On Mon 26-02-18 20:20:11, Dan Williams wrote:
dax_sem_{up,down}_write_sem() allow the ext2 dax semaphore to be compiled out in the CONFIG_FS_DAX=n case. However there are still some open coded uses of the semaphore. Add dax_sem_{up_read,down_read,_is_locked}() helpers and convert all open-coded usages of the semaphore to the helpers.
Just one nit below. With that fixed you can add:
Reviewed-by: Jan Kara jack@suse.cz
Cc: Jan Kara jack@suse.com Cc: stable@vger.kernel.org Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Signed-off-by: Dan Williams dan.j.williams@intel.com
fs/ext2/ext2.h | 6 ++++++ fs/ext2/file.c | 5 ++--- fs/ext2/inode.c | 4 +--- 3 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h index 032295e1d386..7ceb29733cdb 100644 --- a/fs/ext2/ext2.h +++ b/fs/ext2/ext2.h @@ -711,9 +711,15 @@ struct ext2_inode_info { #ifdef CONFIG_FS_DAX #define dax_sem_down_write(ext2_inode) down_write(&(ext2_inode)->dax_sem) #define dax_sem_up_write(ext2_inode) up_write(&(ext2_inode)->dax_sem) +#define dax_sem_is_locked(ext2_inode) rwsem_is_locked(&(ext2_inode)->dax_sem) +#define dax_sem_down_read(ext2_inode) down_read(&(ext2_inode)->dax_sem) +#define dax_sem_up_read(ext2_inode) up_read(&(ext2_inode)->dax_sem) #else #define dax_sem_down_write(ext2_inode) #define dax_sem_up_write(ext2_inode) +#define dax_sem_is_locked(ext2_inode) (true)
This is a bit dangerous as depending on the use of dax_sem_is_locked() you'd need this to return true or false. E.g. assume we'd have a place where we'd like to do:
WARN_ON(dax_sem_is_locked(inode));
or just
if (dax_sem_is_locked(inode)) bail out due to congestion...
How I'd solve this is that I'd define:
#define assert_dax_sem_locked(ext2_inode) WARN_ON(rwsem_is_locked(&(ext2_inode)->dax_sem)
and just as do {} while (0) for !CONFIG_FS_DAX.
Honza