sfc: Do not free an empty page_ring
authorMartin Habets <habetsm.xilinx@gmail.com>
Mon, 4 Apr 2022 10:48:51 +0000 (11:48 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Apr 2022 18:59:17 +0000 (20:59 +0200)
commitd1c87d36a655035f173288a12256fbc1de764538
treea5d473a240546400ca17fe579f103c05f53220ec
parent917eeb22002351bc111a9fb3fb4a3782c232c78c
sfc: Do not free an empty page_ring

[ Upstream commit 458f5d92df4807e2a7c803ed928369129996bf96 ]

When the page_ring is not used page_ptr_mask is 0.
Do not dereference page_ring[0] in this case.

Fixes: 2768935a4660 ("sfc: reuse pages to avoid DMA mapping/unmapping costs")
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Martin Habets <habetsm.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/ethernet/sfc/rx_common.c