Messages in this thread Patch in this message | | | Date | Fri, 24 Oct 2008 15:46:06 +0400 | From | Alexey Dobriyan <> | Subject | [PATCH] proc: stop using BKL |
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[added to proc.git]
commit e137447fbf30784a86b79707ef0d76de8c6bcf8d Author: Alexey Dobriyan <adobriyan@gmail.com> Date: Fri Oct 24 15:30:36 2008 +0400
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). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 60a359b..988a807 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -14,7 +14,6 @@ #include <linux/stat.h> #include <linux/module.h> #include <linux/mount.h> -#include <linux/smp_lock.h> #include <linux/init.h> #include <linux/idr.h> #include <linux/namei.h> @@ -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; } diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 2543fd0..3e76bb9 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 7bc296f..a7bd61e 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -18,7 +18,6 @@ #include <linux/sched.h> #include <linux/module.h> #include <linux/bitops.h> -#include <linux/smp_lock.h> #include <linux/mount.h> #include <linux/nsproxy.h> #include <net/net_namespace.h> diff --git a/fs/proc/root.c b/fs/proc/root.c index 7761602..f6299a2 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -16,7 +16,6 @@ #include <linux/sched.h> #include <linux/module.h> #include <linux/bitops.h> -#include <linux/smp_lock.h> #include <linux/mount.h> #include <linux/pid_namespace.h> @@ -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;
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