Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote @ Wed, 22 Aug 2012 14:29:47 +0200:
> Hello,
>
> On Wednesday, August 22, 2012 12:20 PM Hiroshi Doyu wrote:
>
> > Makes use of the same atomic pool from DMA, and skips kernel page
> > mapping which can involves sleep'able operation at allocating a kernel
> > page table.
> >
> > Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
> > ---
> > arch/arm/mm/dma-mapping.c | 22 ++++++++++++++++++----
> > 1 files changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > index aec0c06..9260107 100644
> > --- a/arch/arm/mm/dma-mapping.c
> > +++ b/arch/arm/mm/dma-mapping.c
> > @@ -1028,7 +1028,6 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t
> > size,
> > struct page **pages;
> > int count = size >> PAGE_SHIFT;
> > int array_size = count * sizeof(struct page *);
> > - int err;
> >
> > if (array_size <= PAGE_SIZE)
> > pages = kzalloc(array_size, gfp);
> > @@ -1037,9 +1036,20 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t
> > size,
> > if (!pages)
> > return NULL;
> >
> > - err = __alloc_fill_pages(&pages, count, gfp);
> > - if (err)
> > - goto error
> > + if (gfp & GFP_ATOMIC) {
> > + struct page *page;
> > + int i;
> > + void *addr = __alloc_from_pool(size, &page);
> > + if (!addr)
> > + goto err_out;
> > +
> > + for (i = 0; i < count; i++)
> > + pages[i] = page + i;
> > + } else {
> > + int err = __alloc_fill_pages(&pages, count, gfp);
> > + if (err)
> > + goto error;
> > + }
> >
> > return pages;
> > error:
> > @@ -1055,6 +1065,10 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
> > size_t s
> > int count = size >> PAGE_SHIFT;
> > int array_size = count * sizeof(struct page *);
> > int i;
> > +
> > + if (__free_from_pool(page_address(pages[0]), size))
> > + return 0;
>
> You leak memory here. pages array should be also freed.
Right, I'll fix as below:
Modified arch/arm/mm/dma-mapping.c
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 47c4978..4656c0f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1121,11 +1121,12 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t s
int i;
if (__free_from_pool(page_address(pages[0]), size))
- return 0;
+ goto out;
for (i = 0; i < count; i++)
if (pages[i])
__free_pages(pages[i], 0);
+out:
if (array_size <= PAGE_SIZE)
kfree(pages);
else
--
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