UPSTREAM: fs: provide locked helper variant of close_fd_get_file()
[ Upstream commit 53dec2ea74f2ef360e8455439be96a780baa6097 ]
Assumes current->files->file_lock is already held on invocation. Helps
the caller check the file before removing the fd, if it needs to.
Change-Id: Idd87700a119403ce3867aa52294a14213b505faa
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d2136fc145
)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
parent
82c3becbef
commit
00af4b88ad
48
fs/file.c
48
fs/file.c
@ -22,6 +22,8 @@
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#include <linux/close_range.h>
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#include <linux/close_range.h>
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#include <net/sock.h>
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#include <net/sock.h>
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#include "internal.h"
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unsigned int sysctl_nr_open __read_mostly = 1024*1024;
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unsigned int sysctl_nr_open __read_mostly = 1024*1024;
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unsigned int sysctl_nr_open_min = BITS_PER_LONG;
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unsigned int sysctl_nr_open_min = BITS_PER_LONG;
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/* our min() is unusable in constant expressions ;-/ */
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/* our min() is unusable in constant expressions ;-/ */
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@ -779,6 +781,32 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
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return 0;
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return 0;
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}
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}
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/*
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* See close_fd_get_file() below, this variant assumes current->files->file_lock
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* is held.
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*/
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int __close_fd_get_file(unsigned int fd, struct file **res)
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{
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struct files_struct *files = current->files;
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struct file *file;
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struct fdtable *fdt;
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fdt = files_fdtable(files);
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if (fd >= fdt->max_fds)
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goto out_err;
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file = fdt->fd[fd];
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if (!file)
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goto out_err;
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rcu_assign_pointer(fdt->fd[fd], NULL);
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__put_unused_fd(files, fd);
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get_file(file);
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*res = file;
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return 0;
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out_err:
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*res = NULL;
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return -ENOENT;
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}
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/*
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/*
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* variant of close_fd that gets a ref on the file for later fput.
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* variant of close_fd that gets a ref on the file for later fput.
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* The caller must ensure that filp_close() called on the file, and then
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* The caller must ensure that filp_close() called on the file, and then
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@ -787,27 +815,13 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
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int close_fd_get_file(unsigned int fd, struct file **res)
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int close_fd_get_file(unsigned int fd, struct file **res)
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{
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{
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struct files_struct *files = current->files;
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struct files_struct *files = current->files;
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struct file *file;
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int ret;
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struct fdtable *fdt;
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spin_lock(&files->file_lock);
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spin_lock(&files->file_lock);
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fdt = files_fdtable(files);
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ret = __close_fd_get_file(fd, res);
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if (fd >= fdt->max_fds)
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goto out_unlock;
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file = fdt->fd[fd];
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if (!file)
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goto out_unlock;
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rcu_assign_pointer(fdt->fd[fd], NULL);
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__put_unused_fd(files, fd);
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spin_unlock(&files->file_lock);
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spin_unlock(&files->file_lock);
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get_file(file);
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*res = file;
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return 0;
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out_unlock:
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return ret;
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spin_unlock(&files->file_lock);
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*res = NULL;
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return -ENOENT;
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}
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}
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void do_close_on_exec(struct files_struct *files)
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void do_close_on_exec(struct files_struct *files)
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@ -134,6 +134,7 @@ extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
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const char *, const struct open_flags *);
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const char *, const struct open_flags *);
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extern struct open_how build_open_how(int flags, umode_t mode);
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extern struct open_how build_open_how(int flags, umode_t mode);
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extern int build_open_flags(const struct open_how *how, struct open_flags *op);
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extern int build_open_flags(const struct open_how *how, struct open_flags *op);
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extern int __close_fd_get_file(unsigned int fd, struct file **res);
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long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
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long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
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int chmod_common(const struct path *path, umode_t mode);
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int chmod_common(const struct path *path, umode_t mode);
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