[PATCH v4 12/12] iomap: Convert from readpages to readahead
From: Matthew Wilcox
Date: Sat Feb 01 2020 - 10:13:20 EST
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Use the new readahead operation in XFS and iomap.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: linux-xfs@xxxxxxxxxxxxxxx
---
fs/iomap/buffered-io.c | 72 +++++++++---------------------------------
fs/iomap/trace.h | 2 +-
fs/xfs/xfs_aops.c | 10 +++---
include/linux/iomap.h | 2 +-
4 files changed, 22 insertions(+), 64 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index cb3511eb152a..490b66ea3298 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -216,7 +216,6 @@ struct iomap_readpage_ctx {
bool cur_page_in_bio;
bool is_readahead;
struct bio *bio;
- struct list_head *pages;
};
static void
@@ -367,36 +366,8 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops)
}
EXPORT_SYMBOL_GPL(iomap_readpage);
-static struct page *
-iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
- loff_t length, loff_t *done)
-{
- while (!list_empty(pages)) {
- struct page *page = lru_to_page(pages);
-
- if (page_offset(page) >= (u64)pos + length)
- break;
-
- list_del(&page->lru);
- if (!add_to_page_cache_lru(page, inode->i_mapping, page->index,
- GFP_NOFS))
- return page;
-
- /*
- * If we already have a page in the page cache at index we are
- * done. Upper layers don't care if it is uptodate after the
- * readpages call itself as every page gets checked again once
- * actually needed.
- */
- *done += PAGE_SIZE;
- put_page(page);
- }
-
- return NULL;
-}
-
static loff_t
-iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
+iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
void *data, struct iomap *iomap, struct iomap *srcmap)
{
struct iomap_readpage_ctx *ctx = data;
@@ -410,10 +381,8 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
ctx->cur_page = NULL;
}
if (!ctx->cur_page) {
- ctx->cur_page = iomap_next_page(inode, ctx->pages,
- pos, length, &done);
- if (!ctx->cur_page)
- break;
+ ctx->cur_page = readahead_page(inode->i_mapping,
+ pos / PAGE_SIZE);
ctx->cur_page_in_bio = false;
}
ret = iomap_readpage_actor(inode, pos + done, length - done,
@@ -423,48 +392,37 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
return done;
}
-int
-iomap_readpages(struct address_space *mapping, struct list_head *pages,
+unsigned
+iomap_readahead(struct address_space *mapping, pgoff_t start,
unsigned nr_pages, const struct iomap_ops *ops)
{
struct iomap_readpage_ctx ctx = {
- .pages = pages,
.is_readahead = true,
};
- loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
- loff_t last = page_offset(list_entry(pages->next, struct page, lru));
- loff_t length = last - pos + PAGE_SIZE, ret = 0;
+ loff_t pos = start * PAGE_SIZE;
+ loff_t length = nr_pages * PAGE_SIZE;
- trace_iomap_readpages(mapping->host, nr_pages);
+ trace_iomap_readahead(mapping->host, nr_pages);
while (length > 0) {
- ret = iomap_apply(mapping->host, pos, length, 0, ops,
- &ctx, iomap_readpages_actor);
+ loff_t ret = iomap_apply(mapping->host, pos, length, 0, ops,
+ &ctx, iomap_readahead_actor);
if (ret <= 0) {
WARN_ON_ONCE(ret == 0);
- goto done;
+ break;
}
pos += ret;
length -= ret;
}
- ret = 0;
-done:
+
if (ctx.bio)
submit_bio(ctx.bio);
- if (ctx.cur_page) {
- if (!ctx.cur_page_in_bio)
- unlock_page(ctx.cur_page);
+ if (ctx.cur_page && ctx.cur_page_in_bio)
put_page(ctx.cur_page);
- }
- /*
- * Check that we didn't lose a page due to the arcance calling
- * conventions..
- */
- WARN_ON_ONCE(!ret && !list_empty(ctx.pages));
- return ret;
+ return length / PAGE_SIZE;
}
-EXPORT_SYMBOL_GPL(iomap_readpages);
+EXPORT_SYMBOL_GPL(iomap_readahead);
/*
* iomap_is_partially_uptodate checks whether blocks within a page are
diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h
index 6dc227b8c47e..d6ba705f938a 100644
--- a/fs/iomap/trace.h
+++ b/fs/iomap/trace.h
@@ -39,7 +39,7 @@ DEFINE_EVENT(iomap_readpage_class, name, \
TP_PROTO(struct inode *inode, int nr_pages), \
TP_ARGS(inode, nr_pages))
DEFINE_READPAGE_EVENT(iomap_readpage);
-DEFINE_READPAGE_EVENT(iomap_readpages);
+DEFINE_READPAGE_EVENT(iomap_readahead);
DECLARE_EVENT_CLASS(iomap_page_class,
TP_PROTO(struct inode *inode, struct page *page, unsigned long off,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 3a688eb5c5ae..4d9da34e759b 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -621,14 +621,14 @@ xfs_vm_readpage(
return iomap_readpage(page, &xfs_read_iomap_ops);
}
-STATIC int
-xfs_vm_readpages(
+STATIC unsigned
+xfs_vm_readahead(
struct file *unused,
struct address_space *mapping,
- struct list_head *pages,
+ pgoff_t start,
unsigned nr_pages)
{
- return iomap_readpages(mapping, pages, nr_pages, &xfs_read_iomap_ops);
+ return iomap_readahead(mapping, start, nr_pages, &xfs_read_iomap_ops);
}
static int
@@ -644,7 +644,7 @@ xfs_iomap_swapfile_activate(
const struct address_space_operations xfs_address_space_operations = {
.readpage = xfs_vm_readpage,
- .readpages = xfs_vm_readpages,
+ .readahead = xfs_vm_readahead,
.writepage = xfs_vm_writepage,
.writepages = xfs_vm_writepages,
.set_page_dirty = iomap_set_page_dirty,
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 8b09463dae0d..81c6067e9b61 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -155,7 +155,7 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
int iomap_readpage(struct page *page, const struct iomap_ops *ops);
-int iomap_readpages(struct address_space *mapping, struct list_head *pages,
+unsigned iomap_readahead(struct address_space *, pgoff_t start,
unsigned nr_pages, const struct iomap_ops *ops);
int iomap_set_page_dirty(struct page *page);
int iomap_is_partially_uptodate(struct page *page, unsigned long from,
--
2.24.1