Re: [PATCH 4/4] mm: Remove get_kernel_pages()

From: John Hubbard
Date: Mon Oct 03 2022 - 16:29:23 EST


On 10/1/22 17:23, ira.weiny@xxxxxxxxx wrote:
From: Ira Weiny <ira.weiny@xxxxxxxxx>

The only caller to get_kernel_pages() [shm_get_kernel_pages()] has been
updated to not need it.

Remove get_kernel_pages().

Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: "Fabio M. De Francesco" <fmdefrancesco@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
include/linux/mm.h | 2 --
mm/swap.c | 30 ------------------------------
2 files changed, 32 deletions(-)


Good to see this removed (including the EXPORT), even if the
functionality still remains in a less obvious form, over in shm.

The fewer "all your page are pinned" calls we need, the simpler things
get. :)


Acked-by: John Hubbard <jhubbard@xxxxxxxxxx>

thanks,
--
John Hubbard
NVIDIA

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8bbcccbc5565..9a06df4f057c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1969,8 +1969,6 @@ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
struct task_struct *task, bool bypass_rlim);
struct kvec;
-int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
- struct page **pages);
struct page *get_dump_page(unsigned long addr);
bool folio_mark_dirty(struct folio *folio);
diff --git a/mm/swap.c b/mm/swap.c
index 955930f41d20..a9aa648eb0d0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -157,36 +157,6 @@ void put_pages_list(struct list_head *pages)
}
EXPORT_SYMBOL(put_pages_list);
-/*
- * get_kernel_pages() - pin kernel pages in memory
- * @kiov: An array of struct kvec structures
- * @nr_segs: number of segments to pin
- * @write: pinning for read/write, currently ignored
- * @pages: array that receives pointers to the pages pinned.
- * Should be at least nr_segs long.
- *
- * Returns number of pages pinned. This may be fewer than the number requested.
- * If nr_segs is 0 or negative, returns 0. If no pages were pinned, returns 0.
- * Each page returned must be released with a put_page() call when it is
- * finished with.
- */
-int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
- struct page **pages)
-{
- int seg;
-
- for (seg = 0; seg < nr_segs; seg++) {
- if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
- return seg;
-
- pages[seg] = kmap_to_page(kiov[seg].iov_base);
- get_page(pages[seg]);
- }
-
- return seg;
-}
-EXPORT_SYMBOL_GPL(get_kernel_pages);
-
typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
static void lru_add_fn(struct lruvec *lruvec, struct folio *folio)