-----Original Message-----
From: Tom Talpey <tom@talpey.com>
Sent: Friday, 21 October 2022 16:34
To: Long Li <longli@microsoft.com>; Bernard Metzler <redacted>;
KY Srinivasan [off-list ref]; Haiyang Zhang [off-list ref];
Stephen Hemminger [off-list ref]; Wei Liu [off-list ref];
Dexuan Cui [off-list ref]; David S. Miller [off-list ref];
Jakub Kicinski [off-list ref]; Paolo Abeni [off-list ref]; Jason
Gunthorpe [off-list ref]; Leon Romanovsky [off-list ref];
edumazet@google.com; shiraz.saleem@intel.com; Ajay Sharma
[off-list ref]
Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
kernel@vger.kernel.org; linux-rdma@vger.kernel.org
Subject: [EXTERNAL] Re: [Patch v8 12/12] RDMA/mana_ib: Add a driver for
Microsoft Azure Network Adapter

On 10/20/2022 4:42 PM, Long Li wrote:

quoted

quoted

[Bernard wrote...]

quoted

quoted

quoted

+	props->max_qp_wr = MAX_SEND_BUFFERS_PER_QUEUE;
+
+	/*
+	 * max_cqe could be potentially much bigger.
+	 * As this version of driver only support RAW QP, set it to the same
+	 * value as max_qp_wr
+	 */
+	props->max_cqe = MAX_SEND_BUFFERS_PER_QUEUE;
+
+	props->max_mr_size = MANA_IB_MAX_MR_SIZE;
+	props->max_mr = INT_MAX;

How the 24 bit wide MR keys can handle INT_MAX unique
MR's?

Not sure if I understand this correctly, lkey and rkey are u32 in ib_mr.

The upper 8 bits of an ib_mr remote token are reserved for use as a
rotating key, this allows a consumer to more safely reuse an ib_mr
without having to overallocate large region pools.

Tom.

Right, my point was that one cannot encode INT_MAX different MR 
identifiers into 32 - 8 = 24 bits.

Best,
Bernard.