[PATCH 01/14] iomap: add wrapper to pass readpage_ctx to read path

Andrey Albershteyn
2024-12-29T13:38:54Z

Make filesystems able to create readpage context, similar as
iomap_writepage_ctx in write path. This will allow filesystem to
pass _ops to iomap for ioend configuration (->prepare_ioend) which
in turn can be used to set BIO end callout (bio->bi_end_io).

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
---
fs/iomap/buffered-io.c | 76 ++++++++++++++++++++++++------------------
include/linux/iomap.h | 12 +++++++
2 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 0f33ac975209..0d9291719d75 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -320,14 +320,6 @@ static void iomap_read_end_io(struct bio *bio)
bio_put(bio);
}

-struct iomap_readpage_ctx {
- struct folio *cur_folio;
- bool cur_folio_in_bio;
- struct bio *bio;
- struct readahead_control *rac;
- int flags;
-};
-
/**
* iomap_read_inline_data - copy inline data into the page cache
* @iter: iteration structure
@@ -461,28 +453,27 @@ static loff_t iomap_read_folio_iter(const struct iomap_iter *iter,
return done;
}

-int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
+int iomap_read_folio_ctx(struct iomap_readpage_ctx *ctx,
+ const struct iomap_ops *ops)
{
+ struct folio *folio = ctx->cur_folio;
struct iomap_iter iter = {
.inode = folio->mapping->host,
.pos = folio_pos(folio),
.len = folio_size(folio),
};
- struct iomap_readpage_ctx ctx = {
- .cur_folio = folio,
- };
int ret;

trace_iomap_readpage(iter.inode, 1);

while ((ret = iomap_iter(&iter, ops)) > 0)
- iter.processed = iomap_read_folio_iter(&iter, &ctx);
+ iter.processed = iomap_read_folio_iter(&iter, ctx);

- if (ctx.bio) {
- submit_bio(ctx.bio);
- WARN_ON_ONCE(!ctx.cur_folio_in_bio);
+ if (ctx->bio) {
+ submit_bio(ctx->bio);
+ WARN_ON_ONCE(!ctx->cur_folio_in_bio);
} else {
- WARN_ON_ONCE(ctx.cur_folio_in_bio);
+ WARN_ON_ONCE(ctx->cur_folio_in_bio);
folio_unlock(folio);
}

@@ -493,6 +484,16 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
*/
return 0;
}
+EXPORT_SYMBOL_GPL(iomap_read_folio_ctx);
+
+int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
+{
+ struct iomap_readpage_ctx ctx = {
+ .cur_folio = folio,
+ };
+
+ return iomap_read_folio_ctx(&ctx, ops);
+}
EXPORT_SYMBOL_GPL(iomap_read_folio);

static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
@@ -520,6 +521,30 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
return done;
}

+void iomap_readahead_ctx(struct iomap_readpage_ctx *ctx,
+ const struct iomap_ops *ops)
+{
+ struct readahead_control *rac = ctx->rac;
+ struct iomap_iter iter = {
+ .inode = rac->mapping->host,
+ .pos = readahead_pos(rac),
+ .len = readahead_length(rac),
+ };
+
+ trace_iomap_readahead(rac->mapping->host, readahead_count(rac));
+
+ while (iomap_iter(&iter, ops) > 0)
+ iter.processed = iomap_readahead_iter(&iter, ctx);
+
+ if (ctx->bio)
+ submit_bio(ctx->bio);
+ if (ctx->cur_folio) {
+ if (!ctx->cur_folio_in_bio)
+ folio_unlock(ctx->cur_folio);
+ }
+}
+EXPORT_SYMBOL_GPL(iomap_readahead_ctx);
+
/**
* iomap_readahead - Attempt to read pages from a file.
* @rac: Describes the pages to be read.
@@ -537,26 +562,11 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
*/
void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
{
- struct iomap_iter iter = {
- .inode = rac->mapping->host,
- .pos = readahead_pos(rac),
- .len = readahead_length(rac),
- };
struct iomap_readpage_ctx ctx = {
.rac = rac,
};

- trace_iomap_readahead(rac->mapping->host, readahead_count(rac));
-
- while (iomap_iter(&iter, ops) > 0)
- iter.processed = iomap_readahead_iter(&iter, &ctx);
-
- if (ctx.bio)
- submit_bio(ctx.bio);
- if (ctx.cur_folio) {
- if (!ctx.cur_folio_in_bio)
- folio_unlock(ctx.cur_folio);
- }
+ iomap_readahead_ctx(&ctx, ops);
}
EXPORT_SYMBOL_GPL(iomap_readahead);

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 3297ed36c26b..b5ae08955c87 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -296,9 +296,21 @@ static inline bool iomap_want_unshare_iter(const struct iomap_iter *iter)
iter->srcmap.type == IOMAP_MAPPED;
}

+struct iomap_readpage_ctx {
+ struct folio *cur_folio;
+ bool cur_folio_in_bio;
+ struct bio *bio;
+ struct readahead_control *rac;
+ int flags;
+};
+
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops, void *private);
+int iomap_read_folio_ctx(struct iomap_readpage_ctx *ctx,
+ const struct iomap_ops *ops);
int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
+void iomap_readahead_ctx(struct iomap_readpage_ctx *ctx,
+ const struct iomap_ops *ops);
void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);
--
2.47.0