Pull request: sfc 2013-02-26

Pull request: sfc 2013-02-26

[Ben Hutchings]

The following changes since commit eb970ff07c15f13eb474f643fd165ebe3e4e24b2:

  usbnet: smsc95xx: rename FEATURE_AUTOSUSPEND (2013-02-25 15:49:52 -0500)

are available in the git repository at:
  git://git.kernel.org/pub/scm/linux/kernel/git/bwh/sfc.git sfc-3.9

Some fixes that should go into 3.9:

1. Fix packet corruption when using non-coherent RX DMA buffers.
2. Fix occasional watchdog misfiring when changing MTU or ring size.

These are longstanding bugs and should be fixed in stable as well, but
I'd like to review other recent fixes first and send a separate request
for stable inclusion.

Ben.

Ben Hutchings (3):
      sfc: Properly sync RX DMA buffer when it is not the last in the page
      sfc: Fix efx_rx_buf_offset() in the presence of swiotlb
      sfc: Detach net device when stopping queues for reconfiguration

 drivers/net/ethernet/sfc/efx.c        |   16 ++++++++++++----
 drivers/net/ethernet/sfc/net_driver.h |    4 +++-
 drivers/net/ethernet/sfc/rx.c         |   25 +++++++++++++++----------
 3 files changed, 30 insertions(+), 15 deletions(-)

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

[PATCH net 1/3] sfc: Properly sync RX DMA buffer when it is not the last in the page

[Ben Hutchings]

We may currently allocate two RX DMA buffers to a page, and only unmap
the page when the second is completed.  We do not sync the first RX
buffer to be completed; this can result in packet loss or corruption
if the last RX buffer completed in a NAPI poll is the first in a page
and is not DMA-coherent.  (In the middle of a NAPI poll, we will
handle the following RX completion and unmap the page *before* looking
at the content of the first buffer.)

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
 drivers/net/ethernet/sfc/rx.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index d780a0d..a575491 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -236,7 +236,8 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
 }
 
 static void efx_unmap_rx_buffer(struct efx_nic *efx,
-				struct efx_rx_buffer *rx_buf)
+				struct efx_rx_buffer *rx_buf,
+				unsigned int used_len)
 {
 	if ((rx_buf->flags & EFX_RX_BUF_PAGE) && rx_buf->u.page) {
 		struct efx_rx_page_state *state;
@@ -247,6 +248,10 @@ static void efx_unmap_rx_buffer(struct efx_nic *efx,
 				       state->dma_addr,
 				       efx_rx_buf_size(efx),
 				       DMA_FROM_DEVICE);
+		} else if (used_len) {
+			dma_sync_single_for_cpu(&efx->pci_dev->dev,
+						rx_buf->dma_addr, used_len,
+						DMA_FROM_DEVICE);
 		}
 	} else if (!(rx_buf->flags & EFX_RX_BUF_PAGE) && rx_buf->u.skb) {
 		dma_unmap_single(&efx->pci_dev->dev, rx_buf->dma_addr,
@@ -269,7 +274,7 @@ static void efx_free_rx_buffer(struct efx_nic *efx,
 static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
 			       struct efx_rx_buffer *rx_buf)
 {
-	efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
+	efx_unmap_rx_buffer(rx_queue->efx, rx_buf, 0);
 	efx_free_rx_buffer(rx_queue->efx, rx_buf);
 }
 
@@ -535,10 +540,10 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
 		goto out;
 	}
 
-	/* Release card resources - assumes all RX buffers consumed in-order
-	 * per RX queue
+	/* Release and/or sync DMA mapping - assumes all RX buffers
+	 * consumed in-order per RX queue
 	 */
-	efx_unmap_rx_buffer(efx, rx_buf);
+	efx_unmap_rx_buffer(efx, rx_buf, len);
 
 	/* Prefetch nice and early so data will (hopefully) be in cache by
 	 * the time we look at it.
-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

[PATCH net 2/3] sfc: Fix efx_rx_buf_offset() in the presence of swiotlb

[Ben Hutchings]

We assume that the mapping between DMA and virtual addresses is done
on whole pages, so we can find the page offset of an RX buffer using
the lower bits of the DMA address.  However, swiotlb maps in units of
2K, breaking this assumption.

Add an explicit page_offset field to struct efx_rx_buffer.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
 drivers/net/ethernet/sfc/net_driver.h |    4 +++-
 drivers/net/ethernet/sfc/rx.c         |   10 +++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 2d756c1..0a90abd 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -210,6 +210,7 @@ struct efx_tx_queue {
  *	Will be %NULL if the buffer slot is currently free.
  * @page: The associated page buffer. Valif iff @flags & %EFX_RX_BUF_PAGE.
  *	Will be %NULL if the buffer slot is currently free.
+ * @page_offset: Offset within page. Valid iff @flags & %EFX_RX_BUF_PAGE.
  * @len: Buffer length, in bytes.
  * @flags: Flags for buffer and packet state.
  */
@@ -219,7 +220,8 @@ struct efx_rx_buffer {
 		struct sk_buff *skb;
 		struct page *page;
 	} u;
-	unsigned int len;
+	u16 page_offset;
+	u16 len;
 	u16 flags;
 };
 #define EFX_RX_BUF_PAGE		0x0001
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index a575491..879ff58 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -90,11 +90,7 @@ static unsigned int rx_refill_threshold;
 static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx,
 					     struct efx_rx_buffer *buf)
 {
-	/* Offset is always within one page, so we don't need to consider
-	 * the page order.
-	 */
-	return ((unsigned int) buf->dma_addr & (PAGE_SIZE - 1)) +
-		efx->type->rx_buffer_hash_size;
+	return buf->page_offset + efx->type->rx_buffer_hash_size;
 }
 static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
 {
@@ -187,6 +183,7 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
 	struct efx_nic *efx = rx_queue->efx;
 	struct efx_rx_buffer *rx_buf;
 	struct page *page;
+	unsigned int page_offset;
 	struct efx_rx_page_state *state;
 	dma_addr_t dma_addr;
 	unsigned index, count;
@@ -211,12 +208,14 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
 		state->dma_addr = dma_addr;
 
 		dma_addr += sizeof(struct efx_rx_page_state);
+		page_offset = sizeof(struct efx_rx_page_state);
 
 	split:
 		index = rx_queue->added_count & rx_queue->ptr_mask;
 		rx_buf = efx_rx_buffer(rx_queue, index);
 		rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
 		rx_buf->u.page = page;
+		rx_buf->page_offset = page_offset;
 		rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
 		rx_buf->flags = EFX_RX_BUF_PAGE;
 		++rx_queue->added_count;
@@ -227,6 +226,7 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
 			/* Use the second half of the page */
 			get_page(page);
 			dma_addr += (PAGE_SIZE >> 1);
+			page_offset += (PAGE_SIZE >> 1);
 			++count;
 			goto split;
 		}
-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

[PATCH net 3/3] sfc: Detach net device when stopping queues for reconfiguration

[Ben Hutchings]

We must only ever stop TX queues when they are full or the net device
is not 'ready' so far as the net core, and specifically the watchdog,
is concerned.  Otherwise, the watchdog may fire *immediately* if no
packets have been added to the queue in the last 5 seconds.

The device is ready if all the following are true:

(a) It has a qdisc
(b) It is marked present
(c) It is running
(d) The link is reported up

(a) and (c) are normally true, and must not be changed by a driver.
(d) is under our control, but fake link changes may disturb userland.
This leaves (b).  We already mark the device absent during reset
and self-test, but we need to do the same during MTU changes and ring
reallocation.  We don't need to do this when the device is brought
down because then (c) is already false.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
 drivers/net/ethernet/sfc/efx.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index bf57b3c..0bc0099 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -779,6 +779,7 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
 						tx_queue->txd.entries);
 	}
 
+	efx_device_detach_sync(efx);
 	efx_stop_all(efx);
 	efx_stop_interrupts(efx, true);
 
@@ -832,6 +833,7 @@ out:
 
 	efx_start_interrupts(efx, true);
 	efx_start_all(efx);
+	netif_device_attach(efx->net_dev);
 	return rc;
 
 rollback:
@@ -1641,8 +1643,12 @@ static void efx_stop_all(struct efx_nic *efx)
 	/* Flush efx_mac_work(), refill_workqueue, monitor_work */
 	efx_flush_all(efx);
 
-	/* Stop the kernel transmit interface late, so the watchdog
-	 * timer isn't ticking over the flush */
+	/* Stop the kernel transmit interface.  This is only valid if
+	 * the device is stopped or detached; otherwise the watchdog
+	 * may fire immediately.
+	 */
+	WARN_ON(netif_running(efx->net_dev) &&
+		netif_device_present(efx->net_dev));
 	netif_tx_disable(efx->net_dev);
 
 	efx_stop_datapath(efx);
@@ -1963,16 +1969,18 @@ static int efx_change_mtu(struct net_device *net_dev, int new_mtu)
 	if (new_mtu > EFX_MAX_MTU)
 		return -EINVAL;
 
-	efx_stop_all(efx);
-
 	netif_dbg(efx, drv, efx->net_dev, "changing MTU to %d\n", new_mtu);
 
+	efx_device_detach_sync(efx);
+	efx_stop_all(efx);
+
 	mutex_lock(&efx->mac_lock);
 	net_dev->mtu = new_mtu;
 	efx->type->reconfigure_mac(efx);
 	mutex_unlock(&efx->mac_lock);
 
 	efx_start_all(efx);
+	netif_device_attach(efx->net_dev);
 	return 0;
 }
 
-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: Pull request: sfc 2013-02-26

[David Miller]

From: Ben Hutchings <bhutchings@solarflare.com>
Date: Tue, 26 Feb 2013 19:09:23 +0000

> The following changes since commit eb970ff07c15f13eb474f643fd165ebe3e4e24b2:
> 
>   usbnet: smsc95xx: rename FEATURE_AUTOSUSPEND (2013-02-25 15:49:52 -0500)
> 
> are available in the git repository at:
>   git://git.kernel.org/pub/scm/linux/kernel/git/bwh/sfc.git sfc-3.9
> 
> Some fixes that should go into 3.9:
> 
> 1. Fix packet corruption when using non-coherent RX DMA buffers.
> 2. Fix occasional watchdog misfiring when changing MTU or ring size.
> 
> These are longstanding bugs and should be fixed in stable as well, but
> I'd like to review other recent fixes first and send a separate request
> for stable inclusion.

Pulled, thanks Ben.