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Commit 130a1a9a authored by Guangguan Wang's avatar Guangguan Wang Committed by Greg Kroah-Hartman
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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 7c703e54 ("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: a3fe3d01 ("net/smc: introduce sg-logic for RMBs")
Signed-off-by: default avatarGuangguan Wang <guangguan.wang@linux.alibaba.com>
Co-developed-by: default avatarWen Gu <guwen@linux.alibaba.com>
Signed-off-by: default avatarWen Gu <guwen@linux.alibaba.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 33749ad4

net/smc/smc_core.c

+3 −2
Original line number Diff line number Diff line
@@ -691,7 +691,6 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini) 
 */

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)
@@ -701,9 +700,11 @@ 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;

}