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author | Al Viro <viro@zeniv.linux.org.uk> | 2013-04-03 19:07:30 -0400 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-04-09 15:16:51 -0400 |
commit | 866ad9a747bbf5461739fcae6d0a41c8971bbe1d (patch) | |
tree | 6a94d3434bbb9034f9aeed68a59e799abf7f8ff2 /fs/proc/generic.c | |
parent | ad147d011f4e9d4e4309f7974fd19c7f875ccb14 (diff) | |
download | linux-866ad9a747bbf5461739fcae6d0a41c8971bbe1d.tar.gz linux-866ad9a747bbf5461739fcae6d0a41c8971bbe1d.tar.bz2 linux-866ad9a747bbf5461739fcae6d0a41c8971bbe1d.zip |
procfs: preparations for remove_proc_entry() race fixes
* leave ->proc_fops alone; make ->pde_users negative instead
* trim pde_opener
* move relevant code in fs/proc/inode.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/proc/generic.c')
-rw-r--r-- | fs/proc/generic.c | 83 |
1 files changed, 3 insertions, 80 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c index a6a1cb5d589d..bec58323629c 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -39,7 +39,7 @@ static int proc_match(unsigned int len, const char *name, struct proc_dir_entry /* buffer size is one page but our output routines use some slack for overruns */ #define PROC_BLOCK_SIZE (PAGE_SIZE - 1024) -static ssize_t +ssize_t __proc_file_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { @@ -171,48 +171,6 @@ __proc_file_read(struct file *file, char __user *buf, size_t nbytes, return retval; } -static ssize_t -proc_file_read(struct file *file, char __user *buf, size_t nbytes, - loff_t *ppos) -{ - struct proc_dir_entry *pde = PDE(file_inode(file)); - ssize_t rv = -EIO; - - spin_lock(&pde->pde_unload_lock); - if (!pde->proc_fops) { - spin_unlock(&pde->pde_unload_lock); - return rv; - } - pde->pde_users++; - spin_unlock(&pde->pde_unload_lock); - - rv = __proc_file_read(file, buf, nbytes, ppos); - - pde_users_dec(pde); - return rv; -} - -static loff_t -proc_file_lseek(struct file *file, loff_t offset, int orig) -{ - loff_t retval = -EINVAL; - switch (orig) { - case 1: - offset += file->f_pos; - /* fallthrough */ - case 0: - if (offset < 0 || offset > MAX_NON_LFS) - break; - file->f_pos = retval = offset; - } - return retval; -} - -static const struct file_operations proc_file_operations = { - .llseek = proc_file_lseek, - .read = proc_file_read, -}; - static int proc_notify_change(struct dentry *dentry, struct iattr *iattr) { struct inode *inode = dentry->d_inode; @@ -722,41 +680,6 @@ void pde_put(struct proc_dir_entry *pde) free_proc_entry(pde); } -static void entry_rundown(struct proc_dir_entry *de) -{ - spin_lock(&de->pde_unload_lock); - /* - * Stop accepting new callers into module. If you're - * dynamically allocating ->proc_fops, save a pointer somewhere. - */ - de->proc_fops = NULL; - /* Wait until all existing callers into module are done. */ - if (de->pde_users > 0) { - DECLARE_COMPLETION_ONSTACK(c); - - if (!de->pde_unload_completion) - de->pde_unload_completion = &c; - - spin_unlock(&de->pde_unload_lock); - - wait_for_completion(de->pde_unload_completion); - - spin_lock(&de->pde_unload_lock); - } - - while (!list_empty(&de->pde_openers)) { - struct pde_opener *pdeo; - - pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh); - list_del(&pdeo->lh); - spin_unlock(&de->pde_unload_lock); - pdeo->release(pdeo->inode, pdeo->file); - kfree(pdeo); - spin_lock(&de->pde_unload_lock); - } - spin_unlock(&de->pde_unload_lock); -} - /* * Remove a /proc entry and free it if it's not currently in use. */ @@ -788,7 +711,7 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) return; } - entry_rundown(de); + proc_entry_rundown(de); if (S_ISDIR(de->mode)) parent->nlink--; @@ -837,7 +760,7 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) } spin_unlock(&proc_subdir_lock); - entry_rundown(de); + proc_entry_rundown(de); next = de->parent; if (S_ISDIR(de->mode)) next->nlink--; |