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OpenCloudOS-Kernel
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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2015-01-18 16:16:30 +01:00 committed by Jens Axboe
parent ddad8dd0a1
commit 1dfa0f68c0
1 changed files with 33 additions and 32 deletions
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65
block/bio.c
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@ -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)
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;
}
bio->bi_private = data;
bio->bi_end_io = bio_copy_kern_endio;
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);
}