The patch titled
Subject: zram: always compile read_from_bdev_sync
has been added to the -mm mm-unstable branch. Its filename is
zram-always-compile-read_from_bdev_sync.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-always-compile-read_from_bdev_sync.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: zram: always compile read_from_bdev_sync
Date: Tue, 11 Apr 2023 19:14:43 +0200
Patch series "zram I/O path cleanups and fixups", v3.
This series cleans up the zram I/O path, and fixes the handling of
synchronous I/O to the underlying device in the writeback_store function
or for > 4K PAGE_SIZE systems.
The fixes are at the end, as I could not fully reason about them being
safe before untangling the callchain.
This patch (of 17):
read_from_bdev_sync is currently only compiled for non-4k PAGE_SIZE, which
means it won't be built with the most common configurations.
Replace the ifdef with a check for the PAGE_SIZE in an if instead. The
check uses an extra symbol and IS_ENABLED to allow the compiler to
eliminate the dead code, leading to the same generated code size:
text data bss dec hex filename
16709 1428 12 18149 46e5 drivers/block/zram/zram_drv.o.old
16709 1428 12 18149 46e5 drivers/block/zram/zram_drv.o.new
Link: https://lkml.kernel.org/r/20230411171459.567614-1-hch@xxxxxx
Link: https://lkml.kernel.org/r/20230411171459.567614-2-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-always-compile-read_from_bdev_sync
+++ a/drivers/block/zram/zram_drv.c
@@ -148,6 +148,7 @@ static inline bool is_partial_io(struct
{
return bvec->bv_len != PAGE_SIZE;
}
+#define ZRAM_PARTIAL_IO 1
#else
static inline bool is_partial_io(struct bio_vec *bvec)
{
@@ -833,7 +834,6 @@ struct zram_work {
struct bio_vec bvec;
};
-#if PAGE_SIZE != 4096
static void zram_sync_read(struct work_struct *work)
{
struct zram_work *zw = container_of(work, struct zram_work, work);
@@ -866,23 +866,17 @@ static int read_from_bdev_sync(struct zr
return 1;
}
-#else
-static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
- unsigned long entry, struct bio *bio)
-{
- WARN_ON(1);
- return -EIO;
-}
-#endif
static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *parent, bool sync)
{
atomic64_inc(&zram->stats.bd_reads);
- if (sync)
+ if (sync) {
+ if (WARN_ON_ONCE(!IS_ENABLED(ZRAM_PARTIAL_IO)))
+ return -EIO;
return read_from_bdev_sync(zram, bvec, entry, parent);
- else
- return read_from_bdev_async(zram, bvec, entry, parent);
+ }
+ return read_from_bdev_async(zram, bvec, entry, parent);
}
#else
static inline void reset_bdev(struct zram *zram) {};
_
Patches currently in -mm which might be from hch@xxxxxx are
zram-always-compile-read_from_bdev_sync.patch
zram-remove-valid_io_request.patch
zram-make-zram_bio_discard-more-self-contained.patch
zram-simplify-bvec-iteration-in-__zram_make_request.patch
zram-move-discard-handling-to-zram_submit_bio.patch
zram-return-early-on-error-in-zram_bvec_rw.patch
zram-refactor-highlevel-read-and-write-handling.patch
zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite.patch
zram-rename-__zram_bvec_read-to-zram_read_page.patch
zram-directly-call-zram_read_page-in-writeback_store.patch
zram-refactor-zram_bdev_read.patch
zram-dont-pass-a-bvec-to-__zram_bvec_write.patch
zram-refactor-zram_bdev_write.patch
zram-pass-a-page-to-read_from_bdev.patch
zram-dont-return-errors-from-read_from_bdev_async.patch
zram-fix-synchronous-reads.patch
zram-return-errors-from-read_from_bdev_sync.patch
