On Thu, 2024-09-12 at 17:49 -0400, Benjamin Marzinski wrote:
> Add a new optional checker class function, libcheck_need_wait() and a
> new function to call it, checker_need_wait(). This can be used to see
> if
> a path_checker is currently running. This will be used to determine
> if
> there are pending checkers that need to be waited for.
>
> Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> ---
> libmultipath/checkers.c | 12 +++++++++++-
> libmultipath/checkers.h | 4 +++-
> libmultipath/checkers/directio.c | 10 ++++++++++
> libmultipath/checkers/tur.c | 10 ++++++++++
> 4 files changed, 34 insertions(+), 2 deletions(-)
>
> diff --git a/libmultipath/checkers.c b/libmultipath/checkers.c
> index f3e98352..e2eda58d 100644
> --- a/libmultipath/checkers.c
> +++ b/libmultipath/checkers.c
> @@ -27,6 +27,7 @@ struct checker_class {
> void (*reset)(void); /* to reset the global
> variables */
> void *(*thread)(void *); /* async thread entry
> point */
> int (*pending)(struct checker *); /* to recheck pending
> paths */
> + bool (*need_wait)(struct checker *); /* checker needs
> waiting for */
> const char **msgtable;
> short msgtable_size;
> };
> @@ -182,7 +183,8 @@ static struct checker_class
> *add_checker_class(const char *name)
> c->reset = (void (*)(void)) dlsym(c->handle,
> "libcheck_reset");
> c->thread = (void *(*)(void*)) dlsym(c->handle,
> "libcheck_thread");
> c->pending = (int (*)(struct checker *)) dlsym(c->handle,
> "libcheck_pending");
> - /* These 4 functions can be NULL. call dlerror() to clear
> out any
> + c->need_wait = (bool (*)(struct checker *)) dlsym(c->handle,
> "libcheck_need_wait");
> + /* These 5 functions can be NULL. call dlerror() to clear
> out any
> * error string */
> dlerror();
>
> @@ -313,6 +315,14 @@ int checker_get_state(struct checker *c)
> return c->path_state;
> }
>
> +bool checker_need_wait(struct checker *c)
> +{
> + if (!c || !c->cls || c->path_state != PATH_PENDING ||
> + !c->cls->need_wait)
> + return false;
> + return c->cls->need_wait(c);
> +}
> +
> void checker_check (struct checker * c, int path_state)
> {
> if (!c)
> diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
> index b2342a1b..da91f499 100644
> --- a/libmultipath/checkers.h
> +++ b/libmultipath/checkers.h
> @@ -2,6 +2,7 @@
> #define CHECKERS_H_INCLUDED
>
> #include <pthread.h>
> +#include <stdbool.h>
> #include "list.h"
> #include "defaults.h"
>
> @@ -171,6 +172,7 @@ struct checker_context {
> int start_checker_thread (pthread_t *thread, const pthread_attr_t
> *attr,
> struct checker_context *ctx);
> int checker_get_state(struct checker *c);
> +bool checker_need_wait(struct checker *c);
> void checker_check (struct checker *, int);
> int checker_is_sync(const struct checker *);
> const char *checker_name (const struct checker *);
> @@ -191,7 +193,7 @@ void *libcheck_thread(struct checker_context
> *ctx);
> void libcheck_reset(void);
> int libcheck_mp_init(struct checker *);
> int libcheck_pending(struct checker *c);
> -
> +bool libcheck_need_wait(struct checker *c);
>
> /*
> * msgid => message map.
> diff --git a/libmultipath/checkers/directio.c
> b/libmultipath/checkers/directio.c
> index 904e3071..4beed02e 100644
> --- a/libmultipath/checkers/directio.c
> +++ b/libmultipath/checkers/directio.c
> @@ -65,6 +65,7 @@ struct directio_context {
> struct aio_group *aio_grp;
> struct async_req *req;
> struct timespec endtime;
> + bool waited_for;
> };
>
> static struct aio_group *
> @@ -295,6 +296,7 @@ check_pending(struct directio_context *ct, struct
> timespec endtime)
> int r;
> struct timespec currtime, timeout;
>
> + ct->waited_for = true;
Not sure if it's important, but strictly speaking, we have only waited
for the checker if the endtime was in the future, which is often not
the case. Otherwise we'd just have polled.
Martin
> while(1) {
> get_monotonic_time(&currtime);
> timespecsub(&endtime, &currtime, &timeout);
> @@ -346,6 +348,7 @@ check_state(int fd, struct directio_context *ct,
> int sync, int timeout_secs)
> get_monotonic_time(&ct->endtime);
> ct->endtime.tv_nsec += 1000 * 1000;
> normalize_timespec(&ct->endtime);
> + ct->waited_for = false;
> }
> ct->running++;
> if (!sync)
> @@ -386,6 +389,13 @@ static void set_msgid(struct checker *c, int
> state)
> }
> }
>
> +bool libcheck_need_wait(struct checker *c)
> +{
> + struct directio_context *ct = (struct directio_context *)c-
> >context;
> + return (ct && ct->running && ct->req->state == PATH_PENDING
> &&
> + !ct->waited_for);
> +}
> +
> int libcheck_pending(struct checker *c)
> {
> int rc;
> diff --git a/libmultipath/checkers/tur.c
> b/libmultipath/checkers/tur.c
> index 81db565b..41d6b9c3 100644
> --- a/libmultipath/checkers/tur.c
> +++ b/libmultipath/checkers/tur.c
> @@ -59,6 +59,7 @@ struct tur_checker_context {
> struct checker_context ctx;
> unsigned int nr_timeouts;
> struct timespec endtime;
> + bool waited_for;
> };
>
> int libcheck_init (struct checker * c)
> @@ -351,9 +352,17 @@ int check_pending(struct checker *c)
> ct->thread = 0;
> }
>
> + ct->waited_for = true;
> return tur_status;
> }
>
> +bool libcheck_need_wait(struct checker *c)
> +{
> + struct tur_checker_context *ct = c->context;
> + return (ct && ct->thread && uatomic_read(&ct->running) != 0
> &&
> + !ct->waited_for);
> +}
> +
> int libcheck_pending(struct checker *c)
> {
> struct tur_checker_context *ct = c->context;
> @@ -463,6 +472,7 @@ int libcheck_check(struct checker * c)
> pthread_mutex_unlock(&ct->lock);
> ct->fd = c->fd;
> ct->timeout = c->timeout;
> + ct->waited_for = false;
> uatomic_add(&ct->holders, 1);
> uatomic_set(&ct->running, 1);
> tur_set_async_timeout(c);
