2016-05-25 14:40:41

by Ashok Raj Nagarajan

Subject: [PATCH] ath10k: fix diag_read to collect data for larger memory

diag_read uses dma_alloc_coherent to allocate memory requested by the
caller. If this memory requested is larger, more than DIAG_TRANSFER_LIMIT
(2K), then it is likely that we may not get the requested memory and we
would fail.

To solve this, request dma_alloc_coherent for only DIAG_TRANSFER_LIMIT, and
reuse this buffer multiple times as needed to copy the data requested in
smaller chunks of size not more than DIAG_TRANSFER_LIMIT. Previously we
were reading into the caller's only after getting the complete requested
data.

Fixes: 68c03249f388 ('ath10k: convert pci_alloc_consistent() to dma_alloc_coherent()')
Signed-off-by: Ashok Raj Nagarajan <[email protected]>
---
drivers/net/wireless/ath/ath10k/pci.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 8133d7b..8663a3b 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -864,7 +864,7 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
int ret = 0;
u32 *buf;
- unsigned int completed_nbytes, orig_nbytes, remaining_bytes;
+ unsigned int completed_nbytes, alloc_nbytes, remaining_bytes;
struct ath10k_ce_pipe *ce_diag;
/* Host buffer address in CE space */
u32 ce_data;
@@ -882,9 +882,10 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
* 1) 4-byte alignment
* 2) Buffer in DMA-able space
*/
- orig_nbytes = nbytes;
+ alloc_nbytes = min_t(unsigned int, nbytes, DIAG_TRANSFER_LIMIT);
+
data_buf = (unsigned char *)dma_alloc_coherent(ar->dev,
- orig_nbytes,
+ alloc_nbytes,
&ce_data_base,
GFP_ATOMIC);

@@ -892,9 +893,9 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
ret = -ENOMEM;
goto done;
}
- memset(data_buf, 0, orig_nbytes);
+ memset(data_buf, 0, alloc_nbytes);

- remaining_bytes = orig_nbytes;
+ remaining_bytes = nbytes;
ce_data = ce_data_base;
while (remaining_bytes) {
nbytes = min_t(unsigned int, remaining_bytes,
@@ -954,19 +955,22 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
}

remaining_bytes -= nbytes;
+
+ if (ret) {
+ ath10k_warn(ar, "failed to read diag value at 0x%x: %d\n",
+ address, ret);
+ break;
+ }
+ memcpy(data, data_buf, nbytes);
+
address += nbytes;
- ce_data += nbytes;
+ data += nbytes;
}

done:
- if (ret == 0)
- memcpy(data, data_buf, orig_nbytes);
- else
- ath10k_warn(ar, "failed to read diag value at 0x%x: %d\n",
- address, ret);

if (data_buf)
- dma_free_coherent(ar->dev, orig_nbytes, data_buf,
+ dma_free_coherent(ar->dev, alloc_nbytes, data_buf,
ce_data_base);

spin_unlock_bh(&ar_pci->ce_lock);
--
1.9.1

2016-06-02 14:51:04

by Kalle Valo

Subject: Re: ath10k: fix diag_read to collect data for larger memory

Ashok Raj Nagarajan <[email protected]> wrote:
> diag_read uses dma_alloc_coherent to allocate memory requested by the
> caller. If this memory requested is larger, more than DIAG_TRANSFER_LIMIT
> (2K), then it is likely that we may not get the requested memory and we
> would fail.
>
> To solve this, request dma_alloc_coherent for only DIAG_TRANSFER_LIMIT, and
> reuse this buffer multiple times as needed to copy the data requested in
> smaller chunks of size not more than DIAG_TRANSFER_LIMIT. Previously we
> were reading into the caller's only after getting the complete requested
> data.
>
> Fixes: 68c03249f388 ('ath10k: convert pci_alloc_consistent() to dma_alloc_coherent()')
> Signed-off-by: Ashok Raj Nagarajan <[email protected]>

Thanks, 1 patch applied to ath.git:

1e56d5127d5c ath10k: fix diag_read to collect data for larger memory

--
Sent by pwcli
https://patchwork.kernel.org/patch/9135561/