From: Dany Madden <drt@linux•ibm.com>
To: Sukadev Bhattiprolu <sukadev@linux•ibm.com>
Cc: netdev@vger•kernel.org, Brian King <brking@linux•ibm.com>,
cforno12@linux•ibm.com, Rick Lindsley <ricklind@linux•ibm.com>
Subject: Re: [PATCH net-next 6/9] ibmvnic: Use bitmap for LTB map_ids
Date: Tue, 31 Aug 2021 18:33:52 -0700 [thread overview]
Message-ID: <7ca16990a95b30c2f6387e4b4cebda55@imap.linux.ibm.com> (raw)
In-Reply-To: <20210901000812.120968-7-sukadev@linux.ibm.com>
On 2021-08-31 17:08, Sukadev Bhattiprolu wrote:
> In a follow-on patch, we will reuse long term buffers when possible.
> When doing so we have to be careful to properly assign map ids. We
> can no longer assign them sequentially because a lower map id may be
> available and we could wrap at 255 and collide with an in-use map id.
>
> Instead, use a bitmap to track active map ids and to find a free map
> id.
> Don't need to take locks here since the map_id only changes during
> reset
> and at that time only the reset worker thread should be using the
> adapter.
>
> Noticed this when analyzing an error Dany Madden ran into with the
> patch set.
>
> Reported-by: Dany Madden <drt@linux•ibm.com>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux•ibm.com>
Reviewed-by: Dany Madden <drt@linux•ibm.com>
> ---
> drivers/net/ethernet/ibm/ibmvnic.c | 12 ++++++++----
> drivers/net/ethernet/ibm/ibmvnic.h | 3 ++-
> 2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.c
> b/drivers/net/ethernet/ibm/ibmvnic.c
> index 8894afdb3cb3..30153a8bb5ec 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -228,8 +228,9 @@ static int alloc_long_term_buff(struct
> ibmvnic_adapter *adapter,
> dev_err(dev, "Couldn't alloc long term buffer\n");
> return -ENOMEM;
> }
> - ltb->map_id = adapter->map_id;
> - adapter->map_id++;
> + ltb->map_id = find_first_zero_bit(adapter->map_ids,
> + MAX_MAP_ID);
> + bitmap_set(adapter->map_ids, ltb->map_id, 1);
>
> mutex_lock(&adapter->fw_lock);
> adapter->fw_done_rc = 0;
> @@ -284,6 +285,8 @@ static void free_long_term_buff(struct
> ibmvnic_adapter *adapter,
> dma_free_coherent(dev, ltb->size, ltb->buff, ltb->addr);
>
> ltb->buff = NULL;
> + /* mark this map_id free */
> + bitmap_clear(adapter->map_ids, ltb->map_id, 1);
> ltb->map_id = 0;
> }
>
> @@ -1231,8 +1234,6 @@ static int init_resources(struct ibmvnic_adapter
> *adapter)
> return rc;
> }
>
> - adapter->map_id = 1;
> -
> rc = init_napi(adapter);
> if (rc)
> return rc;
> @@ -5553,6 +5554,9 @@ static int ibmvnic_probe(struct vio_dev *dev,
> const struct vio_device_id *id)
> adapter->vdev = dev;
> adapter->netdev = netdev;
> adapter->login_pending = false;
> + memset(&adapter->map_ids, 0, sizeof(adapter->map_ids));
> + /* map_ids start at 1, so ensure map_id 0 is always "in-use" */
> + bitmap_set(adapter->map_ids, 0, 1);
>
> ether_addr_copy(adapter->mac_addr, mac_addr_p);
> ether_addr_copy(netdev->dev_addr, adapter->mac_addr);
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.h
> b/drivers/net/ethernet/ibm/ibmvnic.h
> index 5652566818fb..e97f1aa98c05 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.h
> +++ b/drivers/net/ethernet/ibm/ibmvnic.h
> @@ -979,7 +979,8 @@ struct ibmvnic_adapter {
> u64 opt_tx_entries_per_subcrq;
> u64 opt_rxba_entries_per_subcrq;
> __be64 tx_rx_desc_req;
> - u8 map_id;
> +#define MAX_MAP_ID 255
> + DECLARE_BITMAP(map_ids, MAX_MAP_ID);
> u32 num_active_rx_scrqs;
> u32 num_active_rx_pools;
> u32 num_active_rx_napi;
next prev parent reply other threads:[~2021-09-01 1:33 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 0:08 [PATCH net-next 0/9] ibmvnic: Reuse ltb, rx, tx pools Sukadev Bhattiprolu
2021-09-01 0:08 ` [PATCH net-next 1/9] ibmvnic: Consolidate code in replenish_rx_pool() Sukadev Bhattiprolu
2021-09-01 1:26 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 2/9] ibmvnic: Fix up some comments and messages Sukadev Bhattiprolu
2021-09-01 1:28 ` Dany Madden
2021-09-01 8:58 ` kernel test robot
2021-09-01 0:08 ` [PATCH net-next 3/9] ibmvnic: Use/rename local vars in init_rx_pools Sukadev Bhattiprolu
2021-09-01 1:28 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 4/9] ibmvnic: Use/rename local vars in init_tx_pools Sukadev Bhattiprolu
2021-09-01 1:30 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 5/9] ibmvnic: init_tx_pools move loop-invariant code out Sukadev Bhattiprolu
2021-09-01 1:32 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 6/9] ibmvnic: Use bitmap for LTB map_ids Sukadev Bhattiprolu
2021-09-01 1:33 ` Dany Madden [this message]
2021-09-01 0:08 ` [PATCH net-next 7/9] ibmvnic: Reuse LTB when possible Sukadev Bhattiprolu
2021-09-01 1:34 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 8/9] ibmvnic: Reuse rx pools " Sukadev Bhattiprolu
2021-09-01 1:35 ` Dany Madden
2021-09-01 0:08 ` [PATCH net-next 9/9] ibmvnic: Reuse tx " Sukadev Bhattiprolu
2021-09-01 1:36 ` Dany Madden
2021-09-01 1:21 ` [PATCH net-next 0/9] ibmvnic: Reuse ltb, rx, tx pools Rick Lindsley
2021-09-01 2:35 ` Jakub Kicinski
2021-09-01 18:07 ` Sukadev Bhattiprolu
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