mm: cma_alloc: allow to specify GFP mask

Most users of this interface just want to use it with the default
GFP_KERNEL flags, but for cases where DMA memory is allocated it may be
called from a different context.

No functional change yet, just passing through the flag to the
underlying alloc_contig_range function.

Link: http://lkml.kernel.org/r/20170127172328.18574-2-l.stach@pengutronix.de
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alexander Graf <agraf@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/kvm/book3s_hv_builtin.c

@@ -56,7 +56,8 @@ struct page *kvm_alloc_hpt_cma(unsigned long nr_pages)
 {
 	VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
 
-	return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_ALIGN_PAGES));
+	return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_ALIGN_PAGES),
+			 GFP_KERNEL);
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt_cma);
 

drivers/base/dma-contiguous.c

@@ -193,7 +193,7 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return cma_alloc(dev_get_cma_area(dev), count, align);
+	return cma_alloc(dev_get_cma_area(dev), count, align, GFP_KERNEL);
 }
 
 /**

include/linux/cma.h

@@ -29,6 +29,7 @@ extern int __init cma_declare_contiguous(phys_addr_t base,
 extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 					unsigned int order_per_bit,
 					struct cma **res_cma);
-extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align);
+extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
+			      gfp_t gfp_mask);
 extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count);
 #endif

mm/cma.c

@@ -357,7 +357,8 @@ err:
  * This function allocates part of contiguous memory on specific
  * contiguous memory area.
  */
-struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
+struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
+		       gfp_t gfp_mask)
 {
 	unsigned long mask, offset;
 	unsigned long pfn = -1;
@@ -403,7 +404,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
 		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
-					 GFP_KERNEL);
+					 gfp_mask);
 		mutex_unlock(&cma_mutex);
 		if (ret == 0) {
 			page = pfn_to_page(pfn);

mm/cma_debug.c

@@ -138,7 +138,7 @@ static int cma_alloc_mem(struct cma *cma, int count)
 	if (!mem)
 		return -ENOMEM;
 
-	p = cma_alloc(cma, count, 0);
+	p = cma_alloc(cma, count, 0, GFP_KERNEL);
 	if (!p) {
 		kfree(mem);
 		return -ENOMEM;