diff options
| author | Huang Shijie <shijie8@gmail.com> | 2013-12-18 23:41:00 +0800 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2014-01-27 21:55:03 -0800 |
| commit | 0ff76a920e3558307567b45aa0a91fb914924bfc (patch) | |
| tree | de9fcf55103af0f753dda69599989c3b63758112 /drivers/mtd | |
| parent | 06f216c83c25adadc231469d51ab133afdfe110a (diff) | |
| download | linux-0ff76a920e3558307567b45aa0a91fb914924bfc.tar.bz2 | |
mtd: gpmi: add sanity check when mapping DMA for read_buf/write_buf
The buffer pointer passed from the upper layer may points to
a buffer in the stack or a buffer allocated by vmalloc, and etc..
This patch adds more sanity check to this buffer.
After this patch, if we meet a buffer which is allocated by vmalloc or
a buffer in the stack, we will use our own DMA buffer @data_buffer_dma
to do the DMA operations. If the buffer is not the cases above, we will
map it for DMA operations directly.
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c index d1d13d86b7e0..ca6369fe91ff 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c @@ -367,25 +367,28 @@ void prepare_data_dma(struct gpmi_nand_data *this, enum dma_data_direction dr) struct scatterlist *sgl = &this->data_sgl; int ret; - this->direct_dma_map_ok = true; - /* first try to map the upper buffer directly */ - sg_init_one(sgl, this->upper_buf, this->upper_len); - ret = dma_map_sg(this->dev, sgl, 1, dr); - if (ret == 0) { - /* We have to use our own DMA buffer. */ - sg_init_one(sgl, this->data_buffer_dma, PAGE_SIZE); - - if (dr == DMA_TO_DEVICE) - memcpy(this->data_buffer_dma, this->upper_buf, - this->upper_len); - + if (virt_addr_valid(this->upper_buf) && + !object_is_on_stack(this->upper_buf)) { + sg_init_one(sgl, this->upper_buf, this->upper_len); ret = dma_map_sg(this->dev, sgl, 1, dr); if (ret == 0) - dev_err(this->dev, "DMA mapping failed.\n"); + goto map_fail; - this->direct_dma_map_ok = false; + this->direct_dma_map_ok = true; + return; } + +map_fail: + /* We have to use our own DMA buffer. */ + sg_init_one(sgl, this->data_buffer_dma, this->upper_len); + + if (dr == DMA_TO_DEVICE) + memcpy(this->data_buffer_dma, this->upper_buf, this->upper_len); + + dma_map_sg(this->dev, sgl, 1, dr); + + this->direct_dma_map_ok = false; } /* This will be called after the DMA operation is finished. */ |