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-rw-r--r--include/linux/pagemap.h2
-rw-r--r--mm/filemap.c5
2 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d53c49abead6..47bfc6b1b632 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -710,6 +710,7 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping,
* * %FGP_NOFS - __GFP_FS will get cleared in gfp.
* * %FGP_NOWAIT - Don't block on the folio lock.
* * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
+ * * %FGP_DONTCACHE - Uncached buffered IO
* * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
* implementation.
*/
@@ -723,6 +724,7 @@ typedef unsigned int __bitwise fgf_t;
#define FGP_NOWAIT ((__force fgf_t)0x00000020)
#define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
#define FGP_STABLE ((__force fgf_t)0x00000080)
+#define FGP_DONTCACHE ((__force fgf_t)0x00000100)
#define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
#define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
diff --git a/mm/filemap.c b/mm/filemap.c
index 0aa3861aed45..279959cf9300 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1973,6 +1973,8 @@ no_page:
/* Init accessed so avoid atomic mark_page_accessed later */
if (fgp_flags & FGP_ACCESSED)
__folio_set_referenced(folio);
+ if (fgp_flags & FGP_DONTCACHE)
+ __folio_set_dropbehind(folio);
err = filemap_add_folio(mapping, folio, index, gfp);
if (!err)
@@ -1995,6 +1997,9 @@ no_page:
if (!folio)
return ERR_PTR(-ENOENT);
+ /* not an uncached lookup, clear uncached if set */
+ if (folio_test_dropbehind(folio) && !(fgp_flags & FGP_DONTCACHE))
+ folio_clear_dropbehind(folio);
return folio;
}
EXPORT_SYMBOL(__filemap_get_folio);