[lustre-devel] [PATCH 04/21] lustre: use list*entry macros in place of container_of()
NeilBrown
neilb at suse.com
Sun Feb 10 19:14:15 PST 2019
On Mon, Feb 11 2019, James Simmons wrote:
>> There are a number of places that use container_of() but where
>> list_first_entry(), or list_last_entry() make the meaning more clear.
>> So change them over.
>
> I have to say normally the patches you see genernally use the basic
> functionality of the linux list implementation. I wonder if a deep
> dive on LUG's developers day would be a good idea.
It is possible to take the "new macro for subtly different case"
exercise too far, though in this particular case, I think using
replacing container_of with list_entry is a clear win.
Maybe a broader discussion would help
>
> Reviewed-by: James Simmons <jsimmons at infradead.org>
Thanks,
NeilBrown
>
>> Signed-off-by: NeilBrown <neilb at suse.com>
>> ---
>> drivers/staging/lustre/lustre/ldlm/ldlm_resource.c | 4 ++--
>> drivers/staging/lustre/lustre/obdclass/cl_io.c | 4 ++--
>> drivers/staging/lustre/lustre/obdclass/cl_object.c | 13 ++++++++-----
>> drivers/staging/lustre/lustre/obdclass/cl_page.c | 4 ++--
>> drivers/staging/lustre/lustre/obdclass/lu_object.c | 7 +++----
>> 5 files changed, 17 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
>> index 85c5047f4ba2..74c7644d6ef8 100644
>> --- a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
>> +++ b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
>> @@ -987,8 +987,8 @@ struct ldlm_namespace *ldlm_namespace_first_locked(enum ldlm_side client)
>> {
>> LASSERT(mutex_is_locked(ldlm_namespace_lock(client)));
>> LASSERT(!list_empty(ldlm_namespace_list(client)));
>> - return container_of(ldlm_namespace_list(client)->next,
>> - struct ldlm_namespace, ns_list_chain);
>> + return list_first_entry(ldlm_namespace_list(client),
>> + struct ldlm_namespace, ns_list_chain);
>> }
>>
>> /** Create and initialize new resource. */
>> diff --git a/drivers/staging/lustre/lustre/obdclass/cl_io.c b/drivers/staging/lustre/lustre/obdclass/cl_io.c
>> index 7bf02350f19d..34b4e63e7d1a 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/cl_io.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/cl_io.c
>> @@ -93,8 +93,8 @@ void cl_io_fini(const struct lu_env *env, struct cl_io *io)
>> LINVRNT(cl_io_invariant(io));
>>
>> while (!list_empty(&io->ci_layers)) {
>> - slice = container_of(io->ci_layers.prev, struct cl_io_slice,
>> - cis_linkage);
>> + slice = list_last_entry(&io->ci_layers, struct cl_io_slice,
>> + cis_linkage);
>> list_del_init(&slice->cis_linkage);
>> if (slice->cis_iop->op[io->ci_type].cio_fini)
>> slice->cis_iop->op[io->ci_type].cio_fini(env, slice);
>> diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> index 05d784ae7a6c..f724b2d62df1 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> @@ -649,8 +649,8 @@ static struct lu_env *cl_env_obtain(void *debug)
>> if (cl_envs[cpu].cec_count > 0) {
>> int rc;
>>
>> - cle = container_of(cl_envs[cpu].cec_envs.next, struct cl_env,
>> - ce_linkage);
>> + cle = list_first_entry(&cl_envs[cpu].cec_envs, struct cl_env,
>> + ce_linkage);
>> list_del_init(&cle->ce_linkage);
>> cl_envs[cpu].cec_count--;
>> read_unlock(&cl_envs[cpu].cec_guard);
>> @@ -748,9 +748,12 @@ unsigned int cl_env_cache_purge(unsigned int nr)
>>
>> for_each_possible_cpu(i) {
>> write_lock(&cl_envs[i].cec_guard);
>> - for (; !list_empty(&cl_envs[i].cec_envs) && nr > 0; --nr) {
>> - cle = container_of(cl_envs[i].cec_envs.next,
>> - struct cl_env, ce_linkage);
>> + for (; nr >0 &&
>> + (cle = list_first_entry_or_null(
>> + &cl_envs[i].cec_envs,
>> + struct cl_env,
>> + ce_linkage)) != NULL;
>> + --nr) {
>> list_del_init(&cle->ce_linkage);
>> LASSERT(cl_envs[i].cec_count > 0);
>> cl_envs[i].cec_count--;
>> diff --git a/drivers/staging/lustre/lustre/obdclass/cl_page.c b/drivers/staging/lustre/lustre/obdclass/cl_page.c
>> index b1b4dc7ea22f..d025ea55818f 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/cl_page.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/cl_page.c
>> @@ -690,8 +690,8 @@ int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg)
>> const struct cl_page_slice *slice;
>> int result;
>>
>> - slice = container_of(pg->cp_layers.next,
>> - const struct cl_page_slice, cpl_linkage);
>> + slice = list_first_entry(&pg->cp_layers,
>> + const struct cl_page_slice, cpl_linkage);
>> PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked);
>> /*
>> * Call ->cpo_is_vmlocked() directly instead of going through
>> diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
>> index 3bd48748f46c..639c298b6a90 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
>> @@ -349,7 +349,7 @@ static void lu_object_free(const struct lu_env *env, struct lu_object *o)
>> * lives as long as possible and ->loo_object_free() methods
>> * can look at its contents.
>> */
>> - o = container_of(splice.prev, struct lu_object, lo_linkage);
>> + o = list_last_entry(&splice, struct lu_object, lo_linkage);
>> list_del_init(&o->lo_linkage);
>> o->lo_ops->loo_object_free(env, o);
>> }
>> @@ -432,9 +432,8 @@ int lu_site_purge_objects(const struct lu_env *env, struct lu_site *s,
>> * Free everything on the dispose list. This is safe against
>> * races due to the reasons described in lu_object_put().
>> */
>> - while (!list_empty(&dispose)) {
>> - h = container_of(dispose.next,
>> - struct lu_object_header, loh_lru);
>> + while ((h = list_first_entry_or_null(
>> + &dispose, struct lu_object_header, loh_lru)) != NULL) {
>> list_del_init(&h->loh_lru);
>> lu_object_free(env, lu_object_top(h));
>> lprocfs_counter_incr(s->ls_stats, LU_SS_LRU_PURGED);
>>
>>
>>
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