From a70aae12502b130b0c30dda44dff09e575c1aaeb Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 11 Apr 2023 19:14:43 +0200 Subject: 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 Reviewed-by: Sergey Senozhatsky Cc: Jens Axboe Cc: Minchan Kim Signed-off-by: Andrew Morton --- drivers/block/zram/zram_drv.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index aa490da3cef2..57787cbdf1f7 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -148,6 +148,7 @@ static inline bool is_partial_io(struct bio_vec *bvec) { 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 zram *zram, struct bio_vec *bvec, 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) {}; -- cgit v1.2.3