staging/rdma/hfi1: Fix for module parameter rcvhdrcnt when it's 2097152

The driver crashes when loaded with parameter rcvhdrcnt=2097152.
The root cause was that rcvhdrcnt was initially a 32 bit variable
and its value was assigned to a 16 bit variable, truncating the
upper 16 bits. This patch prevents the user from passing a value
for rcvhdrcnt greater than 16352 (Maximum number for rcvhdrcnt).
Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/init.c

@@ -77,6 +77,7 @@
 #define HFI1_MIN_USER_CTXT_BUFCNT 7
 
 #define HFI1_MIN_HDRQ_EGRBUF_CNT 2
+#define HFI1_MAX_HDRQ_EGRBUF_CNT 16352
 #define HFI1_MIN_EAGER_BUFFER_SIZE (4 * 1024) /* 4KB */
 #define HFI1_MAX_EAGER_BUFFER_SIZE (256 * 1024) /* 256KB */
 
@@ -1355,6 +1356,13 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		ret = -EINVAL;
 		goto bail;
 	}
+	if (rcvhdrcnt > HFI1_MAX_HDRQ_EGRBUF_CNT) {
+		hfi1_early_err(&pdev->dev,
+			       "Receive header queue count cannot be greater than %u\n",
+			       HFI1_MAX_HDRQ_EGRBUF_CNT);
+		ret = -EINVAL;
+		goto bail;
+	}
 	/* use the encoding function as a sanitization check */
 	if (!encode_rcv_header_entry_size(hfi1_hdrq_entsize)) {
 		hfi1_early_err(&pdev->dev, "Invalid HdrQ Entry size %u\n",