[PATCH v3 03/18] io_uring/memmap: flag vmap'ed regions

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

Add internal flags for struct io_mapped_region. The first flag we need
is IO_REGION_F_VMAPPED, that indicates that the pointer has to be
unmapped on region destruction. For now all regions are vmap'ed, so it's
set unconditionally.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
 include/linux/io_uring_types.h |  5 +++--
 io_uring/memmap.c              | 14 ++++++++++----
 io_uring/memmap.h              |  2 +-
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index adb36e0da40e..4cee414080fd 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -77,8 +77,9 @@ struct io_hash_table {
 
 struct io_mapped_region {
 	struct page		**pages;
-	void			*vmap_ptr;
-	size_t			nr_pages;
+	void			*ptr;
+	unsigned		nr_pages;
+	unsigned		flags;
 };
 
 /*
diff --git a/io_uring/memmap.c b/io_uring/memmap.c
index a0d4151d11af..31fb8c8ffe4e 100644
--- a/io_uring/memmap.c
+++ b/io_uring/memmap.c
@@ -202,14 +202,19 @@ void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 	return ERR_PTR(-ENOMEM);
 }
 
+enum {
+	/* memory was vmap'ed for the kernel, freeing the region vunmap's it */
+	IO_REGION_F_VMAP			= 1,
+};
+
 void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr)
 {
 	if (mr->pages) {
 		unpin_user_pages(mr->pages, mr->nr_pages);
 		kvfree(mr->pages);
 	}
-	if (mr->vmap_ptr)
-		vunmap(mr->vmap_ptr);
+	if ((mr->flags & IO_REGION_F_VMAP) && mr->ptr)
+		vunmap(mr->ptr);
 	if (mr->nr_pages && ctx->user)
 		__io_unaccount_mem(ctx->user, mr->nr_pages);
 
@@ -225,7 +230,7 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr,
 	void *vptr;
 	u64 end;
 
-	if (WARN_ON_ONCE(mr->pages || mr->vmap_ptr || mr->nr_pages))
+	if (WARN_ON_ONCE(mr->pages || mr->ptr || mr->nr_pages))
 		return -EFAULT;
 	if (memchr_inv(&reg->__resv, 0, sizeof(reg->__resv)))
 		return -EINVAL;
@@ -260,8 +265,9 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr,
 	}
 
 	mr->pages = pages;
-	mr->vmap_ptr = vptr;
+	mr->ptr = vptr;
 	mr->nr_pages = nr_pages;
+	mr->flags |= IO_REGION_F_VMAP;
 	return 0;
 out_free:
 	if (pages_accounted)
diff --git a/io_uring/memmap.h b/io_uring/memmap.h
index f361a635b6c7..2096a8427277 100644
--- a/io_uring/memmap.h
+++ b/io_uring/memmap.h
@@ -28,7 +28,7 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr,
 
 static inline void *io_region_get_ptr(struct io_mapped_region *mr)
 {
-	return mr->vmap_ptr;
+	return mr->ptr;
 }
 
 static inline bool io_region_is_set(struct io_mapped_region *mr)
-- 
2.47.1