On Thu, Mar 25, 2021 at 03:31:42PM -0400, Gabriel Krisman Bertazi wrote: > Eric Biggers <ebiggers@xxxxxxxxxx> writes: > > > On Thu, Mar 25, 2021 at 05:38:08AM +0530, Shreeya Patel wrote: > >> utf8_unload is being called if CONFIG_UNICODE is enabled. > >> The ifdef block doesn't check if utf8 encoding has been loaded > >> or not before calling the utf8_unload() function. > >> This is not the expected behavior since it would sometimes lead > >> to unloading utf8 even before loading it. > >> Hence, add a condition which will check if sb->encoding is NOT NULL > >> before calling the utf8_unload(). > >> > >> Reviewed-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> > >> Signed-off-by: Shreeya Patel <shreeya.patel@xxxxxxxxxxxxx> > >> --- > >> fs/ext4/super.c | 6 ++++-- > >> fs/f2fs/super.c | 9 ++++++--- > >> 2 files changed, 10 insertions(+), 5 deletions(-) > >> > >> diff --git a/fs/ext4/super.c b/fs/ext4/super.c > >> index ad34a37278cd..e438d14f9a87 100644 > >> --- a/fs/ext4/super.c > >> +++ b/fs/ext4/super.c > >> @@ -1259,7 +1259,8 @@ static void ext4_put_super(struct super_block *sb) > >> fs_put_dax(sbi->s_daxdev); > >> fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy); > >> #ifdef CONFIG_UNICODE > >> - utf8_unload(sb->s_encoding); > >> + if (sb->s_encoding) > >> + utf8_unload(sb->s_encoding); > >> #endif > >> kfree(sbi); > >> } > > > > > > What's the benefit of this change? utf8_unload is a no-op when passed a NULL > > pointer; why not keep it that way? > > For the record, it no longer is a no-op after patch 5 of this series. > Honestly, I prefer making it explicitly at the caller that we are not > entering the function, like the patch does, instead of returning from it > immediately. Makes it more readable, IMO. > I don't think making all the callers do the NULL check is more readable. It's conventional for free-like functions to accept NULL pointers. See for example every other function in the code snippet above -- fs_put_dax(), fscrypt_free_dummy_policy(), and kfree(). This seems more like an issue with patch 5; it shouldn't be dropping the NULL check from unicode_unload(). - Eric
