The patch titled
Subject: ramfs: convert ramfs_nommu_get_unmapped_area() to use filemap_get_folios_contig()
has been added to the -mm mm-unstable branch. Its filename is
ramfs-convert-ramfs_nommu_get_unmapped_area-to-use-filemap_get_folios_contig.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ramfs-convert-ramfs_nommu_get_unmapped_area-to-use-filemap_get_folios_contig.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: "Vishal Moola (Oracle)" <vishal.moola@xxxxxxxxx>
Subject: ramfs: convert ramfs_nommu_get_unmapped_area() to use filemap_get_folios_contig()
Date: Tue, 23 Aug 2022 17:40:22 -0700
Convert to use folios throughout. This is in preparation for the removal
for find_get_pages_contig(). Now also supports large folios.
The initial version of this function set the page_address to be returned
after finishing all the checks. Since folio_batches have a maximum of 15
folios, the function had to be modified to support getting and checking up
to lpages, 15 pages at a time while still returning the initial page
address. Now the function sets ret as soon as the first batch arrives,
and updates it only if a check fails.
The physical adjacency check utilizes the page frame numbers. The page
frame number of each folio must be nr_pages away from the first folio.
Link: https://lkml.kernel.org/r/20220824004023.77310-7-vishal.moola@xxxxxxxxx
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: David Sterba <dsterb@xxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ramfs/file-nommu.c | 54 ++++++++++++++++++++++------------------
1 file changed, 31 insertions(+), 23 deletions(-)
--- a/fs/ramfs/file-nommu.c~ramfs-convert-ramfs_nommu_get_unmapped_area-to-use-filemap_get_folios_contig
+++ a/fs/ramfs/file-nommu.c
@@ -203,9 +203,9 @@ static unsigned long ramfs_nommu_get_unm
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
- unsigned long maxpages, lpages, nr, loop, ret;
+ unsigned long maxpages, lpages, nr_folios, loop, ret, nr_pages, pfn;
struct inode *inode = file_inode(file);
- struct page **pages = NULL, **ptr, *page;
+ struct folio_batch fbatch;
loff_t isize;
/* the mapping mustn't extend beyond the EOF */
@@ -221,31 +221,39 @@ static unsigned long ramfs_nommu_get_unm
goto out;
/* gang-find the pages */
- pages = kcalloc(lpages, sizeof(struct page *), GFP_KERNEL);
- if (!pages)
- goto out_free;
-
- nr = find_get_pages_contig(inode->i_mapping, pgoff, lpages, pages);
- if (nr != lpages)
- goto out_free_pages; /* leave if some pages were missing */
-
+ folio_batch_init(&fbatch);
+ nr_pages = 0;
+repeat:
+ nr_folios = filemap_get_folios_contig(inode->i_mapping, &pgoff,
+ ULONG_MAX, &fbatch);
+ if (!nr_folios) {
+ ret = -ENOSYS;
+ return ret;
+ }
+
+ if (ret == -ENOSYS) {
+ ret = (unsigned long) folio_address(fbatch.folios[0]);
+ pfn = folio_pfn(fbatch.folios[0]);
+ }
/* check the pages for physical adjacency */
- ptr = pages;
- page = *ptr++;
- page++;
- for (loop = lpages; loop > 1; loop--)
- if (*ptr++ != page++)
- goto out_free_pages;
-
+ for (loop = 0; loop < nr_folios; loop++) {
+ if (pfn + nr_pages != folio_pfn(fbatch.folios[loop])) {
+ ret = -ENOSYS;
+ goto out_free; /* leave if not physical adjacent */
+ }
+ nr_pages += folio_nr_pages(fbatch.folios[loop]);
+ if (nr_pages >= lpages)
+ goto out_free; /* successfully found desired pages*/
+ }
+
+ if (nr_pages < lpages) {
+ folio_batch_release(&fbatch);
+ goto repeat; /* loop if pages are missing */
+ }
/* okay - all conditions fulfilled */
- ret = (unsigned long) page_address(pages[0]);
-out_free_pages:
- ptr = pages;
- for (loop = nr; loop > 0; loop--)
- put_page(*ptr++);
out_free:
- kfree(pages);
+ folio_batch_release(&fbatch);
out:
return ret;
}
_
Patches currently in -mm which might be from vishal.moola@xxxxxxxxx are
filemap-add-filemap_get_folios_contig.patch
btrfs-convert-__process_pages_contig-to-use-filemap_get_folios_contig.patch
btrfs-convert-end_compressed_writeback-to-use-filemap_get_folios.patch
btrfs-convert-process_page_range-to-use-filemap_get_folios_contig.patch
nilfs2-convert-nilfs_find_uncommited_extent-to-use-filemap_get_folios_contig.patch
ramfs-convert-ramfs_nommu_get_unmapped_area-to-use-filemap_get_folios_contig.patch
filemap-remove-find_get_pages_contig.patch
