> -----Original Message-----
> From: Jesper Dangaard Brouer [mailto:[email protected]]
> Sent: Friday, December 22, 2017 10:42 PM
> To: Daniel Borkmann <[email protected]>; Alexei Starovoitov
> <[email protected]>
> Cc: [email protected]; [email protected]; Jesper Dangaard Brouer
> <[email protected]>; Elior, Ariel <[email protected]>;
> [email protected]; [email protected]; Dept-Eng Everest Linux L2 <Dept-
> [email protected]>; [email protected]
> Subject: [bpf-next V2 PATCH 05/14] xdp/qede: setup xdp_rxq_info and intro
> xdp_rxq_info_is_reg
>
> The driver code qede_free_fp_array() depend on kfree() can be called with a
> NULL pointer. This stems from the qede_alloc_fp_array() function which either
> (kz)alloc memory for fp->txq or fp->rxq.
> This also simplifies error handling code in case of memory allocation
> failures,
> but xdp_rxq_info_unreg need to know the difference.
>
> Introduce xdp_rxq_info_is_reg() to handle if a memory allocation fails and
> detect this is the failure path by seeing that xdp_rxq_info was not registred
> yet,
> which first happens after successful alloaction in qede_init_fp().
>
> Driver hook points for xdp_rxq_info:
> * reg : qede_init_fp
> * unreg: qede_free_fp_array
>
> Tested on actual hardware with samples/bpf program.
>
> V2: Driver have no proper error path for failed XDP RX-queue info reg, as
> qede_init_fp() is a void function.
>
> Cc: [email protected]
> Cc: Ariel Elior <[email protected]>
> Signed-off-by: Jesper Dangaard Brouer <[email protected]>
> ---
> drivers/net/ethernet/qlogic/qede/qede.h | 2 ++
> drivers/net/ethernet/qlogic/qede/qede_fp.c | 1 +
> drivers/net/ethernet/qlogic/qede/qede_main.c | 10 ++++++++++
> include/net/xdp.h | 1 +
> net/core/xdp.c | 6 ++++++
> 5 files changed, 20 insertions(+)
>
> diff --git a/drivers/net/ethernet/qlogic/qede/qede.h
> b/drivers/net/ethernet/qlogic/qede/qede.h
> index a3a70ade411f..62f47736511b 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede.h
> +++ b/drivers/net/ethernet/qlogic/qede/qede.h
> @@ -40,6 +40,7 @@
> #include <linux/kernel.h>
> #include <linux/mutex.h>
> #include <linux/bpf.h>
> +#include <net/xdp.h>
> #include <linux/qed/qede_rdma.h>
> #include <linux/io.h>
> #ifdef CONFIG_RFS_ACCEL
> @@ -345,6 +346,7 @@ struct qede_rx_queue {
> u64 xdp_no_pass;
>
> void *handle;
> + struct xdp_rxq_info xdp_rxq;
> };
>
> union db_prod {
> diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c
> b/drivers/net/ethernet/qlogic/qede/qede_fp.c
> index 48ec4c56cddf..dafc079ab6b9 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
> +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c
> @@ -1006,6 +1006,7 @@ static bool qede_rx_xdp(struct qede_dev *edev,
> xdp.data = xdp.data_hard_start + *data_offset;
> xdp_set_data_meta_invalid(&xdp);
> xdp.data_end = xdp.data + *len;
> + xdp.rxq = &rxq->xdp_rxq;
>
> /* Queues always have a full reset currently, so for the time
> * being until there's atomic program replace just mark read diff --git
> a/drivers/net/ethernet/qlogic/qede/qede_main.c
> b/drivers/net/ethernet/qlogic/qede/qede_main.c
> index 57332b3e5e64..24160f1fd0e5 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede_main.c
> +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
> @@ -762,6 +762,12 @@ static void qede_free_fp_array(struct qede_dev *edev)
> fp = &edev->fp_array[i];
>
> kfree(fp->sb_info);
> + /* Handle mem alloc failure case where qede_init_fp
> + * didn't register xdp_rxq_info yet.
> + * Implicit only (fp->type & QEDE_FASTPATH_RX)
> + */
> + if (fp->rxq && xdp_rxq_info_is_reg(&fp->rxq->xdp_rxq))
> + xdp_rxq_info_unreg(&fp->rxq->xdp_rxq);
Isn't this sufficient just ?
If (fp->rxq)
xdp_rxq_info_unreg(&fp->rxq->xdp_rxq);
xdp_rxq_info_is_reg() API seems unnecessary to me, xdp_rxq_info_unreg() seems
to be taking care of the case
if it's not registered then WARN already, I think instead of adding these
checks in individual drivers, better handle it properly in xdp_rxq_info_unreg()
?
> kfree(fp->rxq);
> kfree(fp->xdp_tx);
> kfree(fp->txq);
> @@ -1498,6 +1504,10 @@ static void qede_init_fp(struct qede_dev *edev)
> else
> fp->rxq->data_direction =
> DMA_FROM_DEVICE;
> fp->rxq->dev = &edev->pdev->dev;
> +
> + /* Driver have no error path from here */
> + WARN_ON(xdp_rxq_info_reg(&fp->rxq->xdp_rxq, edev-
> >ndev,
> + fp->rxq->rxq_id) < 0);
> }
We will reach to this point only when fp->rxq and edev are valid
I don't think that xdp_rxq_info_reg() will fail ever in that case.
