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Subject[PATCH 4.4 43/78] i40e: Do not enable NAPI on q_vectors that have no rings
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Duyck <alexander.h.duyck@intel.com>


[ Upstream commit 13a8cd191a2b470cfd435b3b57dbd21aa65ff78c ]

When testing the epoll w/ busy poll code I found that I could get into a
state where the i40e driver had q_vectors w/ active NAPI that had no rings.
This was resulting in a divide by zero error. To correct it I am updating
the driver code so that we only support NAPI on q_vectors that have 1 or
more rings allocated to them.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/intel/i40e/i40e_main.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -4201,8 +4201,12 @@ static void i40e_napi_enable_all(struct
if (!vsi->netdev)
return;

- for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++)
- napi_enable(&vsi->q_vectors[q_idx]->napi);
+ for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) {
+ struct i40e_q_vector *q_vector = vsi->q_vectors[q_idx];
+
+ if (q_vector->rx.ring || q_vector->tx.ring)
+ napi_enable(&q_vector->napi);
+ }
}

/**
@@ -4216,8 +4220,12 @@ static void i40e_napi_disable_all(struct
if (!vsi->netdev)
return;

- for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++)
- napi_disable(&vsi->q_vectors[q_idx]->napi);
+ for (q_idx = 0; q_idx < vsi->num_q_vectors; q_idx++) {
+ struct i40e_q_vector *q_vector = vsi->q_vectors[q_idx];
+
+ if (q_vector->rx.ring || q_vector->tx.ring)
+ napi_disable(&q_vector->napi);
+ }
}

/**

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