Since commit 67f9fd91, the code to wait for the read to complete has
been dead.  That commit wrongly stated that the read was synchronous
already; this seems to have been a confusion about which ->readpage
operation was being called.  Instead of reintroducing an asynchronous
version of read_mapping_page(), call the readahead code directly to
submit all reads first before waiting for them in read_mapping_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Remove the open-coding of filemap_fdatawait_range().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If a page can't be written back, we need to call mapping_set_error(),
not clear the page's Uptodate flag.  Also remove the clearing of PageError
on success; that flag is used for read errors, not write errors.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Since we actually know what error happened, we can report it instead
of having the generic code return -EIO for pages that were unlocked
without being marked uptodate.  Also remove a test of PageError since
we have the return value at this point.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

We can cache this information in a local variable instead of communicating
from one part of the function to another via folio flags.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

The pagecache handles readpage failing by itself; it doesn't want
filesystems to remove pages from under it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If a buffer is completed with an error, its uptodate flag will be clear,
so the page_uptodate variable will have been set to 0.  There's no
need to check PageError here.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

The page cache clears the error bit before calling ->read_folio(),
so this condition could never have been true.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Just because there has been a read error doesn't mean we should avoid
marking this part of the folio as uptodate.  Indeed, it may overwrite
the error part of the folio and let us mark the entire folio uptodate.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Pages returned from read_mapping_page() are always uptodate, so
this check is unnecessary.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

read_mapping_folio() returns an ERR_PTR if the folio is not
uptodate, so this check is simply dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not
a page with PageError set, or a page that is not Uptodate, so this is
dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this test is not needed.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this test is not needed.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If read_mapping_page() sees a page with PageError set, it returns a
PTR_ERR().  Checking PageError again is simply dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Add information on the use of 'file', whether ->read_folio should be
synchronous, and steer new callers towards calling read_mapping_folio()
instead of calling ->read_folio directly.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

By passing ->read_folio to filemap_read_folio(), we can use
filemap_read_folio() in do_read_cache_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

If the call to filler() returns AOP_TRUNCATED_PAGE, we need to
retry the page cache lookup.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

No functionality change intended; this simply moves code around to
disentangle the function a little.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

The 'extern' keyword is not necessary and removing it lets us shorten
some lines.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

All callers of find_get_pages_range(), pagevec_lookup_range() and
pagevec_lookup() have now been removed.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

This is a straightforward conversion.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Change the guts of check_move_unevictable_pages() over to use folios
and add check_move_unevictable_pages() as a wrapper.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Use folios throughout.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Use folios throughout this function.  That removes the last caller of
huge_pagevec_release(), so delete that too.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Convert this function to use folios throughout.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Chao Yu <chao@kernel.org>

The called functions all use pages, so just convert back to a page.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

If the folio is large, it may overlap the beginning or end of the
unused range.  If it does, we need to avoid invalidating it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Use a folio throughout this function.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

This is the equivalent of find_get_pages() but fills a folio_batch
instead of an array of pages.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>

These functions have no more users, so delete them.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>

Remove the last caller of add_to_page_cache()
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>