Author: melifaro Date: Mon Nov 30 21:59:52 2020 New Revision: 368199 URL: https://svnweb.freebsd.org/changeset/base/368199
Log: Move inner loop logic out of sysctl_sysctl_next_ls(). Refactor sysctl_sysctl_next_ls(): * Move huge inner loop out of sysctl_sysctl_next_ls() into a separate non-recursive function, returning the next step to be taken. * Update resulting node oid parts only on successful lookup * Make sysctl_sysctl_next_ls() return boolean success/failure instead of errno, slightly simplifying logic Reviewed by: freqlabs Differential Revision: https://reviews.freebsd.org/D27029 Modified: head/sys/kern/kern_sysctl.c Modified: head/sys/kern/kern_sysctl.c ============================================================================== --- head/sys/kern/kern_sysctl.c Mon Nov 30 21:42:55 2020 (r368198) +++ head/sys/kern/kern_sysctl.c Mon Nov 30 21:59:52 2020 (r368199) @@ -1100,109 +1100,148 @@ sysctl_sysctl_name(SYSCTL_HANDLER_ARGS) static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NAME, name, CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_name, ""); +enum sysctl_iter_action { + ITER_SIBLINGS, /* Not matched, continue iterating siblings */ + ITER_CHILDREN, /* Node has children we need to iterate over them */ + ITER_FOUND, /* Matching node was found */ +}; + /* - * Walk the sysctl subtree at lsp until we find the given name, - * and return the next name in order by oid_number. + * Tries to find the next node for @name and @namelen. + * + * Returns next action to take. */ -static int -sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen, - int *next, int *len, int level, bool honor_skip) +static enum sysctl_iter_action +sysctl_sysctl_next_node(struct sysctl_oid *oidp, int *name, unsigned int namelen, + bool honor_skip) { - struct sysctl_oid *oidp; - SYSCTL_ASSERT_LOCKED(); - *len = level; - SLIST_FOREACH(oidp, lsp, oid_link) { - *next = oidp->oid_number; + if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0) + return (ITER_SIBLINGS); - if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0) - continue; + if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0) + return (ITER_SIBLINGS); - if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0) - continue; + if (namelen == 0) { + /* + * We have reached a node with a full name match and are + * looking for the next oid in its children. + * + * For CTL_SYSCTL_NEXTNOSKIP we are done. + * + * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it + * has a handler) and move on to the children. + */ + if (!honor_skip) + return (ITER_FOUND); + if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) + return (ITER_FOUND); + /* If node does not have an iterator, treat it as leaf */ + if (oidp->oid_handler) + return (ITER_FOUND); - if (namelen == 0) { - /* - * We have reached a node with a full name match and are - * looking for the next oid in its children. - * - * For CTL_SYSCTL_NEXTNOSKIP we are done. - * - * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it - * has a handler) and move on to the children. - */ - if (!honor_skip) - return (0); - if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) - return (0); - if (oidp->oid_handler) - return (0); - lsp = SYSCTL_CHILDREN(oidp); - if (!sysctl_sysctl_next_ls(lsp, NULL, 0, next + 1, len, - level + 1, honor_skip)) - return (0); - /* - * There were no useable children in this node. - * Continue searching for the next oid at this level. - */ - goto emptynode; - } + /* Report oid as a node to iterate */ + return (ITER_CHILDREN); + } + /* + * No match yet. Continue seeking the given name. + * + * We are iterating in order by oid_number, so skip oids lower + * than the one we are looking for. + * + * When the current oid_number is higher than the one we seek, + * that means we have reached the next oid in the sequence and + * should return it. + * + * If the oid_number matches the name at this level then we + * have to find a node to continue searching at the next level. + */ + if (oidp->oid_number < *name) + return (ITER_SIBLINGS); + if (oidp->oid_number > *name) { /* - * No match yet. Continue seeking the given name. + * We have reached the next oid. * - * We are iterating in order by oid_number, so skip oids lower - * than the one we are looking for. + * For CTL_SYSCTL_NEXTNOSKIP we are done. * - * When the current oid_number is higher than the one we seek, - * that means we have reached the next oid in the sequence and - * should return it. - * - * If the oid_number matches the name at this level then we - * have to find a node to continue searching at the next level. + * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it + * has a handler) and move on to the children. */ - if (oidp->oid_number < *name) - continue; - if (oidp->oid_number > *name) { - /* - * We have reached the next oid. - * - * For CTL_SYSCTL_NEXTNOSKIP we are done. - * - * For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it - * has a handler) and move on to the children. - */ - if (!honor_skip) - return (0); - if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) - return (0); - if (oidp->oid_handler) - return (0); - lsp = SYSCTL_CHILDREN(oidp); - if (!sysctl_sysctl_next_ls(lsp, name + 1, namelen - 1, - next + 1, len, level + 1, honor_skip)) - return (0); - goto next; - } + if (!honor_skip) + return (ITER_FOUND); if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) - continue; + return (ITER_FOUND); + /* If node does not have an iterator, treat it as leaf */ if (oidp->oid_handler) + return (ITER_FOUND); + return (ITER_CHILDREN); + } + + /* match at a current level */ + if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) + return (ITER_SIBLINGS); + if (oidp->oid_handler) + return (ITER_SIBLINGS); + + return (ITER_CHILDREN); +} + +/* + * Recursively walk the sysctl subtree at lsp until we find the given name. + * Returns true and fills in next oid data in @next and @len if oid is found. + */ +static bool +sysctl_sysctl_next_action(struct sysctl_oid_list *lsp, int *name, u_int namelen, + int *next, int *len, int level, bool honor_skip) +{ + struct sysctl_oid *oidp; + bool success = false; + enum sysctl_iter_action action; + + SYSCTL_ASSERT_LOCKED(); + SLIST_FOREACH(oidp, lsp, oid_link) { + action = sysctl_sysctl_next_node(oidp, name, namelen, honor_skip); + if (action == ITER_SIBLINGS) continue; + if (action == ITER_FOUND) { + success = true; + break; + } + KASSERT((action== ITER_CHILDREN), ("ret(%d)!=ITER_CHILDREN", action)); + lsp = SYSCTL_CHILDREN(oidp); - if (!sysctl_sysctl_next_ls(lsp, name + 1, namelen - 1, - next + 1, len, level + 1, honor_skip)) - return (0); - next: - /* - * There were no useable children in this node. - * Continue searching for the next oid at the root level. - */ - namelen = 1; - emptynode: - /* Reset len in case a failed recursive call changed it. */ - *len = level; + if (namelen == 0) { + success = sysctl_sysctl_next_action(lsp, NULL, 0, + next + 1, len, level + 1, honor_skip); + } else { + success = sysctl_sysctl_next_action(lsp, name + 1, namelen - 1, + next + 1, len, level + 1, honor_skip); + if (!success) { + + /* + * We maintain the invariant that current node oid + * is >= the oid provided in @name. + * As there are no usable children at this node, + * current node oid is strictly > than the requested + * oid. + * Hence, reduce namelen to 0 to allow for picking first + * nodes/leafs in the next node in list. + */ + namelen = 0; + } + } + if (success) + break; } - return (ENOENT); + + if (success) { + *next = oidp->oid_number; + if (level > *len) + *len = level; + } + + return (success); } static int @@ -1211,16 +1250,18 @@ sysctl_sysctl_next(SYSCTL_HANDLER_ARGS) int *name = (int *) arg1; u_int namelen = arg2; int len, error; + bool success; struct sysctl_oid_list *lsp = &sysctl__children; struct rm_priotracker tracker; int next[CTL_MAXNAME]; + len = 0; SYSCTL_RLOCK(&tracker); - error = sysctl_sysctl_next_ls(lsp, name, namelen, next, &len, 1, + success = sysctl_sysctl_next_action(lsp, name, namelen, next, &len, 1, oidp->oid_number == CTL_SYSCTL_NEXT); SYSCTL_RUNLOCK(&tracker); - if (error) - return (error); + if (!success) + return (ENOENT); error = SYSCTL_OUT(req, next, len * sizeof (int)); return (error); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
