On 1/24/23 09:01, 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>
cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
cc: Jens Axboe <axboe@xxxxxxxxx>
cc: Jan Kara <jack@xxxxxxx>
cc: Christoph Hellwig <hch@xxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
cc: linux-block@xxxxxxxxxxxxxxx
---
Notes:
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 | 21 +++++++++++++++++++++
include/linux/bio.h | 3 ++-
include/linux/blk_types.h | 1 +
4 files changed, 27 insertions(+), 4 deletions(-)
Neatly avoiding any use of FOLL_PIN or FOLL_GET, good. :)
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
--
John Hubbard
NVIDIA
diff --git a/block/bio.c b/block/bio.c
index 851c23641a0d..fc45aaa97696 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1176,7 +1176,7 @@ 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);
@@ -1496,8 +1496,8 @@ 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 4c3b3325219a..32b252903f9a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -425,6 +425,27 @@ 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);
+/*
+ * Set the cleanup mode for a bio from an iterator and the extraction flags.
+ */
+static inline void bio_set_cleanup_mode(struct bio *bio, struct iov_iter *iter)
+{
+ if (iov_iter_extract_will_pin(iter))
+ bio_set_flag(bio, BIO_PAGE_PINNED);
+}
+
+/*
+ * 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, void *owner);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 805957c99147..b2c09997d79c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -484,7 +484,8 @@ 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 7daa261f4f98..a0e339ff3d09 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -318,6 +318,7 @@ 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 */
