From 5cdf4d6c89bdb802be234f2fccc8157b7228b546 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Thu, 19 Sep 2019 13:36:38 +0100 Subject: [PATCH] server: Remove tricksy initialization of struct b_conn_handle. b_conn_handle fields exportsize and can_* have a special meaning when they are -1. It means that the value of the field has not been computed and cached yet. The struct was being initialized using memset (_, -1, _) which does indeed have the effect of setting all the fields to -1, although it's somewhat non-obvious to say the least. This commit replaces it with ordinary field initialization, also setting h->handle to NULL. By keeping the initialization function next to the struct definition, hopefully they will be updated in tandem in future. GCC 9.2.1 actually optimizes this back into the memset equivalent using inline AVX instructions, so good job there! Simple refactoring, should have no effect on how the code works. See commit d60d0f4248610fc1d116dc9f249526d20913c9a3. --- server/connections.c | 3 +-- server/internal.h | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/server/connections.c b/server/connections.c index 3c4296ea..eeda85d5 100644 --- a/server/connections.c +++ b/server/connections.c @@ -269,9 +269,8 @@ new_connection (int sockin, int sockout, int nworkers) goto error; } conn->nr_handles = backend->i + 1; - memset (conn->handles, -1, conn->nr_handles * sizeof *conn->handles); for_each_backend (b) - conn->handles[b->i].handle = NULL; + reset_b_conn_handle (&conn->handles[b->i]); conn->status = 1; conn->nworkers = nworkers; diff --git a/server/internal.h b/server/internal.h index da4fae19..a376d739 100644 --- a/server/internal.h +++ b/server/internal.h @@ -168,6 +168,23 @@ struct b_conn_handle { int can_cache; }; +static inline void +reset_b_conn_handle (struct b_conn_handle *h) +{ + h->handle = NULL; + h->exportsize = -1; + h->can_write = -1; + h->can_flush = -1; + h->is_rotational = -1; + h->can_trim = -1; + h->can_zero = -1; + h->can_fast_zero = -1; + h->can_fua = -1; + h->can_multi_conn = -1; + h->can_extents = -1; + h->can_cache = -1; +} + struct connection { pthread_mutex_t request_lock; pthread_mutex_t read_lock; -- 2.11.4.GIT