[PATCH 4/6] block, bio, fs: convert most filesystems to pin_user_pages_fast()

jhubbard.send.patches
2022-02-27T09:34:58Z

From: John Hubbard <jhubbard@nvidia.com>

Use pin_user_pages_fast(), pin_user_page(), and unpin_user_page() calls,
in place of get_user_pages_fast(), get_page() and put_page().

This converts the Direct IO parts of most filesystems over to using
FOLL_PIN (pin_user_page*()) page pinning.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
block/bio.c | 25 ++++++++++++-------------
block/blk-map.c | 6 +++---
fs/direct-io.c | 26 +++++++++++++-------------
fs/iomap/direct-io.c | 2 +-
4 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 4679d6539e2d..d078f992a9c9 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1102,7 +1102,7 @@ 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);
+ unpin_user_page(bvec->bv_page);
}
}
EXPORT_SYMBOL_GPL(__bio_release_pages);
@@ -1130,10 +1130,9 @@ void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)

static void bio_put_pages(struct page **pages, size_t size, size_t off)
{
- size_t i, nr = DIV_ROUND_UP(size + (off & ~PAGE_MASK), PAGE_SIZE);
+ size_t nr = DIV_ROUND_UP(size + (off & ~PAGE_MASK), PAGE_SIZE);

- for (i = 0; i < nr; i++)
- put_page(pages[i]);
+ unpin_user_pages(pages, nr);
}

#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
@@ -1144,9 +1143,9 @@ static void bio_put_pages(struct page **pages, size_t size, size_t off)
* @iter: iov iterator describing the region to be mapped
*
* Pins pages from *iter and appends them to @bio's bvec array. The
- * pages will have to be released using put_page() when done.
- * For multi-segment *iter, this function only adds pages from the
- * next non-empty segment of the iov iterator.
+ * pages will have to be released using unpin_user_page() when done. For
+ * multi-segment *iter, this function only adds pages from the next non-empty
+ * segment of the iov iterator.
*/
static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
{
@@ -1169,7 +1168,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)

WARN_ON_ONCE(!iter_is_iovec(iter));

- size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
+ size = iov_iter_pin_pages(iter, pages, LONG_MAX, nr_pages, &offset);
if (unlikely(size <= 0))
return size ? size : -EFAULT;

@@ -1180,7 +1179,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)

if (__bio_try_merge_page(bio, page, len, offset, &same_page)) {
if (same_page)
- put_page(page);
+ unpin_user_page(page);
} else {
if (WARN_ON_ONCE(bio_full(bio, len))) {
bio_put_pages(pages + i, left, offset);
@@ -1221,7 +1220,7 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)

WARN_ON_ONCE(!iter_is_iovec(iter));

- size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
+ size = iov_iter_pin_pages(iter, pages, LONG_MAX, nr_pages, &offset);
if (unlikely(size <= 0))
return size ? size : -EFAULT;

@@ -1237,7 +1236,7 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
break;
}
if (same_page)
- put_page(page);
+ unpin_user_page(page);
offset = 0;
}

@@ -1434,8 +1433,8 @@ 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 run one unpin_user_page() against 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-map.c b/block/blk-map.c
index c7f71d83eff1..ce450683994c 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -252,7 +252,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
size_t offs, added = 0;
int npages;

- bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
+ bytes = iov_iter_pin_pages_alloc(iter, &pages, LONG_MAX, &offs);
if (unlikely(bytes <= 0)) {
ret = bytes ? bytes : -EFAULT;
goto out_unmap;
@@ -275,7 +275,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
if (!bio_add_hw_page(rq->q, bio, page, n, offs,
max_sectors, &same_page)) {
if (same_page)
- put_page(page);
+ unpin_user_page(page);
break;
}

@@ -289,7 +289,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
* release the pages we didn't map into the bio, if any
*/
while (j < npages)
- put_page(pages[j++]);
+ unpin_user_page(pages[j++]);
kvfree(pages);
/* couldn't stuff something into bio? */
if (bytes)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 7dbbbfef300d..815407c26f57 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -171,7 +171,7 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)

WARN_ON_ONCE(!iter_is_iovec(sdio->iter));

- ret = iov_iter_get_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES,
+ ret = iov_iter_pin_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES,
&sdio->from);

if (ret < 0 && sdio->blocks_available && (dio->op == REQ_OP_WRITE)) {
@@ -183,7 +183,7 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
*/
if (dio->page_errors == 0)
dio->page_errors = ret;
- get_page(page);
+ pin_user_page(page);
dio->pages[0] = page;
sdio->head = 0;
sdio->tail = 1;
@@ -452,7 +452,7 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio)
{
while (sdio->head < sdio->tail)
- put_page(dio->pages[sdio->head++]);
+ unpin_user_page(dio->pages[sdio->head++]);
}

/*
@@ -717,7 +717,7 @@ static inline int dio_bio_add_page(struct dio_submit *sdio)
*/
if ((sdio->cur_page_len + sdio->cur_page_offset) == PAGE_SIZE)
sdio->pages_in_io--;
- get_page(sdio->cur_page);
+ pin_user_page(sdio->cur_page);
sdio->final_block_in_bio = sdio->cur_page_block +
(sdio->cur_page_len >> sdio->blkbits);
ret = 0;
@@ -832,13 +832,13 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page,
*/
if (sdio->cur_page) {
ret = dio_send_cur_page(dio, sdio, map_bh);
- put_page(sdio->cur_page);
+ unpin_user_page(sdio->cur_page);
sdio->cur_page = NULL;
if (ret)
return ret;
}

- get_page(page); /* It is in dio */
+ pin_user_page(page); /* It is in dio */
sdio->cur_page = page;
sdio->cur_page_offset = offset;
sdio->cur_page_len = len;
@@ -853,7 +853,7 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page,
ret = dio_send_cur_page(dio, sdio, map_bh);
if (sdio->bio)
dio_bio_submit(dio, sdio);
- put_page(sdio->cur_page);
+ unpin_user_page(sdio->cur_page);
sdio->cur_page = NULL;
}
return ret;
@@ -953,7 +953,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,

ret = get_more_blocks(dio, sdio, map_bh);
if (ret) {
- put_page(page);
+ unpin_user_page(page);
goto out;
}
if (!buffer_mapped(map_bh))
@@ -998,7 +998,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,

/* AKPM: eargh, -ENOTBLK is a hack */
if (dio->op == REQ_OP_WRITE) {
- put_page(page);
+ unpin_user_page(page);
return -ENOTBLK;
}

@@ -1011,7 +1011,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
if (sdio->block_in_file >=
i_size_aligned >> blkbits) {
/* We hit eof */
- put_page(page);
+ unpin_user_page(page);
goto out;
}
zero_user(page, from, 1 << blkbits);
@@ -1051,7 +1051,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
sdio->next_block_for_io,
map_bh);
if (ret) {
- put_page(page);
+ unpin_user_page(page);
goto out;
}
sdio->next_block_for_io += this_chunk_blocks;
@@ -1067,7 +1067,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
}

/* Drop the ref which was taken in get_user_pages() */
- put_page(page);
+ unpin_user_page(page);
}
out:
return ret;
@@ -1289,7 +1289,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
ret2 = dio_send_cur_page(dio, &sdio, &map_bh);
if (retval == 0)
retval = ret2;
- put_page(sdio.cur_page);
+ unpin_user_page(sdio.cur_page);
sdio.cur_page = NULL;
}
if (sdio.bio)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 67cf9c16f80c..d0986a31a9d1 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -192,7 +192,7 @@ static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio,
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;

- get_page(page);
+ pin_user_page(page);
__bio_add_page(bio, page, len, 0);
iomap_dio_submit_bio(iter, dio, bio, pos);
}
--
2.35.1