nvmet-tcp: use kvcalloc for commands array

Replace kcalloc with kvcalloc for allocation of the commands
array. Each command structure is 712 bytes. The array typically
exceeds a single page, and grows much larger with high queue depths
(e.g., commands >182KB).

kvcalloc automatically falls back to vmalloc for large or fragmented
allocations, improving reliability. In our case, this memory is not
aimed for DMA operations and could be safely allocated by kvcalloc.
Using virtually contiguous memory helps to avoid allocation failures
and out-of-memory conditions common with kcalloc on large pools.

Signed-off-by: Israel Rukshin <israelr@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: israelru

drivers/nvme/target/tcp.c

@@ -1484,7 +1484,7 @@ static int nvmet_tcp_alloc_cmds(struct nvmet_tcp_queue *queue)
 	struct nvmet_tcp_cmd *cmds;
 	int i, ret = -EINVAL, nr_cmds = queue->nr_cmds;
 
-	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_tcp_cmd), GFP_KERNEL);
+	cmds = kvcalloc(nr_cmds, sizeof(struct nvmet_tcp_cmd), GFP_KERNEL);
 	if (!cmds)
 		goto out;
 
@@ -1500,7 +1500,7 @@ static int nvmet_tcp_alloc_cmds(struct nvmet_tcp_queue *queue)
 out_free:
 	while (--i >= 0)
 		nvmet_tcp_free_cmd(cmds + i);
-	kfree(cmds);
+	kvfree(cmds);
 out:
 	return ret;
 }
@@ -1514,7 +1514,7 @@ static void nvmet_tcp_free_cmds(struct nvmet_tcp_queue *queue)
 		nvmet_tcp_free_cmd(cmds + i);
 
 	nvmet_tcp_free_cmd(&queue->connect);
-	kfree(cmds);
+	kvfree(cmds);
 }
 
 static void nvmet_tcp_restore_socket_callbacks(struct nvmet_tcp_queue *queue)