(Had sent this to you directly. Reposting for the whole cc list.)
On Fri, Apr 07, 2017 at 04:28:53PM -0400, Jérôme Glisse wrote:
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -212,28 +215,25 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
* THE finalize_and_map() CALLBACK MUST NOT CHANGE ANY OF THE SRC OR DST ARRAY
* ENTRIES OR BAD THINGS WILL HAPPEN !
*/
-struct migrate_vma_ops {
- void (*alloc_and_copy)(struct vm_area_struct *vma,
- const unsigned long *src,
- unsigned long *dst,
- unsigned long start,
- unsigned long end,
- void *private);
- void (*finalize_and_map)(struct vm_area_struct *vma,
- const unsigned long *src,
- const unsigned long *dst,
- unsigned long start,
- unsigned long end,
- void *private);
+struct migrate_dma_ops {
+ void (*alloc_and_copy)(struct migrate_dma_ctx *ctx);
+ void (*finalize_and_map)(struct migrate_dma_ctx *ctx);
+};
+
+struct migrate_dma_ctx {
+ const struct migrate_dma_ops *ops;
+ unsigned long *dst;
+ unsigned long *src;
+ unsigned long cpages;
+ unsigned long npages;
Could you add this so we can still pass arguments to the callbacks?
void *private;
};
-int migrate_vma(const struct migrate_vma_ops *ops,
+int migrate_vma(struct migrate_dma_ctx *ctx,
struct vm_area_struct *vma,
unsigned long start,
- unsigned long end,
- unsigned long *src,
- unsigned long *dst,
- void *private);
+ unsigned long end);
+int migrate_dma(struct migrate_dma_ctx *migrate_ctx);
+
#endif /* CONFIG_MIGRATION */
...%<...
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2803,16 +2761,76 @@ int migrate_vma(const struct migrate_vma_ops *ops,
* Note that migration can fail in migrate_vma_struct_page() for each
* individual page.
*/
- ops->alloc_and_copy(vma, src, dst, start, end, private);
+ migrate_ctx->ops->alloc_and_copy(migrate_ctx);
/* This does the real migration of struct page */
- migrate_vma_pages(&migrate);
+ migrate_dma_pages(migrate_ctx, vma, start, end);
- ops->finalize_and_map(vma, src, dst, start, end, private);
+ migrate_ctx->ops->finalize_and_map(migrate_ctx);
/* Unlock and remap pages */
- migrate_vma_finalize(&migrate);
+ migrate_dma_finalize(migrate_ctx);
return 0;
}
EXPORT_SYMBOL(migrate_vma);
+
+/*
+ * migrate_dma() - migrate an array of pages using a device DMA engine
+ *
+ * @migrate_ctx: migrate context structure
+ *
+ * The context structure must have its src fields pointing to an array of
+ * migrate pfn entry each corresponding to a valid page and each page being
+ * lock. The dst entry must by an array as big as src, it will be use during
+ * migration to store the destination pfn.
+ *
+ */
+int migrate_dma(struct migrate_dma_ctx *migrate_ctx)
+{
+ unsigned long i;
+
+ /* Sanity check the arguments */
+ if (!migrate_ctx->ops || !migrate_ctx->src || !migrate_ctx->dst)
+ return -EINVAL;
+
+ /* Below code should be hidden behind some DEBUG config */
+ for (i = 0; i < migrate_ctx->npages; ++i) {
+ const unsigned long mask = MIGRATE_PFN_VALID |
+ MIGRATE_PFN_LOCKED;
This line is before the pages are locked. I think it should be
MIGRATE_PFN_MIGRATE;
+
+ if (!(migrate_ctx->src[i] & mask))
+ return -EINVAL;
+ }
+
+ /* Lock and isolate page */
+ migrate_dma_prepare(migrate_ctx);
+ if (!migrate_ctx->cpages)
+ return 0;
+
+ /* Unmap pages */
+ migrate_dma_unmap(migrate_ctx);
+ if (!migrate_ctx->cpages)
+ return 0;
+
+ /*
+ * At this point pages are locked and unmapped, and thus they have
+ * stable content and can safely be copied to destination memory that
+ * is allocated by the callback.
+ *
+ * Note that migration can fail in migrate_vma_struct_page() for each
+ * individual page.
+ */
+ migrate_ctx->ops->alloc_and_copy(migrate_ctx);
+
+ /* This does the real migration of struct page */
+ migrate_dma_pages(migrate_ctx, NULL, 0, 0);
+
+ migrate_ctx->ops->finalize_and_map(migrate_ctx);
+
+ /* Unlock and remap pages */
+ migrate_dma_finalize(migrate_ctx);
+
+ return 0;
+}
+EXPORT_SYMBOL(migrate_dma);
--
Reza Arbab
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