This is a note to let you know that I've just added the patch titled
net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-smc-set-rmb-s-sg_max_single_alloc-limitation-onl.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 81b9238ed050092d22bd302c65412674ab8066ac
Author: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx>
Date: Mon Jun 3 11:00:18 2024 +0800
net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined
[ Upstream commit 3ac14b9dfbd345e891d48d89f6c2fa519848f0f4 ]
SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that
will be allocated in one piece of scatterlist. When the entries of
scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From
commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"),
we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify
whether sg chain is supported. So, SMC-R's rmb buffer should be limited
by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is
defined.
Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs")
Signed-off-by: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx>
Co-developed-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 691c1d9c4c560..6c19cc805abc1 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -666,7 +666,6 @@ int smc_conn_create(struct smc_sock *smc, bool is_smcd, int srv_first_contact,
*/
static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
{
- const unsigned int max_scat = SG_MAX_SINGLE_ALLOC * PAGE_SIZE;
u8 compressed;
if (size <= SMC_BUF_MIN_SIZE)
@@ -676,9 +675,11 @@ static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
compressed = min_t(u8, ilog2(size) + 1,
is_smcd ? SMCD_DMBE_SIZES : SMCR_RMBE_SIZES);
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
if (!is_smcd && is_rmb)
/* RMBs are backed by & limited to max size of scatterlists */
- compressed = min_t(u8, compressed, ilog2(max_scat >> 14));
+ compressed = min_t(u8, compressed, ilog2((SG_MAX_SINGLE_ALLOC * PAGE_SIZE) >> 14));
+#endif
return compressed;
}
