[RFC 2/4] ARM: dma-mapping: IOMMU allocates pages from pool with GFP_ATOMIC
From: KyongHo Cho <hidden>
Date: 2012-08-22 12:47:03
Also in:
linux-mm
Hi. vzalloc() call in __iommu_alloc_buffer() also causes BUG() in atomic context. On Wed, Aug 22, 2012 at 7:20 PM, Hiroshi Doyu [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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,
quoted hunk ↗ jump to hunk
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,
quoted hunk ↗ jump to hunk
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;
+
for (i = 0; i < count; i++)
if (pages[i])
__free_pages(pages[i], 0);
--
1.7.5.4
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