RDMA/rxe: Prevent faulty rkey generation

If you create MRs more than 0x10000 times after loading the module,
responder starts to reply NAKs for RDMA/Atomic operations because of rkey
violation detected in check_rkey(). The root cause is that rkeys are
incremented each time a new MR is created and the value overflows into the
range reserved for MWs.

This commit also increases the value of RXE_MAX_MW that has been limited
unlike other parameters.

Fixes: 0994a1b ("RDMA/rxe: Bump up default maximum values used via uverbs")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daisuke Matsuda <[email protected]>
Tested-by: Li Zhijian <[email protected]>
Reviewed-by: Li Zhijian <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: ddmatsu

drivers/infiniband/sw/rxe/rxe_param.h

@@ -98,11 +98,11 @@ enum rxe_device_param {
 	RXE_MAX_SRQ			= DEFAULT_MAX_VALUE - RXE_MIN_SRQ_INDEX,
 
 	RXE_MIN_MR_INDEX		= 0x00000001,
-	RXE_MAX_MR_INDEX		= DEFAULT_MAX_VALUE,
-	RXE_MAX_MR			= DEFAULT_MAX_VALUE - RXE_MIN_MR_INDEX,
-	RXE_MIN_MW_INDEX		= 0x00010001,
-	RXE_MAX_MW_INDEX		= 0x00020000,
-	RXE_MAX_MW			= 0x00001000,
+	RXE_MAX_MR_INDEX		= DEFAULT_MAX_VALUE >> 1,
+	RXE_MAX_MR			= RXE_MAX_MR_INDEX - RXE_MIN_MR_INDEX,
+	RXE_MIN_MW_INDEX		= RXE_MAX_MR_INDEX + 1,
+	RXE_MAX_MW_INDEX		= DEFAULT_MAX_VALUE,
+	RXE_MAX_MW			= RXE_MAX_MW_INDEX - RXE_MIN_MW_INDEX,
 
 	RXE_MAX_PKT_PER_ACK		= 64,