[PATCHv4 2/9] block/bio: remove duplicate append pages code

Keith Busch
2022-05-26T01:08:36Z

From: Keith Busch <kbusch@kernel.org>

The getting pages setup for zone append and normal IO are identical. Use
common code for each.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
block/bio.c | 102 ++++++++++++++++++++++------------------------------
1 file changed, 42 insertions(+), 60 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index e249f6414fd5..55d2a9c4e312 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1158,6 +1158,37 @@ static void bio_put_pages(struct page **pages, size_t size, size_t off)
put_page(pages[i]);
}

+static int bio_iov_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
+{
+ bool same_page = false;
+
+ if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
+ if (WARN_ON_ONCE(bio_full(bio, len)))
+ return -EINVAL;
+ __bio_add_page(bio, page, len, offset);
+ return 0;
+ }
+
+ if (same_page)
+ put_page(page);
+ return 0;
+}
+
+static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
+{
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+ bool same_page = false;
+
+ if (bio_add_hw_page(q, bio, page, len, offset,
+ queue_max_zone_append_sectors(q), &same_page) != len)
+ return -EINVAL;
+ if (same_page)
+ put_page(page);
+ return 0;
+}
+
#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))

/**
@@ -1176,7 +1207,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
struct page **pages = (struct page **)bv;
- bool same_page = false;
ssize_t size, left;
unsigned len, i;
size_t offset;
@@ -1185,7 +1215,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
* Move page array up in the allocated memory for the bio vecs as far as
* possible so that we can start filling biovecs from the beginning
* without overwriting the temporary page array.
- */
+ */
BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);

@@ -1195,18 +1225,18 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)

for (left = size, i = 0; left > 0; left -= len, i++) {
struct page *page = pages[i];
+ int ret;

len = min_t(size_t, PAGE_SIZE - offset, left);
+ if (bio_op(bio) == REQ_OP_ZONE_APPEND)
+ ret = bio_iov_add_zone_append_page(bio, page, len,
+ offset);
+ else
+ ret = bio_iov_add_page(bio, page, len, offset);

- if (__bio_try_merge_page(bio, page, len, offset, &same_page)) {
- if (same_page)
- put_page(page);
- } else {
- if (WARN_ON_ONCE(bio_full(bio, len))) {
- bio_put_pages(pages + i, left, offset);
- return -EINVAL;
- }
- __bio_add_page(bio, page, len, offset);
+ if (ret) {
+ bio_put_pages(pages + i, left, offset);
+ return ret;
}
offset = 0;
}
@@ -1215,51 +1245,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
return 0;
}

-static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
-{
- unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
- unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
- struct request_queue *q = bdev_get_queue(bio->bi_bdev);
- unsigned int max_append_sectors = queue_max_zone_append_sectors(q);
- struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
- struct page **pages = (struct page **)bv;
- ssize_t size, left;
- unsigned len, i;
- size_t offset;
- int ret = 0;
-
- /*
- * Move page array up in the allocated memory for the bio vecs as far as
- * possible so that we can start filling biovecs from the beginning
- * without overwriting the temporary page array.
- */
- BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
- pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
-
- size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
- if (unlikely(size <= 0))
- return size ? size : -EFAULT;
-
- for (left = size, i = 0; left > 0; left -= len, i++) {
- struct page *page = pages[i];
- bool same_page = false;
-
- len = min_t(size_t, PAGE_SIZE - offset, left);
- if (bio_add_hw_page(q, bio, page, len, offset,
- max_append_sectors, &same_page) != len) {
- bio_put_pages(pages + i, left, offset);
- ret = -EINVAL;
- break;
- }
- if (same_page)
- put_page(page);
- offset = 0;
- }
-
- iov_iter_advance(iter, size - left);
- return ret;
-}
-
/**
* bio_iov_iter_get_pages - add user or kernel pages to a bio
* @bio: bio to add pages to
@@ -1294,10 +1279,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
}

do {
- if (bio_op(bio) == REQ_OP_ZONE_APPEND)
- ret = __bio_iov_append_get_pages(bio, iter);
- else
- ret = __bio_iov_iter_get_pages(bio, iter);
+ ret = __bio_iov_iter_get_pages(bio, iter);
} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));

/* don't account direct I/O as memory stall */
--
2.30.2