From a16bbc3430ed94b543222f4c8ef68025f8493e93 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 20 Nov 2009 16:08:55 -0800 Subject: sysfs: Gut sysfs_addrm_start and sysfs_addrm_finish With lazy inode updates and dentry operations bringing everything into sync on demand there is no longer any need to immediately update the vfs or grab i_mutex to protect those updates as we make changes to sysfs. Acked-by: Serge Hallyn Acked-by: Tejun Heo Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 91 +++----------------------------------------------------- fs/sysfs/sysfs.h | 2 -- 2 files changed, 4 insertions(+), 89 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index e319379d36db..f3af45e47eaa 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -386,12 +386,6 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) return NULL; } -static int sysfs_ilookup_test(struct inode *inode, void *arg) -{ - struct sysfs_dirent *sd = arg; - return inode->i_ino == sd->s_ino; -} - /** * sysfs_addrm_start - prepare for sysfs_dirent add/remove * @acxt: pointer to sysfs_addrm_cxt to be used @@ -399,47 +393,20 @@ static int sysfs_ilookup_test(struct inode *inode, void *arg) * * This function is called when the caller is about to add or * remove sysfs_dirent under @parent_sd. This function acquires - * sysfs_mutex, grabs inode for @parent_sd if available and lock - * i_mutex of it. @acxt is used to keep and pass context to + * sysfs_mutex. @acxt is used to keep and pass context to * other addrm functions. * * LOCKING: * Kernel thread context (may sleep). sysfs_mutex is locked on - * return. i_mutex of parent inode is locked on return if - * available. + * return. */ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *parent_sd) { - struct inode *inode; - memset(acxt, 0, sizeof(*acxt)); acxt->parent_sd = parent_sd; - /* Lookup parent inode. inode initialization is protected by - * sysfs_mutex, so inode existence can be determined by - * looking up inode while holding sysfs_mutex. - */ mutex_lock(&sysfs_mutex); - - inode = ilookup5(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, - parent_sd); - if (inode) { - WARN_ON(inode->i_state & I_NEW); - - /* parent inode available */ - acxt->parent_inode = inode; - - /* sysfs_mutex is below i_mutex in lock hierarchy. - * First, trylock i_mutex. If fails, unlock - * sysfs_mutex and lock them in order. - */ - if (!mutex_trylock(&inode->i_mutex)) { - mutex_unlock(&sysfs_mutex); - mutex_lock(&inode->i_mutex); - mutex_lock(&sysfs_mutex); - } - } } /** @@ -471,11 +438,6 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) sd->s_parent = sysfs_get(acxt->parent_sd); - if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) - inc_nlink(acxt->parent_inode); - - acxt->cnt++; - sysfs_link_sibling(sd); /* Update timestamps on the parent */ @@ -579,40 +541,6 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) sd->s_flags |= SYSFS_FLAG_REMOVED; sd->s_sibling = acxt->removed; acxt->removed = sd; - - if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) - drop_nlink(acxt->parent_inode); - - acxt->cnt++; -} - -/** - * sysfs_dec_nlink - Decrement link count for the specified sysfs_dirent - * @sd: target sysfs_dirent - * - * Decrement nlink for @sd. @sd must have been unlinked from its - * parent on entry to this function such that it can't be looked - * up anymore. - */ -static void sysfs_dec_nlink(struct sysfs_dirent *sd) -{ - struct inode *inode; - - inode = ilookup(sysfs_sb, sd->s_ino); - if (!inode) - return; - - /* adjust nlink and update timestamp */ - mutex_lock(&inode->i_mutex); - - inode->i_ctime = CURRENT_TIME; - drop_nlink(inode); - if (sysfs_type(sd) == SYSFS_DIR) - drop_nlink(inode); - - mutex_unlock(&inode->i_mutex); - - iput(inode); } /** @@ -621,25 +549,15 @@ static void sysfs_dec_nlink(struct sysfs_dirent *sd) * * Finish up sysfs_dirent add/remove. Resources acquired by * sysfs_addrm_start() are released and removed sysfs_dirents are - * cleaned up. Timestamps on the parent inode are updated. + * cleaned up. * * LOCKING: - * All mutexes acquired by sysfs_addrm_start() are released. + * sysfs_mutex is released. */ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) { /* release resources acquired by sysfs_addrm_start() */ mutex_unlock(&sysfs_mutex); - if (acxt->parent_inode) { - struct inode *inode = acxt->parent_inode; - - /* if added/removed, update timestamps on the parent */ - if (acxt->cnt) - inode->i_ctime = inode->i_mtime = CURRENT_TIME; - - mutex_unlock(&inode->i_mutex); - iput(inode); - } /* kill removed sysfs_dirents */ while (acxt->removed) { @@ -648,7 +566,6 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) acxt->removed = sd->s_sibling; sd->s_sibling = NULL; - sysfs_dec_nlink(sd); sysfs_deactivate(sd); unmap_bin_file(sd); sysfs_put(sd); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 12ccc07459d8..90b35012abb2 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -89,9 +89,7 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd) */ struct sysfs_addrm_cxt { struct sysfs_dirent *parent_sd; - struct inode *parent_inode; struct sysfs_dirent *removed; - int cnt; }; /* -- cgit v1.2.3-59-g8ed1b