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SubjectRe: [PATCH 5/5] staging: lustre: osc_page.c: Use list_for_each_entry_safe

> 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.
>
> 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>

NAK!!!!!!

This change was reverted in commit

cd15dd6ef4ea11df87f717b8b1b83aaa738ec8af

Doing these while (list_empty(..)) to list_for_entry...
are not simple changes and have broken things in lustre
before. Unless you really understand the state machine of
the lustre code I don't recommend these kinds of change
for lustre.

> ---
> 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
>
>

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