2013-05-18 02:51:51

by jonghwan Choi

Subject: [PATCH 3.9-table] NTB: Correctly handle receive buffers of the minimal size

From: Jon Mason <[email protected]>

This patch looks like it should be in the 3.9-stable tree, should we apply
it?

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

From: "Jon Mason <[email protected]>"

commit c9d534c8cbaedbb522a1d2cb037c6c394f610317 upstream

The ring logic of the NTB receive buffer/transmit memory window requires
there to be at least 2 payload sized allotments. For the minimal size
case, split the buffer into two and set the transport_mtu to the
appropriate size.

Cc: <[email protected]> # 3.9.x: ad3e2751: ntb: off by one
Cc: <[email protected]> # 3.9.x: cc0f868d: NTB: fix pointer math
Cc: <[email protected]> # 3.9.x: 113fc505: NTB: Handle 64bit BAR
Cc: <[email protected]> # 3.9.x: b77b2637: NTB: Link toggle memory
Cc: <[email protected]> # 3.9.x: 90f9e934: NTB: reset tx_index on
Signed-off-by: Jon Mason <[email protected]>
Signed-off-by: Jonghwan Choi <[email protected]>
---
drivers/ntb/ntb_transport.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 0828124..a288a26 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -490,11 +490,12 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
rx_size -= sizeof(struct ntb_rx_info);

qp->rx_buff = qp->remote_rx_info + 1;
- qp->rx_max_frame = min(transport_mtu, rx_size);
+ /* Due to housekeeping, there must be atleast 2 buffs */
+ qp->rx_max_frame = min(transport_mtu, rx_size / 2);
qp->rx_max_entry = rx_size / qp->rx_max_frame;
qp->rx_index = 0;

- qp->remote_rx_info->entry = qp->rx_max_entry;
+ qp->remote_rx_info->entry = qp->rx_max_entry - 1;

/* setup the hdr offsets with 0's */
for (i = 0; i < qp->rx_max_entry; i++) {
@@ -818,7 +819,8 @@ static void ntb_transport_init_queue(struct ntb_transport *nt,
tx_size -= sizeof(struct ntb_rx_info);

qp->tx_mw = qp->rx_info + 1;
- qp->tx_max_frame = min(transport_mtu, tx_size);
+ /* Due to housekeeping, there must be atleast 2 buffs */
+ qp->tx_max_frame = min(transport_mtu, tx_size / 2);
qp->tx_max_entry = tx_size / qp->tx_max_frame;

if (nt->debugfs_dir) {
--
1.8.1.2

2013-05-18 14:48:39

by Jon Mason

Subject: Re: [PATCH 3.9-table] NTB: Correctly handle receive buffers of the minimal size

On Sat, May 18, 2013 at 11:49:39AM +0900, Jonghwan Choi wrote:
> From: Jon Mason <[email protected]>
>
> This patch looks like it should be in the 3.9-stable tree, should we apply
> it?

Yes, thanks.

>
> ------------------
>
> From: "Jon Mason <[email protected]>"
>
> commit c9d534c8cbaedbb522a1d2cb037c6c394f610317 upstream
>
> The ring logic of the NTB receive buffer/transmit memory window requires
> there to be at least 2 payload sized allotments. For the minimal size
> case, split the buffer into two and set the transport_mtu to the
> appropriate size.
>
> Cc: <[email protected]> # 3.9.x: ad3e2751: ntb: off by one
> Cc: <[email protected]> # 3.9.x: cc0f868d: NTB: fix pointer math
> Cc: <[email protected]> # 3.9.x: 113fc505: NTB: Handle 64bit BAR
> Cc: <[email protected]> # 3.9.x: b77b2637: NTB: Link toggle memory
> Cc: <[email protected]> # 3.9.x: 90f9e934: NTB: reset tx_index on
> Signed-off-by: Jon Mason <[email protected]>
> Signed-off-by: Jonghwan Choi <[email protected]>
> ---
> drivers/ntb/ntb_transport.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
> index 0828124..a288a26 100644
> --- a/drivers/ntb/ntb_transport.c
> +++ b/drivers/ntb/ntb_transport.c
> @@ -490,11 +490,12 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
> rx_size -= sizeof(struct ntb_rx_info);
>
> qp->rx_buff = qp->remote_rx_info + 1;
> - qp->rx_max_frame = min(transport_mtu, rx_size);
> + /* Due to housekeeping, there must be atleast 2 buffs */
> + qp->rx_max_frame = min(transport_mtu, rx_size / 2);
> qp->rx_max_entry = rx_size / qp->rx_max_frame;
> qp->rx_index = 0;
>
> - qp->remote_rx_info->entry = qp->rx_max_entry;
> + qp->remote_rx_info->entry = qp->rx_max_entry - 1;
>
> /* setup the hdr offsets with 0's */
> for (i = 0; i < qp->rx_max_entry; i++) {
> @@ -818,7 +819,8 @@ static void ntb_transport_init_queue(struct ntb_transport *nt,
> tx_size -= sizeof(struct ntb_rx_info);
>
> qp->tx_mw = qp->rx_info + 1;
> - qp->tx_max_frame = min(transport_mtu, tx_size);
> + /* Due to housekeeping, there must be atleast 2 buffs */
> + qp->tx_max_frame = min(transport_mtu, tx_size / 2);
> qp->tx_max_entry = tx_size / qp->tx_max_frame;
>
> if (nt->debugfs_dir) {
> --
> 1.8.1.2
>