword comment]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>