firmware: Factor out the paged buffer handling code

This is merely a preparation for the upcoming compressed firmware
support and no functional changes.  It moves the code to handle the
paged buffer allocation and mapping out of fallback.c into the main
code, so that they can be used commonly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 2e74a1b73dae..7e12732f4705 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -281,6 +281,58 @@ void fw_free_paged_buf(struct fw_priv *fw_priv)
 	fw_priv->page_array_size = 0;
 	fw_priv->nr_pages = 0;
 }
+
+int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed)
+{
+	/* If the array of pages is too small, grow it */
+	if (fw_priv->page_array_size < pages_needed) {
+		int new_array_size = max(pages_needed,
+					 fw_priv->page_array_size * 2);
+		struct page **new_pages;
+
+		new_pages = kvmalloc_array(new_array_size, sizeof(void *),
+					   GFP_KERNEL);
+		if (!new_pages)
+			return -ENOMEM;
+		memcpy(new_pages, fw_priv->pages,
+		       fw_priv->page_array_size * sizeof(void *));
+		memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
+		       (new_array_size - fw_priv->page_array_size));
+		kvfree(fw_priv->pages);
+		fw_priv->pages = new_pages;
+		fw_priv->page_array_size = new_array_size;
+	}
+
+	while (fw_priv->nr_pages < pages_needed) {
+		fw_priv->pages[fw_priv->nr_pages] =
+			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+
+		if (!fw_priv->pages[fw_priv->nr_pages])
+			return -ENOMEM;
+		fw_priv->nr_pages++;
+	}
+
+	return 0;
+}
+
+int fw_map_paged_buf(struct fw_priv *fw_priv)
+{
+	/* one pages buffer should be mapped/unmapped only once */
+	if (!fw_priv->pages)
+		return 0;
+
+	vunmap(fw_priv->data);
+	fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
+			     PAGE_KERNEL_RO);
+	if (!fw_priv->data)
+		return -ENOMEM;
+
+	/* page table is no longer needed after mapping, let's free */
+	kvfree(fw_priv->pages);
+	fw_priv->pages = NULL;
+
+	return 0;
+}
 #endif
 
 /* direct firmware loading support */