net: atlantic: fix aq_vec index out of range error

The final update statement of the for loop exceeds the array range, the
dereference of self->aq_vec[i] is not checked and then leads to the
index out of range error.
Also fixed this kind of coding style in other for loop.

[   97.937604] UBSAN: array-index-out-of-bounds in drivers/net/ethernet/aquantia/atlantic/aq_nic.c:1404:48
[   97.937607] index 8 is out of range for type 'aq_vec_s *[8]'
[   97.937608] CPU: 38 PID: 3767 Comm: kworker/u256:18 Not tainted 5.19.0+ #2
[   97.937610] Hardware name: Dell Inc. Precision 7865 Tower/, BIOS 1.0.0 06/12/2022
[   97.937611] Workqueue: events_unbound async_run_entry_fn
[   97.937616] Call Trace:
[   97.937617]  <TASK>
[   97.937619]  dump_stack_lvl+0x49/0x63
[   97.937624]  dump_stack+0x10/0x16
[   97.937626]  ubsan_epilogue+0x9/0x3f
[   97.937627]  __ubsan_handle_out_of_bounds.cold+0x44/0x49
[   97.937629]  ? __scm_send+0x348/0x440
[   97.937632]  ? aq_vec_stop+0x72/0x80 [atlantic]
[   97.937639]  aq_nic_stop+0x1b6/0x1c0 [atlantic]
[   97.937644]  aq_suspend_common+0x88/0x90 [atlantic]
[   97.937648]  aq_pm_suspend_poweroff+0xe/0x20 [atlantic]
[   97.937653]  pci_pm_suspend+0x7e/0x1a0
[   97.937655]  ? pci_pm_suspend_noirq+0x2b0/0x2b0
[   97.937657]  dpm_run_callback+0x54/0x190
[   97.937660]  __device_suspend+0x14c/0x4d0
[   97.937661]  async_suspend+0x23/0x70
[   97.937663]  async_run_entry_fn+0x33/0x120
[   97.937664]  process_one_work+0x21f/0x3f0
[   97.937666]  worker_thread+0x4a/0x3c0
[   97.937668]  ? process_one_work+0x3f0/0x3f0
[   97.937669]  kthread+0xf0/0x120
[   97.937671]  ? kthread_complete_and_exit+0x20/0x20
[   97.937672]  ret_from_fork+0x22/0x30
[   97.937676]  </TASK>

v2. fixed "warning: variable 'aq_vec' set but not used"

v3. simplified a for loop

Fixes: 97bde5c ("net: ethernet: aquantia: Support for NIC-specific code")
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Acked-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Link: https://lore.kernel.org/r/20220808081845.42005-1-acelan.kao@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: acelan

drivers/net/ethernet/aquantia/atlantic/aq_nic.c

@@ -265,12 +265,10 @@ static void aq_nic_service_timer_cb(struct timer_list *t)
 static void aq_nic_polling_timer_cb(struct timer_list *t)
 {
 	struct aq_nic_s *self = from_timer(self, t, polling_timer);
-	struct aq_vec_s *aq_vec = NULL;
 	unsigned int i = 0U;
 
-	for (i = 0U, aq_vec = self->aq_vec[0];
-		self->aq_vecs > i; ++i, aq_vec = self->aq_vec[i])
-		aq_vec_isr(i, (void *)aq_vec);
+	for (i = 0U; self->aq_vecs > i; ++i)
+		aq_vec_isr(i, (void *)self->aq_vec[i]);
 
 	mod_timer(&self->polling_timer, jiffies +
 		  AQ_CFG_POLLING_TIMER_INTERVAL);
@@ -1014,7 +1012,6 @@ int aq_nic_get_regs_count(struct aq_nic_s *self)
 
 u64 *aq_nic_get_stats(struct aq_nic_s *self, u64 *data)
 {
-	struct aq_vec_s *aq_vec = NULL;
 	struct aq_stats_s *stats;
 	unsigned int count = 0U;
 	unsigned int i = 0U;
@@ -1064,11 +1061,11 @@ u64 *aq_nic_get_stats(struct aq_nic_s *self, u64 *data)
 	data += i;
 
 	for (tc = 0U; tc < self->aq_nic_cfg.tcs; tc++) {
-		for (i = 0U, aq_vec = self->aq_vec[0];
-		     aq_vec && self->aq_vecs > i;
-		     ++i, aq_vec = self->aq_vec[i]) {
+		for (i = 0U; self->aq_vecs > i; ++i) {
+			if (!self->aq_vec[i])
+				break;
 			data += count;
-			count = aq_vec_get_sw_stats(aq_vec, tc, data);
+			count = aq_vec_get_sw_stats(self->aq_vec[i], tc, data);
 		}
 	}
 
@@ -1382,7 +1379,6 @@ int aq_nic_set_loopback(struct aq_nic_s *self)
 
 int aq_nic_stop(struct aq_nic_s *self)
 {
-	struct aq_vec_s *aq_vec = NULL;
 	unsigned int i = 0U;
 
 	netif_tx_disable(self->ndev);
@@ -1400,9 +1396,8 @@ int aq_nic_stop(struct aq_nic_s *self)
 
 	aq_ptp_irq_free(self);
 
-	for (i = 0U, aq_vec = self->aq_vec[0];
-		self->aq_vecs > i; ++i, aq_vec = self->aq_vec[i])
-		aq_vec_stop(aq_vec);
+	for (i = 0U; self->aq_vecs > i; ++i)
+		aq_vec_stop(self->aq_vec[i]);
 
 	aq_ptp_ring_stop(self);