[PATCH net-next v3 1/7] bnxt_en: Clear bp->total_irqs in bnxt_init_int_mode() during error

[Michael Chan <michael.chan@broadcom.com>]

During error, bnxt_init_int_mode() will free bp->irq_tbl but
bp->total_irqs retains the old value.  If a subsequent
reinitialization happens, bnxt_reserve_rings() may see that
bp->total_irqs does not match a new irqs_required.  It will then
try to adjust if dynamic MSI-X is supported and call
bnxt_change_msix().  It will then crash when dereferencing the NULL
bp->irq_tbl.

Fix it by clearing bp->total_irqs when freeing bp->irq_tbl.  Dynamic
MSI-X adjustments should only proceed if bp->irq_tbl is valid which
means that MSI-X has been initialized and can be adjusted.

Add a bp->irq_tbl_size to prevent OOB bp->irq_tbl[] array access in
case MSI-X capabilities change during re-init.  For dynamic MSI-X,
allocate the biggest bp->irq_tbl that is not clamped by CP/NQ rings
to allow dynamic MSI-X to grow to the max.

In the AER path, if MSI-X capabilities change, bnxt_reserve_rings()
will initialize MSI-X if BNXT_NEW_RM() is true.  Add a check in
bnxt_io_resume() to skip doing it again later.

Fixes: e68256c8a73c ("bnxt_en: Support dynamic MSIX")
Fixes: c2d20a3814d1 ("bnxt_en: delay pci_alloc_irq_vectors() in the AER path")
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
v3:
Added an additional Fixes tag.

v2:
https://lore.kernel.org/netdev/20260928041712.3467803-2-michael.chan@broadcom.com/
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 18 ++++++++++++++----
 drivers/net/ethernet/broadcom/bnxt/bnxt.h |  1 +
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index c1d3fcc7ae84..2bd2c039ce43 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11510,6 +11510,12 @@ static int bnxt_change_msix(struct bnxt *bp, int total)
 	struct msi_map map;
 	int i;
 
+	if (!bp->irq_tbl)
+		return 0;
+
+	if (total > bp->irq_tbl_size)
+		return bp->total_irqs;
+
 	/* add MSIX to the end if needed */
 	for (i = bp->total_irqs; i < total; i++) {
 		map = pci_msix_alloc_irq_at(bp->pdev, i, NULL);
@@ -11652,12 +11658,13 @@ static int bnxt_init_int_mode(struct bnxt *bp)
 
 	tbl_size = total_vecs;
 	if (pci_msix_can_alloc_dyn(bp->pdev))
-		tbl_size = max;
+		tbl_size = bp->hw_resc.max_irqs;
 	bp->irq_tbl = kzalloc_objs(*bp->irq_tbl, tbl_size);
 	if (!bp->irq_tbl) {
 		rc = -ENOMEM;
 		goto msix_setup_exit;
 	}
+	bp->irq_tbl_size = tbl_size;
 
 	for (i = 0; i < total_vecs; i++)
 		bp->irq_tbl[i].vector = pci_irq_vector(bp->pdev, i);
@@ -11680,6 +11687,8 @@ static int bnxt_init_int_mode(struct bnxt *bp)
 	netdev_err(bp->dev, "bnxt_init_int_mode err: %x\n", rc);
 	kfree(bp->irq_tbl);
 	bp->irq_tbl = NULL;
+	bp->total_irqs = 0;
+	bp->irq_tbl_size = 0;
 	pci_free_irq_vectors(bp->pdev);
 	return rc;
 }
@@ -11690,6 +11699,7 @@ static void bnxt_clear_int_mode(struct bnxt *bp)
 
 	kfree(bp->irq_tbl);
 	bp->irq_tbl = NULL;
+	bp->irq_tbl_size = 0;
 }
 
 int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
@@ -11716,7 +11726,7 @@ int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
 
 	if (irq_re_init && BNXT_NEW_RM(bp) && irqs_required != bp->total_irqs) {
 		irq_change = true;
-		if (!pci_msix_can_alloc_dyn(bp->pdev)) {
+		if (!pci_msix_can_alloc_dyn(bp->pdev) || !bp->irq_tbl) {
 			bnxt_ulp_irq_stop(bp);
 			bnxt_clear_int_mode(bp);
 			irq_cleared = true;
@@ -15080,7 +15090,7 @@ int bnxt_check_rings(struct bnxt *bp, int tx, int rx, bool sh, int tcs,
 			hwr.cp += bnxt_get_ulp_msix_num(bp);
 			hwr.cp = min_t(int, hwr.cp, bnxt_get_max_func_irqs(bp));
 		}
-		if (hwr.cp > bp->total_irqs) {
+		if (bp->irq_tbl && hwr.cp > bp->total_irqs) {
 			int total_msix = bnxt_change_msix(bp, hwr.cp);
 
 			if (total_msix < hwr.cp) {
@@ -17743,7 +17753,7 @@ static void bnxt_io_resume(struct pci_dev *pdev)
 			err = bnxt_open(netdev);
 		} else {
 			err = bnxt_reserve_rings(bp, true);
-			if (!err)
+			if (!err && !bp->irq_tbl)
 				err = bnxt_init_int_mode(bp);
 		}
 	}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 41d05efd6307..75428a585577 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -2489,6 +2489,7 @@ struct bnxt {
 	 */
 	unsigned long		*ring_affinity_set;
 	int			max_irqs;
+	int			irq_tbl_size;
 	int			total_irqs;
 	int			ulp_num_msix_want;
 	u8			mac_addr[ETH_ALEN];
-- 
2.51.0