zram: use memcpy_from_bvec in zram_bvec_write

Use memcpy_from_bvec instead of open coding the logic.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Ira Weiny <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/zram/zram_drv.c

···
 {
 	int ret;
 	struct page *page = NULL;
-	void *src;
 	struct bio_vec vec;
 
 	vec = *bvec;
···
 		if (ret)
 			goto out;
 
-		src = kmap_atomic(bvec->bv_page);
 		dst = kmap_atomic(page);
-		memcpy(dst + offset, src + bvec->bv_offset, bvec->bv_len);
+		memcpy_from_bvec(dst + offset, bvec);
 		kunmap_atomic(dst);
-		kunmap_atomic(src);
 
 		vec.bv_page = page;
 		vec.bv_len = PAGE_SIZE;