[PATCH 2/4] MMC: atmel-mci: prevent kernel oops while removing card

Nicolas Ferre
2010-04-27T13:20:45Z

The removing of an SD card in certain circumstances can lead to a kernel oops
if we do not make sure that the "data" field of the host structure is valid.
This patch adds a test in atmci_dma_cleanup() function and also calls
atmci_stop_dma() before throwing away the reference to data.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/mmc/host/atmel-mci.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 321e0bf..12572e5 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -569,9 +569,10 @@ static void atmci_dma_cleanup(struct atmel_mci *host)
{
struct mmc_data *data = host->data;

- dma_unmap_sg(&host->pdev->dev, data->sg, data->sg_len,
- ((data->flags & MMC_DATA_WRITE)
- ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
+ if (data)
+ dma_unmap_sg(&host->pdev->dev, data->sg, data->sg_len,
+ ((data->flags & MMC_DATA_WRITE)
+ ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
}

static void atmci_stop_dma(struct atmel_mci *host)
@@ -1113,8 +1114,8 @@ static void atmci_command_complete(struct atmel_mci *host,
"command error: status=0x%08x\n", status);

if (cmd->data) {
- host->data = NULL;
atmci_stop_dma(host);
+ host->data = NULL;
mci_writel(host, IDR, MCI_NOTBUSY
| MCI_TXRDY | MCI_RXRDY
| ATMCI_DATA_ERROR_FLAGS);
--
1.5.6.5