From aad5b23ebf21573a32b6f07644f028d64492a5d6 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 28 Mar 2022 12:34:31 -0400 Subject: [PATCH] dm: fix dm_io and dm_target_io flags race condition on Alpha Early alpha processors cannot write a single byte or short; they read 8 bytes, modify the value in registers and write back 8 bytes. This could cause race condition in the structure dm_io - if the fields flags and io_count are modified simultaneously. Fix this bug by using 32-bit flags if we are on Alpha and if we are compiling for a processor that doesn't have the byte-word-extension. Signed-off-by: Mikulas Patocka Fixes: bd4a6dd241ae ("dm: reduce size of dm_io and dm_target_io structs") [snitzer: Jens allowed this change since Mikulas owns a relevant Alpha!] Acked-by: Jens Axboe Signed-off-by: Mike Snitzer --- drivers/md/dm-core.h | 4 ++-- include/linux/blk_types.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 4081cb6..4277853 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -210,7 +210,7 @@ struct dm_table { #define DM_TIO_MAGIC 28714 struct dm_target_io { unsigned short magic; - unsigned short flags; + blk_short_t flags; unsigned int target_bio_nr; struct dm_io *io; struct dm_target *ti; @@ -244,7 +244,7 @@ static inline void dm_tio_set_flag(struct dm_target_io *tio, unsigned int bit) #define DM_IO_MAGIC 19577 struct dm_io { unsigned short magic; - unsigned short flags; + blk_short_t flags; atomic_t io_count; struct mapped_device *md; struct bio *orig_bio; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index dd0763a..1973ef9 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -85,8 +85,10 @@ struct block_device { */ #if defined(CONFIG_ALPHA) && !defined(__alpha_bwx__) typedef u32 __bitwise blk_status_t; +typedef u32 blk_short_t; #else typedef u8 __bitwise blk_status_t; +typedef u16 blk_short_t; #endif #define BLK_STS_OK 0 #define BLK_STS_NOTSUPP ((__force blk_status_t)1) -- 2.7.4