On Wed, Oct 24, 2018 at 12:34:49AM +0300, Igor Stoppa wrote:

+static __always_inline

That's far too large for inline.

+bool wr_memset(const void *dst, const int c, size_t n_bytes)
+{
+	size_t size;
+	unsigned long flags;
+	uintptr_t d = (uintptr_t)dst;
+
+	if (WARN(!__is_wr_after_init(dst, n_bytes), WR_ERR_RANGE_MSG))
+		return false;
+	while (n_bytes) {
+		struct page *page;
+		uintptr_t base;
+		uintptr_t offset;
+		uintptr_t offset_complement;
+
+		local_irq_save(flags);
+		page = virt_to_page(d);
+		offset = d & ~PAGE_MASK;
+		offset_complement = PAGE_SIZE - offset;
+		size = min(n_bytes, offset_complement);
+		base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL);
+		if (WARN(!base, WR_ERR_PAGE_MSG)) {
+			local_irq_restore(flags);
+			return false;
+		}
+		memset((void *)(base + offset), c, size);
+		vunmap((void *)base);

BUG

+		d += size;
+		n_bytes -= size;
+		local_irq_restore(flags);
+	}
+	return true;
+}
+
+static __always_inline

Similarly large

+bool wr_memcpy(const void *dst, const void *src, size_t n_bytes)
+{
+	size_t size;
+	unsigned long flags;
+	uintptr_t d = (uintptr_t)dst;
+	uintptr_t s = (uintptr_t)src;
+
+	if (WARN(!__is_wr_after_init(dst, n_bytes), WR_ERR_RANGE_MSG))
+		return false;
+	while (n_bytes) {
+		struct page *page;
+		uintptr_t base;
+		uintptr_t offset;
+		uintptr_t offset_complement;
+
+		local_irq_save(flags);
+		page = virt_to_page(d);
+		offset = d & ~PAGE_MASK;
+		offset_complement = PAGE_SIZE - offset;
+		size = (size_t)min(n_bytes, offset_complement);
+		base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL);
+		if (WARN(!base, WR_ERR_PAGE_MSG)) {
+			local_irq_restore(flags);
+			return false;
+		}
+		__write_once_size((void *)(base + offset), (void *)s, size);
+		vunmap((void *)base);

Similarly BUG.

+		d += size;
+		s += size;
+		n_bytes -= size;
+		local_irq_restore(flags);
+	}
+	return true;
+}

+static __always_inline

Guess what..

+uintptr_t __wr_rcu_ptr(const void *dst_p_p, const void *src_p)
+{
+	unsigned long flags;
+	struct page *page;
+	void *base;
+	uintptr_t offset;
+	const size_t size = sizeof(void *);
+
+	if (WARN(!__is_wr_after_init(dst_p_p, size), WR_ERR_RANGE_MSG))
+		return (uintptr_t)NULL;
+	local_irq_save(flags);
+	page = virt_to_page(dst_p_p);
+	offset = (uintptr_t)dst_p_p & ~PAGE_MASK;
+	base = vmap(&page, 1, VM_MAP, PAGE_KERNEL);
+	if (WARN(!base, WR_ERR_PAGE_MSG)) {
+		local_irq_restore(flags);
+		return (uintptr_t)NULL;
+	}
+	rcu_assign_pointer((*(void **)(offset + (uintptr_t)base)), src_p);
+	vunmap(base);

Also still bug.

+	local_irq_restore(flags);
+	return (uintptr_t)src_p;
+}

Also, I see an amount of duplication here that shows you're not nearly
lazy enough.