The patch titled
Subject: mpage: stop using bdev_{read,write}_page
has been added to the -mm mm-unstable branch. Its filename is
mpage-stop-using-bdev_readwrite_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mpage-stop-using-bdev_readwrite_page.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: Christoph Hellwig <hch@xxxxxx>
Subject: mpage: stop using bdev_{read,write}_page
Date: Wed, 25 Jan 2023 14:34:30 +0100
Patch series "remove ->rw_page".
This series removes the ->rw_page block_device_operation, which is an old
and clumsy attempt at a simple read/write fast path for the block layer.
It isn't actually used by the fastest block layer operations that we
support (polled I/O through io_uring), but only used by the mpage buffered
I/O helpers which are some of the slowest I/O we have and do not make any
difference there at all, and zram which is a block device abused to
duplicate the zram functionality.
Given that zram is heavily used we need to make sure there is a good
replacement for synchronous I/O, so this series adds a new flag for
drivers that complete I/O synchronously and uses that flag to use on-stack
bios and synchronous submission for them in the swap code.
This patch (of 7):
These are micro-optimizations for synchronous I/O, which do not matter
compared to all the other inefficiencies in the legacy buffer_head based
mpage code.
Link: https://lkml.kernel.org/r/20230125133436.447864-1-hch@xxxxxx
Link: https://lkml.kernel.org/r/20230125133436.447864-2-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Keith Busch <kbusch@xxxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/fs/mpage.c~mpage-stop-using-bdev_readwrite_page
+++ a/fs/mpage.c
@@ -269,11 +269,6 @@ static struct bio *do_mpage_readpage(str
alloc_new:
if (args->bio == NULL) {
- if (first_hole == blocks_per_page) {
- if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
- &folio->page))
- goto out;
- }
args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), opf,
gfp);
if (args->bio == NULL)
@@ -585,11 +580,6 @@ page_is_mapped:
alloc_new:
if (bio == NULL) {
- if (first_unmapped == blocks_per_page) {
- if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
- page, wbc))
- goto out;
- }
bio = bio_alloc(bdev, BIO_MAX_VECS,
REQ_OP_WRITE | wbc_to_write_flags(wbc),
GFP_NOFS);
_
Patches currently in -mm which might be from hch@xxxxxx are
revert-remoteproc-qcom_q6v5_mss-map-unmap-metadata-region-before-after-use.patch
mm-reject-vmap-with-vm_flush_reset_perms.patch
mm-remove-__vfree.patch
mm-remove-__vfree_deferred.patch
mm-move-vmalloc_init-and-free_work-down-in-vmallocc.patch
mm-call-vfree-instead-of-__vunmap-from-delayed_vfree_work.patch
mm-move-__remove_vm_area-out-of-va_remove_mappings.patch
mm-use-remove_vm_area-in-__vunmap.patch
mm-move-debug-checks-from-__vunmap-to-remove_vm_area.patch
mm-split-__vunmap.patch
mm-refactor-va_remove_mappings.patch
mpage-stop-using-bdev_readwrite_page.patch
mm-remove-the-swap_readpage-return-value.patch
mm-factor-out-a-swap_readpage_bdev-helper.patch
mm-use-an-on-stack-bio-for-synchronous-swapin.patch
mm-remove-the-__swap_writepage-return-value.patch
mm-factor-out-a-swap_writepage_bdev-helper.patch
block-remove-rw_page.patch
