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Commit c8db4448 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

block: Don't save/copy bvec array anymore 



Now that drivers have been converted to the bvec_iter primitives, they
shouldn't be modifying the biovec anymore and thus saving it is
unnecessary - code that was previously making a backup of the bvec array
can now just save bio->bi_iter.

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
parent 1c3b13e6

fs/bio.c

+13 −41
Original line number Diff line number Diff line
@@ -967,60 +967,33 @@ void bio_copy_data(struct bio *dst, struct bio *src) 
EXPORT_SYMBOL(bio_copy_data);



struct bio_map_data {

	struct bio_vec *iovecs;

	struct sg_iovec *sgvecs;

	int nr_sgvecs;

	int is_our_pages;

	struct sg_iovec sgvecs[];

};



static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,

			     struct sg_iovec *iov, int iov_count,

			     int is_our_pages)

{

	memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);

	memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);

	bmd->nr_sgvecs = iov_count;

	bmd->is_our_pages = is_our_pages;

	bio->bi_private = bmd;

}



static void bio_free_map_data(struct bio_map_data *bmd)

{

	kfree(bmd->iovecs);

	kfree(bmd->sgvecs);

	kfree(bmd);

}



static struct bio_map_data *bio_alloc_map_data(int nr_segs,

					       unsigned int iov_count,

					       gfp_t gfp_mask)

{

	struct bio_map_data *bmd;



	if (iov_count > UIO_MAXIOV)

		return NULL;



	bmd = kmalloc(sizeof(*bmd), gfp_mask);

	if (!bmd)

		return NULL;



	bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);

	if (!bmd->iovecs) {

		kfree(bmd);

		return NULL;

	return kmalloc(sizeof(struct bio_map_data) +

		       sizeof(struct sg_iovec) * iov_count, gfp_mask);

}



	bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);

	if (bmd->sgvecs)

		return bmd;



	kfree(bmd->iovecs);

	kfree(bmd);

	return NULL;

}



static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,

			  struct sg_iovec *iov, int iov_count,

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

			  int to_user, int from_user, int do_free_page)

{

	int ret = 0, i;
@@ -1030,7 +1003,7 @@ static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, 


	bio_for_each_segment_all(bvec, bio, i) {

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

		unsigned int bv_len = iovecs[i].bv_len;

		unsigned int bv_len = bvec->bv_len;



		while (bv_len && iov_idx < iov_count) {

			unsigned int bytes;
@@ -1090,14 +1063,14 @@ int bio_uncopy_user(struct bio *bio) 
		 * don't copy into a random user address space, just free.

		 */

		if (current->mm)

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

					     bmd->nr_sgvecs, bio_data_dir(bio) == READ,

			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_free_map_data(bmd);

	kfree(bmd);

	bio_put(bio);

	return ret;

}
@@ -1211,7 +1184,7 @@ 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, bio->bi_io_vec, iov, iov_count, 0, 1, 0);

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

		if (ret)

			goto cleanup;

	}
@@ -1225,7 +1198,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 


	bio_put(bio);

out_bmd:

	bio_free_map_data(bmd);

	kfree(bmd);

	return ERR_PTR(ret);

}
@@ -1542,16 +1515,15 @@ static void bio_copy_kern_endio(struct bio *bio, int err) 


	bio_for_each_segment_all(bvec, bio, i) {

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

		int len = bmd->iovecs[i].bv_len;



		if (read)

			memcpy(p, addr, len);

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



		__free_page(bvec->bv_page);

		p += len;

		p += bvec->bv_len;

	}



	bio_free_map_data(bmd);

	kfree(bmd);

	bio_put(bio);

}