On Mon 22-05-23 21:57:42, David Howells wrote:
> Add BIO_PAGE_PINNED to indicate that the pages in a bio are pinned
> (FOLL_PIN) and that the pin will need removing.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
> cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> cc: Jens Axboe <axboe@xxxxxxxxx>
> cc: Jan Kara <jack@xxxxxxx>
> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
> cc: linux-block@xxxxxxxxxxxxxxx
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
>
> Notes:
> ver #10)
> - Drop bio_set_cleanup_mode(), open coding it instead.
>
> ver #9)
> - Only consider pinning in bio_set_cleanup_mode(). Ref'ing pages in
> struct bio is going away.
> - page_put_unpin() is removed; call unpin_user_page() and put_page()
> directly.
> - Use bio_release_page() in __bio_release_pages().
> - BIO_PAGE_PINNED and BIO_PAGE_REFFED can't both be set, so use if-else
> when testing both of them.
>
> ver #8)
> - Move the infrastructure to clean up pinned pages to this patch [hch].
> - Put BIO_PAGE_PINNED before BIO_PAGE_REFFED as the latter should
> probably be removed at some point. FOLL_PIN can then be renumbered
> first.
>
> block/bio.c | 6 +++---
> block/blk.h | 12 ++++++++++++
> include/linux/bio.h | 3 ++-
> include/linux/blk_types.h | 1 +
> 4 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index 8516adeaea26..17bd01ecde36 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -1169,7 +1169,7 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty)
> bio_for_each_segment_all(bvec, bio, iter_all) {
> if (mark_dirty && !PageCompound(bvec->bv_page))
> set_page_dirty_lock(bvec->bv_page);
> - put_page(bvec->bv_page);
> + bio_release_page(bio, bvec->bv_page);
> }
> }
> EXPORT_SYMBOL_GPL(__bio_release_pages);
> @@ -1489,8 +1489,8 @@ void bio_set_pages_dirty(struct bio *bio)
> * the BIO and re-dirty the pages in process context.
> *
> * It is expected that bio_check_pages_dirty() will wholly own the BIO from
> - * here on. It will run one put_page() against each page and will run one
> - * bio_put() against the BIO.
> + * here on. It will unpin each page and will run one bio_put() against the
> + * BIO.
> */
>
> static void bio_dirty_fn(struct work_struct *work);
> diff --git a/block/blk.h b/block/blk.h
> index 45547bcf1119..e1ded2ccb3ca 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -420,6 +420,18 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
> struct page *page, unsigned int len, unsigned int offset,
> unsigned int max_sectors, bool *same_page);
>
> +/*
> + * Clean up a page appropriately, where the page may be pinned, may have a
> + * ref taken on it or neither.
> + */
> +static inline void bio_release_page(struct bio *bio, struct page *page)
> +{
> + if (bio_flagged(bio, BIO_PAGE_PINNED))
> + unpin_user_page(page);
> + else if (bio_flagged(bio, BIO_PAGE_REFFED))
> + put_page(page);
> +}
> +
> struct request_queue *blk_alloc_queue(int node_id);
>
> int disk_scan_partitions(struct gendisk *disk, fmode_t mode);
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index 0922729acd26..8588bcfbc6ef 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -488,7 +488,8 @@ void zero_fill_bio(struct bio *bio);
>
> static inline void bio_release_pages(struct bio *bio, bool mark_dirty)
> {
> - if (bio_flagged(bio, BIO_PAGE_REFFED))
> + if (bio_flagged(bio, BIO_PAGE_REFFED) ||
> + bio_flagged(bio, BIO_PAGE_PINNED))
> __bio_release_pages(bio, mark_dirty);
> }
>
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index dfd2c2cb909d..8ef209e3aa96 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -323,6 +323,7 @@ struct bio {
> * bio flags
> */
> enum {
> + BIO_PAGE_PINNED, /* Unpin pages in bio_release_pages() */
> BIO_PAGE_REFFED, /* put pages in bio_release_pages() */
> BIO_CLONED, /* doesn't own data */
> BIO_BOUNCED, /* bio is a bounce bio */
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
