* [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling
@ 2022-09-28 17:21 Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 1/4] staging: vt6655: remove redundant if condition Nam Cao
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Nam Cao @ 2022-09-28 17:21 UTC (permalink / raw)
To: forest, gregkh, dan.carpenter
Cc: namcaov, philipp.g.hortmann, linux-kernel, linux-staging
This driver does not handle allocation failure when receiving data very
well. This patchset implements better handling in the case of allocation
failure.
Also do some necessary clean-up to implement this.
v2:
- squash 3 commits that were doing a single thing
- add new commit which removes a redundant assignment
- take device_init_rx_desc() out of unnecessary else condition.
- remove return statement at the end of void function
- add a missing rd = rd->next statement in device_rx_srv(): because
we already drop the current buffer, we should move on to the next
buffer in the ring where new data will be written to.
Nam Cao (4):
staging: vt6655: remove redundant if condition
staging: vt6655: change vnt_receive_frame return type to void
staging: vt6655: remove redundant assignment
staging: vt6655: implement allocation failure handling
drivers/staging/vt6655/device_main.c | 40 +++++++++++++++++-----------
drivers/staging/vt6655/dpc.c | 8 +++---
drivers/staging/vt6655/dpc.h | 2 +-
3 files changed, 28 insertions(+), 22 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [RFC PATCH v2 1/4] staging: vt6655: remove redundant if condition
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
@ 2022-09-28 17:21 ` Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 2/4] staging: vt6655: change vnt_receive_frame return type to void Nam Cao
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Nam Cao @ 2022-09-28 17:21 UTC (permalink / raw)
To: forest, gregkh, dan.carpenter
Cc: namcaov, philipp.g.hortmann, linux-kernel, linux-staging
The function vnt_receive_frame always returns true, so checking its
return value is redundant. Remove it.
Signed-off-by: Nam Cao <namcaov@gmail.com>
---
drivers/staging/vt6655/device_main.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index 56c3cf3ba53d..21d10d9fde47 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -832,12 +832,12 @@ static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
if (!rd->rd_info->skb)
break;
- if (vnt_receive_frame(priv, rd)) {
- if (!device_alloc_rx_buf(priv, rd)) {
- dev_err(&priv->pcid->dev,
- "can not allocate rx buf\n");
- break;
- }
+ vnt_receive_frame(priv, rd);
+
+ if (!device_alloc_rx_buf(priv, rd)) {
+ dev_err(&priv->pcid->dev,
+ "can not allocate rx buf\n");
+ break;
}
rd->rd0.owner = OWNED_BY_NIC;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [RFC PATCH v2 2/4] staging: vt6655: change vnt_receive_frame return type to void
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 1/4] staging: vt6655: remove redundant if condition Nam Cao
@ 2022-09-28 17:21 ` Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 3/4] staging: vt6655: remove redundant assignment Nam Cao
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Nam Cao @ 2022-09-28 17:21 UTC (permalink / raw)
To: forest, gregkh, dan.carpenter
Cc: namcaov, philipp.g.hortmann, linux-kernel, linux-staging
The function vnt_receive_frame's returned value is not used anywhere.
Furthermore, it always return true. Change its return type to void.
Signed-off-by: Nam Cao <namcaov@gmail.com>
---
drivers/staging/vt6655/dpc.c | 8 +++-----
drivers/staging/vt6655/dpc.h | 2 +-
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/vt6655/dpc.c b/drivers/staging/vt6655/dpc.c
index c6ed3537f439..3bf60039fa9a 100644
--- a/drivers/staging/vt6655/dpc.c
+++ b/drivers/staging/vt6655/dpc.c
@@ -115,7 +115,7 @@ static bool vnt_rx_data(struct vnt_private *priv, struct sk_buff *skb,
return true;
}
-bool vnt_receive_frame(struct vnt_private *priv, struct vnt_rx_desc *curr_rd)
+void vnt_receive_frame(struct vnt_private *priv, struct vnt_rx_desc *curr_rd)
{
struct vnt_rd_info *rd_info = curr_rd->rd_info;
struct sk_buff *skb;
@@ -133,13 +133,11 @@ bool vnt_receive_frame(struct vnt_private *priv, struct vnt_rx_desc *curr_rd)
/* Frame Size error drop this packet.*/
dev_dbg(&priv->pcid->dev, "Wrong frame size %d\n", frame_size);
dev_kfree_skb_irq(skb);
- return true;
+ return;
}
if (vnt_rx_data(priv, skb, frame_size))
- return true;
+ return;
dev_kfree_skb_irq(skb);
-
- return true;
}
diff --git a/drivers/staging/vt6655/dpc.h b/drivers/staging/vt6655/dpc.h
index 40364c0ab7f6..f67c1ef23171 100644
--- a/drivers/staging/vt6655/dpc.h
+++ b/drivers/staging/vt6655/dpc.h
@@ -16,6 +16,6 @@
#include "device.h"
-bool vnt_receive_frame(struct vnt_private *priv, struct vnt_rx_desc *curr_rd);
+void vnt_receive_frame(struct vnt_private *priv, struct vnt_rx_desc *curr_rd);
#endif /* __RXTX_H__ */
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [RFC PATCH v2 3/4] staging: vt6655: remove redundant assignment
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 1/4] staging: vt6655: remove redundant if condition Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 2/4] staging: vt6655: change vnt_receive_frame return type to void Nam Cao
@ 2022-09-28 17:21 ` Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 4/4] staging: vt6655: implement allocation failure handling Nam Cao
2022-09-29 20:30 ` [RFC PATCH v2 0/4] staging: vt6655: Implement " Philipp Hortmann
4 siblings, 0 replies; 6+ messages in thread
From: Nam Cao @ 2022-09-28 17:21 UTC (permalink / raw)
To: forest, gregkh, dan.carpenter
Cc: namcaov, philipp.g.hortmann, linux-kernel, linux-staging
In function device_rx_srv, the assignment rd->rd0.owner = OWNED_BY_NIC
is redundant because this is already done in device_alloc_rx_buf() which
is called right above. Remove it.
Signed-off-by: Nam Cao <namcaov@gmail.com>
---
drivers/staging/vt6655/device_main.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index 21d10d9fde47..c8cae6df7f51 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -839,7 +839,6 @@ static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
"can not allocate rx buf\n");
break;
}
- rd->rd0.owner = OWNED_BY_NIC;
}
priv->pCurrRD[idx] = rd;
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [RFC PATCH v2 4/4] staging: vt6655: implement allocation failure handling
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
` (2 preceding siblings ...)
2022-09-28 17:21 ` [RFC PATCH v2 3/4] staging: vt6655: remove redundant assignment Nam Cao
@ 2022-09-28 17:21 ` Nam Cao
2022-09-29 20:30 ` [RFC PATCH v2 0/4] staging: vt6655: Implement " Philipp Hortmann
4 siblings, 0 replies; 6+ messages in thread
From: Nam Cao @ 2022-09-28 17:21 UTC (permalink / raw)
To: forest, gregkh, dan.carpenter
Cc: namcaov, philipp.g.hortmann, linux-kernel, linux-staging
The function device_rx_srv does not handle allocation failure very well.
Currently, it performs these steps:
- Unmap DMA buffer and hand over the buffer to mac80211
- Allocate and dma-map new buffer
- If allocation fails, abort
The problem is that, it aborts while still marking the buffer as
OWNED_BY_HOST. So when this function is called again in the future, it
incorrectly perceives the same buffer as valid and dma-unmap and hand
over this buffer to mac80211 again.
Re-implement this function to do things in a different order:
- Allocate and dma-map new buffer
- If allocation fails, abort and give up the ownership of the
buffer (so that the device can re-use this buffer)
- If allocation does not fail: unmap dma buffer and hand over
the buffer to mac80211
Thus, when the driver cannot allocate new buffer, it simply discards the
received data and re-use the current buffer.
Also split device_alloc_rx_buf() into 2 parts: allocating new buffer and
initializing the buffer, so that we can read the old buffer in between.
Signed-off-by: Nam Cao <namcaov@gmail.com>
---
drivers/staging/vt6655/device_main.c | 33 ++++++++++++++++++----------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index c8cae6df7f51..cc952acd9825 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -132,7 +132,8 @@ static int device_init_td1_ring(struct vnt_private *priv);
static int device_rx_srv(struct vnt_private *priv, unsigned int idx);
static int device_tx_srv(struct vnt_private *priv, unsigned int idx);
-static bool device_alloc_rx_buf(struct vnt_private *, struct vnt_rx_desc *);
+static bool device_alloc_rx_buf(struct vnt_private *, struct vnt_rd_info *);
+static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd);
static void device_free_rx_buf(struct vnt_private *priv,
struct vnt_rx_desc *rd);
static void device_init_registers(struct vnt_private *priv);
@@ -611,12 +612,13 @@ static int device_init_rd0_ring(struct vnt_private *priv)
goto err_free_desc;
}
- if (!device_alloc_rx_buf(priv, desc)) {
+ if (!device_alloc_rx_buf(priv, desc->rd_info)) {
dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
ret = -ENOMEM;
goto err_free_rd;
}
+ device_init_rx_desc(priv, desc);
desc->next = &priv->aRD0Ring[(i + 1) % priv->opts.rx_descs0];
desc->next_desc = cpu_to_le32(curr + sizeof(struct vnt_rx_desc));
}
@@ -657,12 +659,13 @@ static int device_init_rd1_ring(struct vnt_private *priv)
goto err_free_desc;
}
- if (!device_alloc_rx_buf(priv, desc)) {
+ if (!device_alloc_rx_buf(priv, desc->rd_info)) {
dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
ret = -ENOMEM;
goto err_free_rd;
}
+ device_init_rx_desc(priv, desc);
desc->next = &priv->aRD1Ring[(i + 1) % priv->opts.rx_descs1];
desc->next_desc = cpu_to_le32(curr + sizeof(struct vnt_rx_desc));
}
@@ -821,6 +824,7 @@ static void device_free_td1_ring(struct vnt_private *priv)
static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
{
struct vnt_rx_desc *rd;
+ struct vnt_rd_info new_info;
int works = 0;
for (rd = priv->pCurrRD[idx];
@@ -832,13 +836,18 @@ static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
if (!rd->rd_info->skb)
break;
- vnt_receive_frame(priv, rd);
-
- if (!device_alloc_rx_buf(priv, rd)) {
+ if (!device_alloc_rx_buf(priv, &new_info)) {
dev_err(&priv->pcid->dev,
"can not allocate rx buf\n");
+ rd->rd0.owner = OWNED_BY_NIC;
+ rd = rd->next;
break;
}
+
+ vnt_receive_frame(priv, rd);
+
+ memcpy(rd->rd_info, &new_info, sizeof(new_info));
+ device_init_rx_desc(priv, rd);
}
priv->pCurrRD[idx] = rd;
@@ -847,10 +856,8 @@ static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
}
static bool device_alloc_rx_buf(struct vnt_private *priv,
- struct vnt_rx_desc *rd)
+ struct vnt_rd_info *rd_info)
{
- struct vnt_rd_info *rd_info = rd->rd_info;
-
rd_info->skb = dev_alloc_skb((int)priv->rx_buf_sz);
if (!rd_info->skb)
return false;
@@ -864,15 +871,17 @@ static bool device_alloc_rx_buf(struct vnt_private *priv,
rd_info->skb = NULL;
return false;
}
+ return true;
+}
+static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd)
+{
*((unsigned int *)&rd->rd0) = 0; /* FIX cast */
rd->rd0.res_count = cpu_to_le16(priv->rx_buf_sz);
rd->rd0.owner = OWNED_BY_NIC;
rd->rd1.req_count = cpu_to_le16(priv->rx_buf_sz);
- rd->buff_addr = cpu_to_le32(rd_info->skb_dma);
-
- return true;
+ rd->buff_addr = cpu_to_le32(rd->rd_info->skb_dma);
}
static void device_free_rx_buf(struct vnt_private *priv,
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
` (3 preceding siblings ...)
2022-09-28 17:21 ` [RFC PATCH v2 4/4] staging: vt6655: implement allocation failure handling Nam Cao
@ 2022-09-29 20:30 ` Philipp Hortmann
4 siblings, 0 replies; 6+ messages in thread
From: Philipp Hortmann @ 2022-09-29 20:30 UTC (permalink / raw)
To: Nam Cao, forest, gregkh, dan.carpenter; +Cc: linux-kernel, linux-staging
On 9/28/22 19:21, Nam Cao wrote:
> This driver does not handle allocation failure when receiving data very
> well. This patchset implements better handling in the case of allocation
> failure.
>
> Also do some necessary clean-up to implement this.
>
> v2:
> - squash 3 commits that were doing a single thing
> - add new commit which removes a redundant assignment
> - take device_init_rx_desc() out of unnecessary else condition.
> - remove return statement at the end of void function
> - add a missing rd = rd->next statement in device_rx_srv(): because
> we already drop the current buffer, we should move on to the next
> buffer in the ring where new data will be written to.
>
> Nam Cao (4):
> staging: vt6655: remove redundant if condition
> staging: vt6655: change vnt_receive_frame return type to void
> staging: vt6655: remove redundant assignment
> staging: vt6655: implement allocation failure handling
>
> drivers/staging/vt6655/device_main.c | 40 +++++++++++++++++-----------
> drivers/staging/vt6655/dpc.c | 8 +++---
> drivers/staging/vt6655/dpc.h | 2 +-
> 3 files changed, 28 insertions(+), 22 deletions(-)
>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-09-29 20:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-28 17:21 [RFC PATCH v2 0/4] staging: vt6655: Implement allocation failure handling Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 1/4] staging: vt6655: remove redundant if condition Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 2/4] staging: vt6655: change vnt_receive_frame return type to void Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 3/4] staging: vt6655: remove redundant assignment Nam Cao
2022-09-28 17:21 ` [RFC PATCH v2 4/4] staging: vt6655: implement allocation failure handling Nam Cao
2022-09-29 20:30 ` [RFC PATCH v2 0/4] staging: vt6655: Implement " Philipp Hortmann
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