diff mbox series

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

Message ID 20220227093434.2889464-5-jhubbard@nvidia.com (mailing list archive)
State New, archived
Headers show
Series block, fs: convert most Direct IO cases to FOLL_PIN | expand

Commit Message

jhubbard.send.patches@gmail.com Feb. 27, 2022, 9:34 a.m. UTC 
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(-)

Comments

Jens Axboe Feb. 27, 2022, 9:59 p.m. UTC | #1 
On 2/27/22 2:34 AM, jhubbard.send.patches@gmail.com wrote:
> 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.

The commit message needs to explain why a change is being made, not what
is being done. The latter I can just look at the code for.

Didn't even find it in in your cover letter, had to go to the original
posting for that.
John Hubbard Feb. 27, 2022, 10:13 p.m. UTC | #2 
On 2/27/22 13:59, Jens Axboe wrote:
> On 2/27/22 2:34 AM, jhubbard.send.patches@gmail.com wrote:
>> 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.
> 
> The commit message needs to explain why a change is being made, not what
> is being done. The latter I can just look at the code for.
> 
> Didn't even find it in in your cover letter, had to go to the original
> posting for that.
> 

Sorry about that, I'll sit down and write up something thorough for this
patch. It is after the central thing, and it got neglected here.

thanks,
diff mbox series

Patch

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);
 }