From owner-freebsd-hackers@FreeBSD.ORG Tue Nov 4 09:52:05 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E658D2E8 for ; Tue, 4 Nov 2014 09:52:04 +0000 (UTC) Received: from ustc.edu.cn (email6.ustc.edu.cn [IPv6:2001:da8:d800::8]) by mx1.freebsd.org (Postfix) with ESMTP id 104F5258 for ; Tue, 4 Nov 2014 09:52:03 +0000 (UTC) Received: from freebsd.my.domain (unknown [58.211.218.74]) by newmailweb.ustc.edu.cn (Coremail) with SMTP id LkAmygAXiT23oVhUx5XNAA--.19170S2; Tue, 04 Nov 2014 17:51:55 +0800 (CST) From: Tiwei Bie To: mjguzik@gmail.com Subject: [PATCH] Finish the task 'Embedd group table into struct ucred' Date: Tue, 4 Nov 2014 17:51:26 +0800 Message-Id: <1415094686-39302-1-git-send-email-btw@mail.ustc.edu.cn> X-Mailer: git-send-email 2.1.2 X-CM-TRANSID: LkAmygAXiT23oVhUx5XNAA--.19170S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Cr4xCr1DWrW8JFW3Kr4xXrb_yoW8tw4Dpa 9Yyw15KF47J34DGr97t3yqvr4Iyw1ruFyDG3yrZr1aqryftF15AF15ZFWYkryYgF1rGr43 tF1fAw18Ar93A3JanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkIb7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwV C2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Cr0_Gr 1UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCY02Avz4vE14v_GFWl42xK 82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGw C20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1Y6r17MIIYrxkI7VAKI48J MIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMI IF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvE x4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsGvfC2KfnxnUUI43ZEXa7IU5g4S3UUUUU== X-CM-SenderInfo: xewzqzxdloh3xvwfhvlgxou0/1tbiAQURAVQhl8y9PQABs7 Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Nov 2014 09:52:05 -0000 Hi, Mateusz! I have finished the task: Embedd group table into struct ucred [1]. This is an explanation of my patch: In crextend(), when n <= XU_NGROUPS, I did such updates directly: cr->cr_groups = cr->cr_smallgroups; cr->cr_agroups = XU_NGROUPS; Because there is a check in the front of this function: if (n <= cr->cr_agroups) return; So when n <= XU_NGROUPS, cr->cr_groups would never point to the memory allocated by malloc(), and it won't need to be freed. Following is my patch: diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c index 9b2bcd8..76d2cfc 100644 --- a/sys/kern/kern_prot.c +++ b/sys/kern/kern_prot.c @@ -1864,7 +1864,8 @@ crfree(struct ucred *cr) #ifdef MAC mac_cred_destroy(cr); #endif - free(cr->cr_groups, M_CRED); + if (cr->cr_groups != cr->cr_smallgroups) + free(cr->cr_groups, M_CRED); free(cr, M_CRED); } } @@ -1976,6 +1977,12 @@ crextend(struct ucred *cr, int n) if (n <= cr->cr_agroups) return; + if (n <= XU_NGROUPS) { + cr->cr_groups = cr->cr_smallgroups; + cr->cr_agroups = XU_NGROUPS; + return; + } + /* * We extend by 2 each time since we're using a power of two * allocator until we need enough groups to fill a page. @@ -1997,7 +2004,7 @@ crextend(struct ucred *cr, int n) cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t)); /* Free the old array. */ - if (cr->cr_groups) + if (cr->cr_groups && cr->cr_groups != cr->cr_smallgroups) free(cr->cr_groups, M_CRED); cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO); diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h index 81e4520..a6531c4 100644 --- a/sys/sys/ucred.h +++ b/sys/sys/ucred.h @@ -37,6 +37,8 @@ struct loginclass; +#define XU_NGROUPS 16 + /* * Credentials. * @@ -64,13 +66,12 @@ struct ucred { struct auditinfo_addr cr_audit; /* Audit properties. */ gid_t *cr_groups; /* groups */ int cr_agroups; /* Available groups */ + gid_t cr_smallgroups[XU_NGROUPS]; /* storage for small groups */ }; #define NOCRED ((struct ucred *)0) /* no credential available */ #define FSCRED ((struct ucred *)-1) /* filesystem credential */ #endif /* _KERNEL || _WANT_UCRED */ -#define XU_NGROUPS 16 - /* * Flags for cr_flags. */ -- 2.1.0 [1] https://wiki.freebsd.org/JuniorJobs#Embedd_group_table_into_struct_ucred Tiwei Bie