Commit 1dfa0f68 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add a helper to free bio bounce buffer pages 



The code sniplet to walk all bio_vecs and free their pages is opencoded in
way to many places, so factor it into a helper.  Also convert the slightly
more complex cases in bio_kern_endio and __bio_copy_iov where we break
the freeing from an existing loop into a separate one.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent ddad8dd0

block/bio.c

+33 −32
Original line number Diff line number Diff line
@@ -1048,7 +1048,7 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, 
}



static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count,

			  int to_user, int from_user, int do_free_page)

                          int to_user, int from_user)

{

	int ret = 0, i;

	struct bio_vec *bvec;
@@ -1090,14 +1090,20 @@ static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_c 
				iov_off = 0;

			}

		}



		if (do_free_page)

			__free_page(bvec->bv_page);

	}



	return ret;

}



static void bio_free_pages(struct bio *bio)

{

	struct bio_vec *bvec;

	int i;



	bio_for_each_segment_all(bvec, bio, i)

		__free_page(bvec->bv_page);

}



/**

 *	bio_uncopy_user	-	finish previously mapped bio

 *	@bio: bio being terminated
@@ -1108,8 +1114,7 @@ static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_c 
int bio_uncopy_user(struct bio *bio)

{

	struct bio_map_data *bmd = bio->bi_private;

	struct bio_vec *bvec;

	int ret = 0, i;

	int ret = 0;



	if (!bio_flagged(bio, BIO_NULL_MAPPED)) {

		/*
@@ -1118,11 +1123,9 @@ int bio_uncopy_user(struct bio *bio) 
		 */

		if (current->mm)

			ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,

					     bio_data_dir(bio) == READ,

					     0, bmd->is_our_pages);

		else if (bmd->is_our_pages)

			bio_for_each_segment_all(bvec, bio, i)

				__free_page(bvec->bv_page);

					     bio_data_dir(bio) == READ, 0);

		if (bmd->is_our_pages)

			bio_free_pages(bio);

	}

	kfree(bmd);

	bio_put(bio);
@@ -1149,7 +1152,6 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
			      int write_to_vm, gfp_t gfp_mask)

{

	struct bio_map_data *bmd;

	struct bio_vec *bvec;

	struct page *page;

	struct bio *bio;

	int i, ret;
@@ -1238,7 +1240,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
	 */

	if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||

	    (map_data && map_data->from_user)) {

		ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0);

		ret = __bio_copy_iov(bio, iov, iov_count, 0, 1);

		if (ret)

			goto cleanup;

	}
@@ -1247,9 +1249,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
	return bio;

cleanup:

	if (!map_data)

		bio_for_each_segment_all(bvec, bio, i)

			__free_page(bvec->bv_page);



		bio_free_pages(bio);

	bio_put(bio);

out_bmd:

	kfree(bmd);
@@ -1510,22 +1510,22 @@ EXPORT_SYMBOL(bio_map_kern); 


static void bio_copy_kern_endio(struct bio *bio, int err)

{

	struct bio_vec *bvec;

	const int read = bio_data_dir(bio) == READ;

	bio_free_pages(bio);

	bio_put(bio);

}



static void bio_copy_kern_endio_read(struct bio *bio, int err)

{

	char *p = bio->bi_private;

	struct bio_vec *bvec;

	int i;



	bio_for_each_segment_all(bvec, bio, i) {

		char *addr = page_address(bvec->bv_page);



		if (read)

			memcpy(p, addr, bvec->bv_len);



		__free_page(bvec->bv_page);

		memcpy(p, page_address(bvec->bv_page), bvec->bv_len);

		p += bvec->bv_len;

	}



	bio_put(bio);

	bio_copy_kern_endio(bio, err);

}



/**
@@ -1545,10 +1545,9 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, 
	unsigned long kaddr = (unsigned long)data;

	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;

	unsigned long start = kaddr >> PAGE_SHIFT;

	struct bio_vec *bvec;

	struct bio *bio;

	void *p = data;

	int nr_pages = 0, i;

	int nr_pages = 0;



	/*

	 * Overflow, abort
@@ -1582,16 +1581,18 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, 
		p += bytes;

	}



	if (!reading)

		bio->bi_rw |= REQ_WRITE;



	if (reading) {

		bio->bi_end_io = bio_copy_kern_endio_read;

		bio->bi_private = data;

	} else {

		bio->bi_end_io = bio_copy_kern_endio;

		bio->bi_rw |= REQ_WRITE;

	}



	return bio;



cleanup:

	bio_for_each_segment_all(bvec, bio, i)

		__free_page(bvec->bv_page);

	bio_free_pages(bio);

	bio_put(bio);

	return ERR_PTR(-ENOMEM);

}

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