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zram: always compile read_from_bdev_sync 

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@lst.de
Link: https://lkml.kernel.org/r/20230411171459.567614-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Christoph Hellwig 2023-04-11 19:14:43 +02:00 committed by Andrew Morton
parent 3b7939c8e5
commit a70aae1250
1 changed files with 6 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/block/zram/zram_drv.c
View File

@ -148,6 +148,7 @@ static inline bool is_partial_io(struct bio_vec *bvec)
{ {
return bvec->bv_len != PAGE_SIZE; return bvec->bv_len != PAGE_SIZE;
} }
#define ZRAM_PARTIAL_IO 1
#else #else
static inline bool is_partial_io(struct bio_vec *bvec) static inline bool is_partial_io(struct bio_vec *bvec)
{ {
@ -833,7 +834,6 @@ struct zram_work {
struct bio_vec bvec; struct bio_vec bvec;
}; };
#if PAGE_SIZE != 4096
static void zram_sync_read(struct work_struct *work) static void zram_sync_read(struct work_struct *work)
{ {
struct zram_work *zw = container_of(work, struct zram_work, work); struct zram_work *zw = container_of(work, struct zram_work, work);
@ -866,23 +866,17 @@ static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
return 1; 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, static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *parent, bool sync) unsigned long entry, struct bio *parent, bool sync)
{ {
atomic64_inc(&zram->stats.bd_reads); 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); 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 #else
static inline void reset_bdev(struct zram *zram) {}; static inline void reset_bdev(struct zram *zram) {};