diff mbox series

[net,3/3] i40e: fix vf may be used uninitialized in this function warning

Message ID 20240326162358.1224145-4-anthony.l.nguyen@intel.com (mailing list archive)
State Accepted
Commit f37c4eac99c258111d414d31b740437e1925b8e8
Delegated to: Netdev Maintainers
Headers show
Series Intel Wired LAN Driver Updates 2024-03-26 (i40e) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 944 this patch: 944
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 955 this patch: 955
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 955 this patch: 955
netdev/checkpatch warning WARNING: line length of 86 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-03-27--15-00 (tests: 952)

Commit Message

Tony Nguyen March 26, 2024, 4:23 p.m. UTC 
From: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

To fix the regression introduced by commit 52424f974bc5, which causes
servers hang in very hard to reproduce conditions with resets races.
Using two sources for the information is the root cause.
In this function before the fix bumping v didn't mean bumping vf
pointer. But the code used this variables interchangeably, so stale vf
could point to different/not intended vf.

Remove redundant "v" variable and iterate via single VF pointer across
whole function instead to guarantee VF pointer validity.

Fixes: 52424f974bc5 ("i40e: Fix VF hang when reset is triggered on another VF")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 .../ethernet/intel/i40e/i40e_virtchnl_pf.c    | 34 +++++++++----------
 1 file changed, 16 insertions(+), 18 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index 83a34e98bdc7..4c13f78af675 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -1624,8 +1624,8 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 {
 	struct i40e_hw *hw = &pf->hw;
 	struct i40e_vf *vf;
-	int i, v;
 	u32 reg;
+	int i;
 
 	/* If we don't have any VFs, then there is nothing to reset */
 	if (!pf->num_alloc_vfs)
@@ -1636,11 +1636,10 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 		return false;
 
 	/* Begin reset on all VFs at once */
-	for (v = 0; v < pf->num_alloc_vfs; v++) {
-		vf = &pf->vf[v];
+	for (vf = &pf->vf[0]; vf < &pf->vf[pf->num_alloc_vfs]; ++vf) {
 		/* If VF is being reset no need to trigger reset again */
 		if (!test_bit(I40E_VF_STATE_RESETTING, &vf->vf_states))
-			i40e_trigger_vf_reset(&pf->vf[v], flr);
+			i40e_trigger_vf_reset(vf, flr);
 	}
 
 	/* HW requires some time to make sure it can flush the FIFO for a VF
@@ -1649,14 +1648,13 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 	 * the VFs using a simple iterator that increments once that VF has
 	 * finished resetting.
 	 */
-	for (i = 0, v = 0; i < 10 && v < pf->num_alloc_vfs; i++) {
+	for (i = 0, vf = &pf->vf[0]; i < 10 && vf < &pf->vf[pf->num_alloc_vfs]; ++i) {
 		usleep_range(10000, 20000);
 
 		/* Check each VF in sequence, beginning with the VF to fail
 		 * the previous check.
 		 */
-		while (v < pf->num_alloc_vfs) {
-			vf = &pf->vf[v];
+		while (vf < &pf->vf[pf->num_alloc_vfs]) {
 			if (!test_bit(I40E_VF_STATE_RESETTING, &vf->vf_states)) {
 				reg = rd32(hw, I40E_VPGEN_VFRSTAT(vf->vf_id));
 				if (!(reg & I40E_VPGEN_VFRSTAT_VFRD_MASK))
@@ -1666,7 +1664,7 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 			/* If the current VF has finished resetting, move on
 			 * to the next VF in sequence.
 			 */
-			v++;
+			++vf;
 		}
 	}
 
@@ -1676,39 +1674,39 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 	/* Display a warning if at least one VF didn't manage to reset in
 	 * time, but continue on with the operation.
 	 */
-	if (v < pf->num_alloc_vfs)
+	if (vf < &pf->vf[pf->num_alloc_vfs])
 		dev_err(&pf->pdev->dev, "VF reset check timeout on VF %d\n",
-			pf->vf[v].vf_id);
+			vf->vf_id);
 	usleep_range(10000, 20000);
 
 	/* Begin disabling all the rings associated with VFs, but do not wait
 	 * between each VF.
 	 */
-	for (v = 0; v < pf->num_alloc_vfs; v++) {
+	for (vf = &pf->vf[0]; vf < &pf->vf[pf->num_alloc_vfs]; ++vf) {
 		/* On initial reset, we don't have any queues to disable */
-		if (pf->vf[v].lan_vsi_idx == 0)
+		if (vf->lan_vsi_idx == 0)
 			continue;
 
 		/* If VF is reset in another thread just continue */
 		if (test_bit(I40E_VF_STATE_RESETTING, &vf->vf_states))
 			continue;
 
-		i40e_vsi_stop_rings_no_wait(pf->vsi[pf->vf[v].lan_vsi_idx]);
+		i40e_vsi_stop_rings_no_wait(pf->vsi[vf->lan_vsi_idx]);
 	}
 
 	/* Now that we've notified HW to disable all of the VF rings, wait
 	 * until they finish.
 	 */
-	for (v = 0; v < pf->num_alloc_vfs; v++) {
+	for (vf = &pf->vf[0]; vf < &pf->vf[pf->num_alloc_vfs]; ++vf) {
 		/* On initial reset, we don't have any queues to disable */
-		if (pf->vf[v].lan_vsi_idx == 0)
+		if (vf->lan_vsi_idx == 0)
 			continue;
 
 		/* If VF is reset in another thread just continue */
 		if (test_bit(I40E_VF_STATE_RESETTING, &vf->vf_states))
 			continue;
 
-		i40e_vsi_wait_queues_disabled(pf->vsi[pf->vf[v].lan_vsi_idx]);
+		i40e_vsi_wait_queues_disabled(pf->vsi[vf->lan_vsi_idx]);
 	}
 
 	/* Hw may need up to 50ms to finish disabling the RX queues. We
@@ -1717,12 +1715,12 @@  bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr)
 	mdelay(50);
 
 	/* Finish the reset on each VF */
-	for (v = 0; v < pf->num_alloc_vfs; v++) {
+	for (vf = &pf->vf[0]; vf < &pf->vf[pf->num_alloc_vfs]; ++vf) {
 		/* If VF is reset in another thread just continue */
 		if (test_bit(I40E_VF_STATE_RESETTING, &vf->vf_states))
 			continue;
 
-		i40e_cleanup_reset_vf(&pf->vf[v]);
+		i40e_cleanup_reset_vf(vf);
 	}
 
 	i40e_flush(hw);