qed: Limit msix vectors in kdump kernel to the minimum required count.

BugLink: https://bugs.launchpad.net/bugs/1790884

[ Upstream commit bb7858ba ]

Memory size is limited in the kdump kernel environment. Allocation of more
msix-vectors (or queues) consumes few tens of MBs of memory, which might
lead to the kdump kernel failure.
This patch adds changes to limit the number of MSI-X vectors in kdump
kernel to minimum required value (i.e., 2 per engine).

Fixes: fe56b9e6 ("qed: Add module with basic common support")
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/ethernet/qlogic/qed/qed_main.c

@@ -22,6 +22,7 @@
 #include <linux/etherdevice.h>
 #include <linux/vmalloc.h>
 #include <linux/qed/qed_if.h>
+#include <linux/crash_dump.h>
 
 #include "qed.h"
 #include "qed_sp.h"
@@ -636,6 +637,14 @@ static int qed_slowpath_setup_int(struct qed_dev *cdev,
 	/* We want a minimum of one slowpath and one fastpath vector per hwfn */
 	cdev->int_params.in.min_msix_cnt = cdev->num_hwfns * 2;
 
+	if (is_kdump_kernel()) {
+		DP_INFO(cdev,
+			"Kdump kernel: Limit the max number of requested MSI-X vectors to %hd\n",
+			cdev->int_params.in.min_msix_cnt);
+		cdev->int_params.in.num_vectors =
+			cdev->int_params.in.min_msix_cnt;
+	}
+
 	rc = qed_set_int_mode(cdev, false);
 	if (rc)  {
 		DP_ERR(cdev, "qed_slowpath_setup_int ERR\n");