From b5be83e308f70e16c63c4e520ea7bb03ef57c46f Mon Sep 17 00:00:00 2001 From: Gregory Fong Date: Fri, 12 Dec 2014 16:54:48 -0800 Subject: mm: cma: align to physical address, not CMA region position The alignment in cma_alloc() was done w.r.t. the bitmap. This is a problem when, for example: - a device requires 16M (order 12) alignment - the CMA region is not 16 M aligned In such a case, can result with the CMA region starting at, say, 0x2f800000 but any allocation you make from there will be aligned from there. Requesting an allocation of 32 M with 16 M alignment will result in an allocation from 0x2f800000 to 0x31800000, which doesn't work very well if your strange device requires 16M alignment. Change to use bitmap_find_next_zero_area_off() to account for the difference in alignment at reserve-time and alloc-time. Signed-off-by: Gregory Fong Acked-by: Michal Nazarewicz Cc: Marek Szyprowski Cc: Joonsoo Kim Cc: Kukjin Kim Cc: Laurent Pinchart Cc: Laura Abbott Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/cma.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'mm/cma.c') diff --git a/mm/cma.c b/mm/cma.c index 8e9ec13d31db..5c96d7a3ba9c 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -63,6 +63,17 @@ static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) return (1UL << (align_order - cma->order_per_bit)) - 1; } +static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order) +{ + unsigned int alignment; + + if (align_order <= cma->order_per_bit) + return 0; + alignment = 1UL << (align_order - cma->order_per_bit); + return ALIGN(cma->base_pfn, alignment) - + (cma->base_pfn >> cma->order_per_bit); +} + static unsigned long cma_bitmap_maxno(struct cma *cma) { return cma->count >> cma->order_per_bit; @@ -340,7 +351,7 @@ err: */ struct page *cma_alloc(struct cma *cma, int count, unsigned int align) { - unsigned long mask, pfn, start = 0; + unsigned long mask, offset, pfn, start = 0; unsigned long bitmap_maxno, bitmap_no, bitmap_count; struct page *page = NULL; int ret; @@ -355,13 +366,15 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align) return NULL; mask = cma_bitmap_aligned_mask(cma, align); + offset = cma_bitmap_aligned_offset(cma, align); bitmap_maxno = cma_bitmap_maxno(cma); bitmap_count = cma_bitmap_pages_to_bits(cma, count); for (;;) { mutex_lock(&cma->lock); - bitmap_no = bitmap_find_next_zero_area(cma->bitmap, - bitmap_maxno, start, bitmap_count, mask); + bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, + bitmap_maxno, start, bitmap_count, mask, + offset); if (bitmap_no >= bitmap_maxno) { mutex_unlock(&cma->lock); break; -- cgit v1.2.2 From 620951e2745750de1482128615adc15b74ee37ed Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 12 Dec 2014 16:58:31 -0800 Subject: mm/cma: make kmemleak ignore CMA regions kmemleak will add allocations as objects to a pool. The memory allocated for each object in this pool is periodically searched for pointers to other allocated objects. This only works for memory that is mapped into the kernel's virtual address space, which happens not to be the case for most CMA regions. Furthermore, CMA regions are typically used to store data transferred to or from a device and therefore don't contain pointers to other objects. Without this, the kernel crashes on the first execution of the scan_gray_list() because it tries to access highmem. Perhaps a more appropriate fix would be to reject any object that can't map to a kernel virtual address? [akpm@linux-foundation.org: add comment] [akpm@linux-foundation.org: fix comment, per Catalin] [sfr@canb.auug.org.au: include linux/io.h for phys_to_virt()] Signed-off-by: Thierry Reding Cc: Michal Nazarewicz Cc: Marek Szyprowski Cc: Joonsoo Kim Cc: "Aneesh Kumar K.V" Cc: Catalin Marinas Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/cma.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'mm/cma.c') diff --git a/mm/cma.c b/mm/cma.c index 5c96d7a3ba9c..f8917629cbdd 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -33,6 +33,7 @@ #include #include #include +#include struct cma { unsigned long base_pfn; @@ -324,6 +325,11 @@ int __init cma_declare_contiguous(phys_addr_t base, } } + /* + * kmemleak scans/reads tracked objects for pointers to other + * objects but this address isn't mapped and accessible + */ + kmemleak_ignore(phys_to_virt(addr)); base = addr; } -- cgit v1.2.2