Netdev Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH net] ibmvnic: Unmap DMA address of TX descriptor buffers after use
@ 2019-08-14 19:57 Thomas Falcon
  2019-08-18 20:58 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Thomas Falcon @ 2019-08-14 19:57 UTC (permalink / raw)
  To: netdev; +Cc: Thomas Falcon

There's no need to wait until a completion is received to unmap
TX descriptor buffers that have been passed to the hypervisor.
Instead unmap it when the hypervisor call has completed. This patch
avoids the possibility that a buffer will not be unmapped because
a TX completion is lost or mishandled.

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Tested-by: Devesh K. Singh <devesh_singh@in.ibm.com>
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 81a05ea38237..07efa2b40003 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1568,6 +1568,8 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		lpar_rc = send_subcrq_indirect(adapter, handle_array[queue_num],
 					       (u64)tx_buff->indir_dma,
 					       (u64)num_entries);
+		dma_unmap_single(dev, tx_buff->indir_dma,
+				 sizeof(tx_buff->indir_arr), DMA_TO_DEVICE);
 	} else {
 		tx_buff->num_entries = num_entries;
 		lpar_rc = send_subcrq(adapter, handle_array[queue_num],
@@ -2788,7 +2790,6 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 	union sub_crq *next;
 	int index;
 	int i, j;
-	u8 *first;
 
 restart_loop:
 	while (pending_scrq(adapter, scrq)) {
@@ -2818,14 +2819,6 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 
 				txbuff->data_dma[j] = 0;
 			}
-			/* if sub_crq was sent indirectly */
-			first = &txbuff->indir_arr[0].generic.first;
-			if (*first == IBMVNIC_CRQ_CMD) {
-				dma_unmap_single(dev, txbuff->indir_dma,
-						 sizeof(txbuff->indir_arr),
-						 DMA_TO_DEVICE);
-				*first = 0;
-			}
 
 			if (txbuff->last_frag) {
 				dev_kfree_skb_any(txbuff->skb);
-- 
2.16.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH net] ibmvnic: Unmap DMA address of TX descriptor buffers after use
  2019-08-14 19:57 [PATCH net] ibmvnic: Unmap DMA address of TX descriptor buffers after use Thomas Falcon
@ 2019-08-18 20:58 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-08-18 20:58 UTC (permalink / raw)
  To: tlfalcon; +Cc: netdev

From: Thomas Falcon <tlfalcon@linux.ibm.com>
Date: Wed, 14 Aug 2019 14:57:05 -0500

> There's no need to wait until a completion is received to unmap
> TX descriptor buffers that have been passed to the hypervisor.
> Instead unmap it when the hypervisor call has completed. This patch
> avoids the possibility that a buffer will not be unmapped because
> a TX completion is lost or mishandled.
> 
> Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
> Tested-by: Devesh K. Singh <devesh_singh@in.ibm.com>
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>

Applied.

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, back to index

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-14 19:57 [PATCH net] ibmvnic: Unmap DMA address of TX descriptor buffers after use Thomas Falcon
2019-08-18 20:58 ` David Miller

Netdev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/netdev/0 netdev/git/0.git
	git clone --mirror https://lore.kernel.org/netdev/1 netdev/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 netdev netdev/ https://lore.kernel.org/netdev \
		netdev@vger.kernel.org netdev@archiver.kernel.org
	public-inbox-index netdev


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.netdev


AGPL code for this site: git clone https://public-inbox.org/ public-inbox