On 1 September 2011 21:19, S, Venkatraman [off-list ref] wrote:

On Mon, Aug 29, 2011 at 3:38 AM, Per Forlin [off-list ref] wrote:

quoted

Reported by Russell King:
------------
mmcblk0: error -84 transferring data, sector 149201, nr 64,
cmd response 0x900, card status 0xb00
mmcblk0: retrying using single block read

WARNING: at /home/rmk/git/linux-2.6-rmk/lib/dma-debug.c:811 check_unmap
omap_hsmmc omap_hsmmc.0: DMA-API: device driver tries to free DMA memory
it has not allocated [device address=0x0000000080933000] [size=20480 bytes]
-------------

In case of an error dma_unmap() is issued in omap_hsmmc_dma_cleanup()
and then again in omap_hsmmc_post_req(). Resolve this by clearing the
host_cookie to indicate there is no DMA mapped memory to unmap.

Signed-off-by: Per Forlin <redacted>
---
Bug fix on 3.1-rc3

?drivers/mmc/host/omap_hsmmc.c | ? ?7 +++++--
?1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 21e4a79..31d9817 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c

@@ -1011,6 +1011,7 @@ static void omap_hsmmc_dma_cleanup(struct omap_hsmmc_host *host, int errno)

? ? ? ? ? ? ? ? ? ? ? ?host->data->sg_len,
? ? ? ? ? ? ? ? ? ? ? ?omap_hsmmc_get_dma_dir(host, host->data));
? ? ? ? ? ? ? ?omap_free_dma(dma_ch);
+ ? ? ? ? ? ? ? host->data->host_cookie = 0;
? ? ? ?}
? ? ? ?host->data = NULL;
?}

@@ -1576,8 +1577,10 @@ static void omap_hsmmc_post_req(struct mmc_host *mmc, struct mmc_request *mrq,

? ? ? ?struct mmc_data *data = mrq->data;

? ? ? ?if (host->use_dma) {
- ? ? ? ? ? ? ? dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
- ? ? ? ? ? ? ? ? ? ? ? ? ? ?omap_hsmmc_get_dma_dir(host, data));
+ ? ? ? ? ? ? ? if (data->host_cookie)
+ ? ? ? ? ? ? ? ? ? ? ? dma_unmap_sg(mmc_dev(host->mmc), data->sg,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?data->sg_len,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?omap_hsmmc_get_dma_dir(host, data));
? ? ? ? ? ? ? ?data->host_cookie = 0;
? ? ? ?}
?}
--
1.7.4.1

I just posted a patch [1] which just consolidates all unmapping to
just post_req.
This would obviously prevent double unmapping, and keeps all the related
dma operations at a single place. Let me know if that works better.

I'm in favour of such patch. My patch only tries to do the minimal bug fix.
I have been out of office the last 10 days or so. I'll look at your
patch later today.

Thanks,
Per