Commit b9434c5b authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
Browse files

rbd: define zero_pages() 



Define a new function zero_pages() that zeroes a range of memory
defined by a page array, along the lines of zero_bio_chain().  It
saves and the irq flags like bvec_kmap_irq() does, though I'm not
sure at this point that it's necessary.

Update rbd_img_obj_request_read_callback() to use the new function
if the object request contains page rather than bio data.

For the moment, only bio data is used for osd READ ops.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent b454e36d

drivers/block/rbd.c

+47 −8
Original line number Diff line number Diff line
@@ -970,6 +970,37 @@ static void zero_bio_chain(struct bio *chain, int start_ofs) 
	}

}



/*

 * similar to zero_bio_chain(), zeros data defined by a page array,

 * starting at the given byte offset from the start of the array and

 * continuing up to the given end offset.  The pages array is

 * assumed to be big enough to hold all bytes up to the end.

 */

static void zero_pages(struct page **pages, u64 offset, u64 end)

{

	struct page **page = &pages[offset >> PAGE_SHIFT];



	rbd_assert(end > offset);

	rbd_assert(end - offset <= (u64)SIZE_MAX);

	while (offset < end) {

		size_t page_offset;

		size_t length;

		unsigned long flags;

		void *kaddr;



		page_offset = (size_t)(offset & ~PAGE_MASK);

		length = min(PAGE_SIZE - page_offset, (size_t)(end - offset));

		local_irq_save(flags);

		kaddr = kmap_atomic(*page);

		memset(kaddr + page_offset, 0, length);

		kunmap_atomic(kaddr);

		local_irq_restore(flags);



		offset += length;

		page++;

	}

}



/*

 * Clone a portion of a bio, starting at the given byte offset

 * and continuing for the number of bytes indicated.
@@ -1352,9 +1383,12 @@ static bool img_request_layered_test(struct rbd_img_request *img_request) 
static void

rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)

{

	u64 xferred = obj_request->xferred;

	u64 length = obj_request->length;



	dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,

		obj_request, obj_request->img_request, obj_request->result,

		obj_request->xferred, obj_request->length);

		xferred, length);

	/*

	 * ENOENT means a hole in the image.  We zero-fill the

	 * entire length of the request.  A short read also implies
@@ -1362,15 +1396,20 @@ rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request) 
	 * update the xferred count to indicate the whole request

	 * was satisfied.

	 */

	BUG_ON(obj_request->type != OBJ_REQUEST_BIO);

	rbd_assert(obj_request->type != OBJ_REQUEST_NODATA);

	if (obj_request->result == -ENOENT) {

		if (obj_request->type == OBJ_REQUEST_BIO)

			zero_bio_chain(obj_request->bio_list, 0);

		else

			zero_pages(obj_request->pages, 0, length);

		obj_request->result = 0;

		obj_request->xferred = obj_request->length;

	} else if (obj_request->xferred < obj_request->length &&

			!obj_request->result) {

		zero_bio_chain(obj_request->bio_list, obj_request->xferred);

		obj_request->xferred = obj_request->length;

		obj_request->xferred = length;

	} else if (xferred < length && !obj_request->result) {

		if (obj_request->type == OBJ_REQUEST_BIO)

			zero_bio_chain(obj_request->bio_list, xferred);

		else

			zero_pages(obj_request->pages, xferred, length);

		obj_request->xferred = length;

	}

	obj_request_done_set(obj_request);

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE