lkml.org 
[lkml]   [2017]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Outreachy kernel] [PATCH 5/5] staging: lustre: osc_page.c: Use list_for_each_entry_safe


On Sun, 5 Mar 2017, Julia Lawall wrote:

>
>
> On Sun, 5 Mar 2017, simran singhal wrote:
>
> > Doubly linked lists which are iterated using list_empty
> > and list_entry macros have been replaced with list_for_each_entry_safe
> > macro.
> > This makes the iteration simpler and more readable.
> >
> > This patch replaces the while loop containing list_empty and list_entry
> > with list_for_each_entry_safe.
>
> list_for_each_entry_safe is only needed when the current element is
> removed from the list within the loop body. If that is not the case, you
> can just use list_for_each_entry.

Sorry, my comment was likely completely off the mark here. I was thinking
that the original code was using list_for_each. With the while
(!list_empty pattern, the safe version is definitely needed.

julia

>
> julia
>
>
> >
> > This was done with Coccinelle.
> >
> > @@
> > expression E1;
> > identifier I1, I2;
> > type T;
> > iterator name list_for_each_entry_safe;
> > @@
> >
> > T *I1;
> > + T *tmp;
> > ...
> > - while (list_empty(&E1) == 0)
> > + list_for_each_entry_safe (I1, tmp, &E1, I2)
> > {
> > ...when != T *I1;
> > - I1 = list_entry(E1.next, T, I2);
> > ...
> > }
> >
> > Signed-off-by: simran singhal <singhalsimran0@gmail.com>
> > ---
> > drivers/staging/lustre/lustre/osc/osc_page.c | 11 ++++-------
> > 1 file changed, 4 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/staging/lustre/lustre/osc/osc_page.c b/drivers/staging/lustre/lustre/osc/osc_page.c
> > index ed8a0dc..e8b974f 100644
> > --- a/drivers/staging/lustre/lustre/osc/osc_page.c
> > +++ b/drivers/staging/lustre/lustre/osc/osc_page.c
> > @@ -542,6 +542,7 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
> > struct cl_object *clobj = NULL;
> > struct cl_page **pvec;
> > struct osc_page *opg;
> > + struct osc_page *tmp;
> > int maxscan = 0;
> > long count = 0;
> > int index = 0;
> > @@ -572,7 +573,7 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
> > if (force)
> > cli->cl_lru_reclaim++;
> > maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
> > - while (!list_empty(&cli->cl_lru_list)) {
> > + list_for_each_entry_safe(opg, tmp, &cli->cl_lru_list, ops_lru) {
> > struct cl_page *page;
> > bool will_free = false;
> >
> > @@ -582,8 +583,6 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
> > if (--maxscan < 0)
> > break;
> >
> > - opg = list_entry(cli->cl_lru_list.next, struct osc_page,
> > - ops_lru);
> > page = opg->ops_cl.cpl_page;
> > if (lru_page_busy(cli, page)) {
> > list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
> > @@ -1043,6 +1042,7 @@ unsigned long osc_cache_shrink_scan(struct shrinker *sk,
> > {
> > struct client_obd *stop_anchor = NULL;
> > struct client_obd *cli;
> > + struct client_obd *tmp;
> > struct lu_env *env;
> > long shrank = 0;
> > u16 refcheck;
> > @@ -1059,10 +1059,7 @@ unsigned long osc_cache_shrink_scan(struct shrinker *sk,
> > return SHRINK_STOP;
> >
> > spin_lock(&osc_shrink_lock);
> > - while (!list_empty(&osc_shrink_list)) {
> > - cli = list_entry(osc_shrink_list.next, struct client_obd,
> > - cl_shrink_list);
> > -
> > + list_for_each_entry_safe(cli, tmp, &osc_shrink_list, cl_shrink_list) {
> > if (!stop_anchor)
> > stop_anchor = cli;
> > else if (cli == stop_anchor)
> > --
> > 2.7.4
> >
> > --
> > You received this message because you are subscribed to the Google Groups "outreachy-kernel" group.
> > To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com.
> > To post to this group, send email to outreachy-kernel@googlegroups.com.
> > To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/1488733610-22289-6-git-send-email-singhalsimran0%40gmail.com.
> > For more options, visit https://groups.google.com/d/optout.
> >
>

\
 
 \ /
  Last update: 2017-03-05 18:27    [W:0.096 / U:2.432 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site