From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: [PATCH 1/3] plist: add plist_last Date: Mon, 28 Jun 2010 12:41:25 -0500 Message-ID: <1277746885.10879.197.camel@mulgrave.site> References: <1277746434.10879.191.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1277746434.10879.191.camel@mulgrave.site> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Linux PM Cc: Daniel Walker , Thomas Gleixner , markgross@thegnar.org List-Id: linux-pm@vger.kernel.org plist is currently used by the scheduler, which only needs to know the highest item in the list. This adds plist_last which allows you to find the lowest. This is necessary for using plists to implement a fast search of dynamic ranges in pm_qos which can have both highest and lowest criteria. Signed-off-by: James Bottomley --- include/linux/plist.h | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/include/linux/plist.h b/include/linux/plist.h index 6898985..7254eda 100644 --- a/include/linux/plist.h +++ b/include/linux/plist.h @@ -260,6 +260,23 @@ static inline int plist_node_empty(const struct plist_node *node) #endif /** + * plist_last_entry - get the struct for the last entry + * @head: the &struct plist_head pointer + * @type: the type of the struct this is embedded in + * @member: the name of the list_struct within the struct + */ +#ifdef CONFIG_DEBUG_PI_LIST +# define plist_last_entry(head, type, member) \ +({ \ + WARN_ON(plist_head_empty(head)); \ + container_of(plist_last(head), type, member); \ +}) +#else +# define plist_last_entry(head, type, member) \ + container_of(plist_last(head), type, member) +#endif + +/** * plist_first - return the first node (and thus, highest priority) * @head: the &struct plist_head pointer * @@ -271,4 +288,16 @@ static inline struct plist_node *plist_first(const struct plist_head *head) struct plist_node, plist.node_list); } +/** + * plist_last - return the last node (and thus, lowest priority) + * @head: the &struct plist_head pointer + * + * Assumes the plist is _not_ empty. + */ +static inline struct plist_node *plist_last(const struct plist_head *head) +{ + return list_entry(head->node_list.prev, + struct plist_node, plist.node_list); +} + #endif -- 1.6.4.2