+ filemap-add-mapping_read_folio_gfp.patch added to mm-unstable branch

+ filemap-add-mapping_read_folio_gfp.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: filemap: add mapping_read_folio_gfp()
has been added to the -mm mm-unstable branch.  Its filename is
     filemap-add-mapping_read_folio_gfp.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/filemap-add-mapping_read_folio_gfp.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: filemap: add mapping_read_folio_gfp()
Date: Mon, 6 Feb 2023 16:25:19 +0000

This is like read_cache_page_gfp() except it returns the folio instead
of the precise page.

Link: https://lkml.kernel.org/r/20230206162520.4029022-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mark Hemment <markhemm@googlemail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/include/linux/pagemap.h~filemap-add-mapping_read_folio_gfp
+++ a/include/linux/pagemap.h
@@ -756,6 +756,8 @@ static inline struct page *grab_cache_pa
 
 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
 		filler_t *filler, struct file *file);
+struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
+		gfp_t flags);
 struct page *read_cache_page(struct address_space *, pgoff_t index,
 		filler_t *filler, struct file *file);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
--- a/mm/filemap.c~filemap-add-mapping_read_folio_gfp
+++ a/mm/filemap.c
@@ -3585,6 +3585,30 @@ struct folio *read_cache_folio(struct ad
 }
 EXPORT_SYMBOL(read_cache_folio);
 
+/**
+ * mapping_read_folio_gfp - Read into page cache, using specified allocation flags.
+ * @mapping:	The address_space for the folio.
+ * @index:	The index that the allocated folio will contain.
+ * @gfp:	The page allocator flags to use if allocating.
+ *
+ * This is the same as "read_cache_folio(mapping, index, NULL, NULL)", but with
+ * any new memory allocations done using the specified allocation flags.
+ *
+ * The most likely error from this function is EIO, but ENOMEM is
+ * possible and so is EINTR.  If ->read_folio returns another error,
+ * that will be returned to the caller.
+ *
+ * The function expects mapping->invalidate_lock to be already held.
+ *
+ * Return: Uptodate folio on success, ERR_PTR() on failure.
+ */
+struct folio *mapping_read_folio_gfp(struct address_space *mapping,
+		pgoff_t index, gfp_t gfp)
+{
+	return do_read_cache_folio(mapping, index, NULL, NULL, gfp);
+}
+EXPORT_SYMBOL(mapping_read_folio_gfp);
+
 static struct page *do_read_cache_page(struct address_space *mapping,
 		pgoff_t index, filler_t *filler, struct file *file, gfp_t gfp)
 {
_

Patches currently in -mm which might be from willy@infradead.org are

mm-add-memcpy_from_file_folio.patch
filemap-add-mapping_read_folio_gfp.patch
shmem-add-shmem_read_folio-and-shmem_read_folio_gfp.patch
shmem-fix-w=1-build-warnings-with-config_shmem=n.patch