net/smc: do not call dma sync for unmapped memory

The dma related ...sync_sg... functions check the link state before the
dma function is actually called. But the check in smc_link_usable()
allows links in ACTIVATING state which are not yet mapped to dma memory.
Under high load it may happen that the sync_sg functions are called for
such a link which results in an debug output like
   DMA-API: mlx5_core 0002:00:00.0: device driver tries to sync
   DMA memory it has not allocated [device address=0x0000000103370000]
   [size=65536 bytes]
To fix that introduce a helper to check for the link state ACTIVE and
use it where appropriate. And move the link state update to ACTIVATING
to the end of smcr_link_init() when most initial setup is done.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: d854fcbfaeda ("net/smc: add new link state and related helpers")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index c3ff512fd891..1c4d5439d0ff 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -349,6 +349,11 @@ static inline bool smc_link_usable(struct smc_link *lnk)
 	return true;
 }
 
+static inline bool smc_link_active(struct smc_link *lnk)
+{
+	return lnk->state == SMC_LNK_ACTIVE;
+}
+
 struct smc_sock;
 struct smc_clc_msg_accept_confirm;
 struct smc_clc_msg_local;