From b4df2b92d8461444fac429c75ba6e125c63056bc Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Mon, 27 Oct 2008 22:48:36 +0300 Subject: [PATCH] proc: stop using BKL There are four BKL users in proc: de_put(), proc_lookup_de(), proc_readdir_de(), proc_root_readdir(), 1) de_put() ----------- de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL needed. BKL doesn't matter to possible refcount leak as well. 2) proc_lookup_de() ------------------- Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is potentially blocking, all callers of proc_lookup_de() eventually end up from ->lookup hooks which is protected by directory's ->i_mutex -- BKL doesn't protect anything. 3) proc_readdir_de() -------------------- "." and ".." part doesn't need BKL, walking PDE list is under proc_subdir_lock, calling filldir callback is potentially blocking because it writes to luserspace. All proc_readdir_de() callers eventually come from ->readdir hook which is under directory's ->i_mutex -- BKL doesn't protect anything. 4) proc_root_readdir_de() ------------------------- proc_root_readdir_de is ->readdir hook, see (3). Since readdir hooks doesn't use BKL anymore, switch to generic_file_llseek, since it also takes directory's i_mutex. Signed-off-by: Alexey Dobriyan --- fs/proc/generic.c | 8 ++------ fs/proc/inode.c | 3 --- fs/proc/proc_net.c | 2 +- fs/proc/root.c | 8 +------- 4 files changed, 4 insertions(+), 17 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 60a359b35582..db7fa5cab988 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -14,7 +14,6 @@ #include #include #include -#include #include #include #include @@ -379,7 +378,6 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir, struct inode *inode = NULL; int error = -ENOENT; - lock_kernel(); spin_lock(&proc_subdir_lock); for (de = de->subdir; de ; de = de->next) { if (de->namelen != dentry->d_name.len) @@ -397,7 +395,6 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir, } spin_unlock(&proc_subdir_lock); out_unlock: - unlock_kernel(); if (inode) { dentry->d_op = &proc_dentry_operations; @@ -432,8 +429,6 @@ int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent, struct inode *inode = filp->f_path.dentry->d_inode; int ret = 0; - lock_kernel(); - ino = inode->i_ino; i = filp->f_pos; switch (i) { @@ -487,7 +482,7 @@ int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent, spin_unlock(&proc_subdir_lock); } ret = 1; -out: unlock_kernel(); +out: return ret; } @@ -504,6 +499,7 @@ int proc_readdir(struct file *filp, void *dirent, filldir_t filldir) * the /proc directory. */ static const struct file_operations proc_dir_operations = { + .llseek = generic_file_llseek, .read = generic_read_dir, .readdir = proc_readdir, }; diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 2543fd00c658..3e76bb9b3ad6 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -35,16 +35,13 @@ struct proc_dir_entry *de_get(struct proc_dir_entry *de) */ void de_put(struct proc_dir_entry *de) { - lock_kernel(); if (!atomic_read(&de->count)) { printk("de_put: entry %s already free!\n", de->name); - unlock_kernel(); return; } if (atomic_dec_and_test(&de->count)) free_proc_entry(de); - unlock_kernel(); } /* diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index 7bc296f424ae..04d1270f1c38 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -18,7 +18,6 @@ #include #include #include -#include #include #include #include @@ -172,6 +171,7 @@ static int proc_tgid_net_readdir(struct file *filp, void *dirent, } const struct file_operations proc_net_operations = { + .llseek = generic_file_llseek, .read = generic_read_dir, .readdir = proc_tgid_net_readdir, }; diff --git a/fs/proc/root.c b/fs/proc/root.c index 7761602af9de..f6299a25594e 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include @@ -162,17 +161,12 @@ static int proc_root_readdir(struct file * filp, unsigned int nr = filp->f_pos; int ret; - lock_kernel(); - if (nr < FIRST_PROCESS_ENTRY) { int error = proc_readdir(filp, dirent, filldir); - if (error <= 0) { - unlock_kernel(); + if (error <= 0) return error; - } filp->f_pos = FIRST_PROCESS_ENTRY; } - unlock_kernel(); ret = proc_pid_readdir(filp, dirent, filldir); return ret; -- 2.39.5