[PREVIEW] [PATCH RESEND 2/4] staging: erofs: introduce erofs_grab_bio

[Chao Yu]

On 2018/8/1 14:04, Gao Xiang wrote:
> this patch renames prepare_bio to erofs_grab_bio, and
> adds a nofail option in order to retry in the bio allocator.
> 
> Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
> ---
>  drivers/staging/erofs/data.c      | 12 ++++++++++--
>  drivers/staging/erofs/internal.h  | 35 +++++++++++++++++------------------
>  drivers/staging/erofs/unzip_vle.c |  4 ++--
>  3 files changed, 29 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/staging/erofs/data.c b/drivers/staging/erofs/data.c
> index ac263a1..2426eda 100644
> --- a/drivers/staging/erofs/data.c
> +++ b/drivers/staging/erofs/data.c
> @@ -60,7 +60,8 @@ struct page *erofs_get_meta_page(struct super_block *sb,
>  		struct bio *bio;
>  		int err;
>  
> -		bio = prepare_bio(sb, blkaddr, 1, read_endio);
> +		bio = erofs_grab_bio(sb, blkaddr, 1, read_endio, true);
> +
>  		err = bio_add_page(bio, page, PAGE_SIZE, 0);
>  		BUG_ON(err != PAGE_SIZE);
>  
> @@ -278,7 +279,14 @@ static inline struct bio *erofs_read_raw_page(
>  		if (nblocks > BIO_MAX_PAGES)
>  			nblocks = BIO_MAX_PAGES;
>  
> -		bio = prepare_bio(inode->i_sb, blknr, nblocks, read_endio);
> +		bio = erofs_grab_bio(inode->i_sb,
> +			blknr, nblocks, read_endio, false);
> +
> +		if (unlikely(IS_ERR(bio))) {
> +			err = PTR_ERR(bio);
> +			bio = NULL;
> +			goto err_out;
> +		}
>  	}
>  
>  	err = bio_add_page(bio, page, PAGE_SIZE, 0);
> diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
> index 4518729..acce2d6 100644
> --- a/drivers/staging/erofs/internal.h
> +++ b/drivers/staging/erofs/internal.h
> @@ -419,26 +419,25 @@ struct erofs_map_blocks {
>  #define EROFS_GET_BLOCKS_RAW    0x0001
>  
>  /* data.c */
> -static inline struct bio *prepare_bio(
> -	struct super_block *sb,
> -	erofs_blk_t blkaddr, unsigned nr_pages,
> -	bio_end_io_t endio)
> +static inline struct bio *
> +erofs_grab_bio(struct super_block *sb,
> +	       erofs_blk_t blkaddr, unsigned nr_pages,
> +	       bio_end_io_t endio, bool nofail)
>  {
> -	gfp_t gfp = GFP_NOIO;
> -	struct bio *bio = bio_alloc(gfp, nr_pages);
> -
> -	if (unlikely(bio == NULL) &&
> -		(current->flags & PF_MEMALLOC)) {
> -		do {
> -			nr_pages /= 2;
> -			if (unlikely(!nr_pages)) {
> -				bio = bio_alloc(gfp | __GFP_NOFAIL, 1);
> -				BUG_ON(bio == NULL);
> -				break;
> +	const gfp_t gfp = GFP_NOIO;
> +	struct bio *bio;
> +
> +	do {
> +		if (nr_pages == 1) {
> +			bio = bio_alloc(gfp | (nofail ? __GFP_NOFAIL : 0), 1);
> +			if (unlikely(bio == NULL)) {
> +				DBG_BUGON(nofail);
> +				return ERR_PTR(-ENOMEM);
>  			}
> -			bio = bio_alloc(gfp, nr_pages);
> -		} while (bio == NULL);
> -	}
> +		}
> +		bio = bio_alloc(gfp, nr_pages);

Need to cover this bio_alloc, so should initialize gfp as:

gfp_t gfp = GFP_NOIO | (nofail ? __GFP_NOFAIL : 0);

Thanks,

> +		nr_pages /= 2;
> +	} while (unlikely(bio == NULL));
>  
>  	bio->bi_end_io = endio;
>  	bio_set_dev(bio, sb->s_bdev);
> diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
> index 6d3ab31..be3929d 100644
> --- a/drivers/staging/erofs/unzip_vle.c
> +++ b/drivers/staging/erofs/unzip_vle.c
> @@ -1212,8 +1212,8 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
>  		}
>  
>  		if (bio == NULL) {
> -			bio = prepare_bio(sb, first_index + i,
> -				BIO_MAX_PAGES, z_erofs_vle_read_endio);
> +			bio = erofs_grab_bio(sb, first_index + i,
> +				BIO_MAX_PAGES, z_erofs_vle_read_endio, true);
>  			bio->bi_private = tagptr_cast_ptr(bi_private);
>  
>  			++nr_bios;
>