diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2014-01-21 15:48:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-21 16:19:41 -0800 |
| commit | 0abdd7a81b7e3fd781d7fabcca49501852bba17e (patch) | |
| tree | 20ab3aa4b476ceaf6d3a824c842cd581445ded8b /mm/memory.c | |
| parent | 03d11a0e458d7008192585124e4c3313c2829046 (diff) | |
dma-debug: introduce debug_dma_assert_idle()
Record actively mapped pages and provide an api for asserting a given
page is dma inactive before execution proceeds. Placing
debug_dma_assert_idle() in cow_user_page() flagged the violation of the
dma-api in the NET_DMA implementation (see commit 77873803363c "net_dma:
mark broken").
The implementation includes the capability to count, in a limited way,
repeat mappings of the same page that occur without an intervening
unmap. This 'overlap' counter is limited to the few bits of tag space
in a radix tree. This mechanism is added to mitigate false negative
cases where, for example, a page is dma mapped twice and
debug_dma_assert_idle() is called after the page is un-mapped once.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index 6768ce9e57d..e9c550484ba 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -59,6 +59,7 @@ #include <linux/gfp.h> #include <linux/migrate.h> #include <linux/string.h> +#include <linux/dma-debug.h> #include <asm/io.h> #include <asm/pgalloc.h> @@ -2559,6 +2560,8 @@ static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) { + debug_dma_assert_idle(src); + /* * If the source page was a PFN mapping, we don't have * a "struct page" for it. We do a best-effort copy by |