| Message ID | 1345796945-21115-2-git-send-email-hdoyu@nvidia.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Aug 24, 2012 at 11:29:02AM +0300, Hiroshi Doyu wrote: > struct page **pages is necessary to align with non atomic path in > __iommu_get_pages(). atomic_pool() has the intialized **pages instead > of just *page. > > Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> > --- > arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- > 1 files changed, 13 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index 601da7a..b14ee64 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -296,7 +296,7 @@ struct dma_pool { > unsigned long *bitmap; > unsigned long nr_pages; > void *vaddr; > - struct page *page; > + struct page **pages; > }; > > static struct dma_pool atomic_pool = { > @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) > unsigned long nr_pages = pool->size >> PAGE_SHIFT; > unsigned long *bitmap; > struct page *page; > + struct page **pages; > void *ptr; > int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); > + size_t size = nr_pages * sizeof(struct page *); > > - bitmap = kzalloc(bitmap_size, GFP_KERNEL); > + size += bitmap_size; > + bitmap = kzalloc(size, GFP_KERNEL); > if (!bitmap) > goto no_bitmap; > + pages = (void *)bitmap + bitmap_size; So you stuck a bitmap field in front of the array then? Why not just define a structure where this is clearly defined instead of doing the casting. > > if (IS_ENABLED(CONFIG_CMA)) > ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page); > @@ -348,9 +352,14 @@ static int __init atomic_pool_init(void) > ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot, > &page, NULL); > if (ptr) { > + int i; > + > + for (i = 0; i < nr_pages; i++) > + pages[i] = page + i; > + > spin_lock_init(&pool->lock); > pool->vaddr = ptr; > - pool->page = page; > + pool->pages = pages; > pool->bitmap = bitmap; > pool->nr_pages = nr_pages; > pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n", > @@ -481,7 +490,7 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page) > if (pageno < pool->nr_pages) { > bitmap_set(pool->bitmap, pageno, count); > ptr = pool->vaddr + PAGE_SIZE * pageno; > - *ret_page = pool->page + pageno; > + *ret_page = pool->pages[pageno]; > } else { > pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too small!\n" > "Please increase it with coherent_pool= kernel parameter!\n", > -- > 1.7.5.4 >
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote @ Fri, 24 Aug 2012 13:13:23 +0200: > On Fri, Aug 24, 2012 at 11:29:02AM +0300, Hiroshi Doyu wrote: > > struct page **pages is necessary to align with non atomic path in > > __iommu_get_pages(). atomic_pool() has the intialized **pages instead > > of just *page. > > > > Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> > > --- > > arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- > > 1 files changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > > index 601da7a..b14ee64 100644 > > --- a/arch/arm/mm/dma-mapping.c > > +++ b/arch/arm/mm/dma-mapping.c > > @@ -296,7 +296,7 @@ struct dma_pool { > > unsigned long *bitmap; > > unsigned long nr_pages; > > void *vaddr; > > - struct page *page; > > + struct page **pages; > > }; > > > > static struct dma_pool atomic_pool = { > > @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) > > unsigned long nr_pages = pool->size >> PAGE_SHIFT; > > unsigned long *bitmap; > > struct page *page; > > + struct page **pages; > > void *ptr; > > int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); > > + size_t size = nr_pages * sizeof(struct page *); > > > > - bitmap = kzalloc(bitmap_size, GFP_KERNEL); > > + size += bitmap_size; > > + bitmap = kzalloc(size, GFP_KERNEL); > > if (!bitmap) > > goto no_bitmap; > > + pages = (void *)bitmap + bitmap_size; > > So you stuck a bitmap field in front of the array then? > Why not just define a structure where this is clearly defined > instead of doing the casting. I just wanted to allocate only once for the members "pool->bitmap" and "pool->pages" at once. Since the size of a whole bitmap isn't known in advance, I couldn't find any fixed type for this bitmap, which pointer can be shifted without casting. IOW, they are variable length.
Hello, On Friday, August 24, 2012 1:52 PM Hiroshi Doyu wrote: > Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote @ Fri, 24 Aug 2012 13:13:23 +0200: > > > On Fri, Aug 24, 2012 at 11:29:02AM +0300, Hiroshi Doyu wrote: > > > struct page **pages is necessary to align with non atomic path in > > > __iommu_get_pages(). atomic_pool() has the intialized **pages instead > > > of just *page. > > > > > > Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> > > > --- > > > arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- > > > 1 files changed, 13 insertions(+), 4 deletions(-) > > > > > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > > > index 601da7a..b14ee64 100644 > > > --- a/arch/arm/mm/dma-mapping.c > > > +++ b/arch/arm/mm/dma-mapping.c > > > @@ -296,7 +296,7 @@ struct dma_pool { > > > unsigned long *bitmap; > > > unsigned long nr_pages; > > > void *vaddr; > > > - struct page *page; > > > + struct page **pages; > > > }; > > > > > > static struct dma_pool atomic_pool = { > > > @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) > > > unsigned long nr_pages = pool->size >> PAGE_SHIFT; > > > unsigned long *bitmap; > > > struct page *page; > > > + struct page **pages; > > > void *ptr; > > > int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); > > > + size_t size = nr_pages * sizeof(struct page *); > > > > > > - bitmap = kzalloc(bitmap_size, GFP_KERNEL); > > > + size += bitmap_size; > > > + bitmap = kzalloc(size, GFP_KERNEL); > > > if (!bitmap) > > > goto no_bitmap; > > > + pages = (void *)bitmap + bitmap_size; > > > > So you stuck a bitmap field in front of the array then? > > Why not just define a structure where this is clearly defined > > instead of doing the casting. > > I just wanted to allocate only once for the members "pool->bitmap" and > "pool->pages" at once. Since the size of a whole bitmap isn't known in > advance, I couldn't find any fixed type for this bitmap, which pointer > can be shifted without casting. IOW, they are variable length. IMHO it is better to avoid any non-trivial things in generic arch code. Merging those 2 allocations doesn't save any significant bit of memory and might confuse someone. Better just allocate them separately. Best regards
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 601da7a..b14ee64 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -296,7 +296,7 @@ struct dma_pool { unsigned long *bitmap; unsigned long nr_pages; void *vaddr; - struct page *page; + struct page **pages; }; static struct dma_pool atomic_pool = { @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) unsigned long nr_pages = pool->size >> PAGE_SHIFT; unsigned long *bitmap; struct page *page; + struct page **pages; void *ptr; int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); + size_t size = nr_pages * sizeof(struct page *); - bitmap = kzalloc(bitmap_size, GFP_KERNEL); + size += bitmap_size; + bitmap = kzalloc(size, GFP_KERNEL); if (!bitmap) goto no_bitmap; + pages = (void *)bitmap + bitmap_size; if (IS_ENABLED(CONFIG_CMA)) ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page); @@ -348,9 +352,14 @@ static int __init atomic_pool_init(void) ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot, &page, NULL); if (ptr) { + int i; + + for (i = 0; i < nr_pages; i++) + pages[i] = page + i; + spin_lock_init(&pool->lock); pool->vaddr = ptr; - pool->page = page; + pool->pages = pages; pool->bitmap = bitmap; pool->nr_pages = nr_pages; pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n", @@ -481,7 +490,7 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page) if (pageno < pool->nr_pages) { bitmap_set(pool->bitmap, pageno, count); ptr = pool->vaddr + PAGE_SIZE * pageno; - *ret_page = pool->page + pageno; + *ret_page = pool->pages[pageno]; } else { pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too small!\n" "Please increase it with coherent_pool= kernel parameter!\n",
struct page **pages is necessary to align with non atomic path in __iommu_get_pages(). atomic_pool() has the intialized **pages instead of just *page. Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> --- arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- 1 files changed, 13 insertions(+), 4 deletions(-)