From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH 1/2] proc: Generalize proc inode allocation Date: Fri, 17 Jun 2011 16:31:57 -0700 Message-ID: References: <20110521093936.GA3015@p183> <20110521223054.GA3198@p183> <20110523014303.GA2351982@jupiter.n2.diac24.net> <20110523014751.GB2351982@jupiter.n2.diac24.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20110523014751.GB2351982@jupiter.n2.diac24.net> (David Lamparter's message of "Mon, 23 May 2011 03:47:51 +0200") Sender: netdev-owner@vger.kernel.org To: Linux Containers Cc: Alexey Dobriyan , netdev@vger.kernel.org, David Lamparter , linux-kernel@vger.kernel.org, "Serge E. Hallyn" List-Id: containers.vger.kernel.org Generalize the proc inode allocation so that it can be used without having to having to create a proc_dir_entry. This will allow namespace file descriptors to remain light weight entitities but still have the same inode number when the backing namespace is the same. Signed-off-by: Eric W. Biederman --- Baring problems in review I plan to merge these patches via my linux-2.6-nsfd tree. fs/proc/generic.c | 26 +++++++++++++------------- include/linux/proc_fs.h | 10 ++++++++++ 2 files changed, 23 insertions(+), 13 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index f1637f1..65416a1 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -350,14 +350,14 @@ static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */ * Return an inode number between PROC_DYNAMIC_FIRST and * 0xffffffff, or zero on failure. */ -static unsigned int get_inode_number(void) +int proc_alloc_inum(unsigned int *inum) { unsigned int i; int error; retry: - if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0) - return 0; + if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL)) + return -ENOMEM; spin_lock(&proc_inum_lock); error = ida_get_new(&proc_inum_ida, &i); @@ -365,18 +365,19 @@ retry: if (error == -EAGAIN) goto retry; else if (error) - return 0; + return error; if (i > UINT_MAX - PROC_DYNAMIC_FIRST) { spin_lock(&proc_inum_lock); ida_remove(&proc_inum_ida, i); spin_unlock(&proc_inum_lock); - return 0; + return -ENOSPC; } - return PROC_DYNAMIC_FIRST + i; + *inum = PROC_DYNAMIC_FIRST + i; + return 0; } -static void release_inode_number(unsigned int inum) +void proc_free_inum(unsigned int inum) { spin_lock(&proc_inum_lock); ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST); @@ -554,13 +555,12 @@ static const struct inode_operations proc_dir_inode_operations = { static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp) { - unsigned int i; struct proc_dir_entry *tmp; + int ret; - i = get_inode_number(); - if (i == 0) - return -EAGAIN; - dp->low_ino = i; + ret = proc_alloc_inum(&dp->low_ino); + if (ret) + return ret; if (S_ISDIR(dp->mode)) { if (dp->proc_iops == NULL) { @@ -766,7 +766,7 @@ EXPORT_SYMBOL(proc_create_data); static void free_proc_entry(struct proc_dir_entry *de) { - release_inode_number(de->low_ino); + proc_free_inum(de->low_ino); if (S_ISLNK(de->mode)) kfree(de->data); diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index e7576cf..3067b44 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -175,6 +175,8 @@ extern struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name, extern struct file *proc_ns_fget(int fd); +extern int proc_alloc_inum(unsigned int *pino); +extern void proc_free_inum(unsigned int inum); #else #define proc_net_fops_create(net, name, mode, fops) ({ (void)(mode), NULL; }) @@ -229,6 +231,14 @@ static inline struct file *proc_ns_fget(int fd) return ERR_PTR(-EINVAL); } +static inline int proc_alloc_inum(unsigned int *inum) +{ + *inum = 1; + return 0; +} +static inline void proc_free_inum(unsigned int inum) +{ +} #endif /* CONFIG_PROC_FS */ #if !defined(CONFIG_PROC_KCORE) -- 1.7.5.1.217.g4e3aa