From b9434c5b43d1a90e762fe64169862fb198746935 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 19 Apr 2013 15:34:50 -0500 Subject: [PATCH] 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: Alex Elder Reviewed-by: Josh Durgin --- drivers/block/rbd.c | 55 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 47 insertions(+), 8 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index e208cec808dc..06bbd55c0ea1 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -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) { - zero_bio_chain(obj_request->bio_list, 0); + 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); } -- 2.20.1