From mboxrd@z Thu Jan 1 00:00:00 1970 From: Elise Lennion Date: Sun, 23 Oct 2016 00:21:00 -0000 Subject: [lustre-devel] [PATCH] staging: lustre: Move assignments out of function calls. In-Reply-To: <9F8D3E74-59D6-443A-A4A5-33C8A5D9C613@intel.com> References: <20161021221431.GA18524@lennorien.com> <9F8D3E74-59D6-443A-A4A5-33C8A5D9C613@intel.com> Message-ID: <20161023002052.GA22856@lennorien.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org On Fri, Oct 21, 2016 at 10:34:53PM +0000, Dilger, Andreas wrote: > On Oct 21, 2016, at 16:14, Elise Lennion wrote: > > > > Assignments inside of function calls confuse the reader and should be > > avoided, so they were moved out before the call. > > Thanks for your patch. I agree that this kind of usage is bad and avoid > it in my own code and try to remove it when I see it. However, in some > cases it is needed to simplify the code flow (e.g. in conditionals that > would otherwise need to duplicate logic). > > More comments below. > > > Found with Coccinelle, semantic patch: > > @@ > > identifier f; > > expression e1, e2; > > assignment operator a; > > @@ > > > > + e1 a e2; > > f(..., > > - (e1 a e2) > > + e1 > > ,...); > > > > Signed-off-by: Elise Lennion > > --- > > drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c | 5 ++--- > > drivers/staging/lustre/lustre/llite/vvp_io.c | 3 ++- > > 2 files changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c b/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c > > index 12647af..ec7f2a8 100644 > > --- a/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c > > +++ b/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c > > @@ -764,9 +764,8 @@ static int ldlm_bl_thread_main(void *arg) > > > > if (!blwi) { > > atomic_dec(&blp->blp_busy_threads); > > - l_wait_event_exclusive(blp->blp_waitq, > > - (blwi = ldlm_bl_get_work(blp)), > > - &lwi); > > + blwi = ldlm_bl_get_work(blp); > > + l_wait_event_exclusive(blp->blp_waitq, blwi, &lwi); > > This first change is broken, since l_wait_event_exclusive() is actually a > macro that is waiting until ldlm_bl_get_work() returns a work item. Moving > the blwi assignment before the wait means that this will wait forever. > > This can be ignored for now, as there is a patch in the pipeline to clean > up this code (http://review.whamcloud.com/5843) that James should be > getting close to pushing, and it removes this inline assignment. > > > busy = atomic_inc_return(&blp->blp_busy_threads); > > } else { > > busy = atomic_read(&blp->blp_busy_threads); > > diff --git a/drivers/staging/lustre/lustre/llite/vvp_io.c b/drivers/staging/lustre/lustre/llite/vvp_io.c > > index 1a4b897..87fdab2 100644 > > --- a/drivers/staging/lustre/lustre/llite/vvp_io.c > > +++ b/drivers/staging/lustre/lustre/llite/vvp_io.c > > @@ -450,7 +450,8 @@ static void vvp_io_advance(const struct lu_env *env, > > struct vvp_io *vio = cl2vvp_io(env, ios); > > CLOBINVRNT(env, obj, vvp_object_invariant(obj)); > > > > - iov_iter_reexpand(vio->vui_iter, vio->vui_tot_count -= nob); > > + vio->vui_tot_count -= nob; > > + iov_iter_reexpand(vio->vui_iter, vio->vui_tot_count); > > This one is fine. Please resubmit the patch with just this change. You > can add "Reviewed-by: Andreas Dilger " for that > patch. > > Cheers, Andreas > > > } > > > > static void vvp_io_update_iov(const struct lu_env *env, > > -- > > 2.7.4 > > > Sorry for the confusion with the macro usage, I'll send a v2 without this undesired change. thank you all for the detailed answer, elise