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Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c30
1 files changed, 24 insertions, 6 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 72a1acd03675..988f6bbfc4bd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3870,12 +3870,12 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx)
if (!dir_emit_dots(file, ctx))
return 0;
- /* f_version caches the tgid value that the last readdir call couldn't
- * return. lseek aka telldir automagically resets f_version to 0.
+ /* We cache the tgid value that the last readdir call couldn't
+ * return and lseek resets it to 0.
*/
ns = proc_pid_ns(inode->i_sb);
- tid = (int)file->f_version;
- file->f_version = 0;
+ tid = (int)(intptr_t)file->private_data;
+ file->private_data = NULL;
for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
task;
task = next_tid(task), ctx->pos++) {
@@ -3890,7 +3890,7 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx)
proc_task_instantiate, task, NULL)) {
/* returning this tgid failed, save it as the first
* pid for the next readir call */
- file->f_version = (u64)tid;
+ file->private_data = (void *)(intptr_t)tid;
put_task_struct(task);
break;
}
@@ -3915,6 +3915,24 @@ static int proc_task_getattr(struct mnt_idmap *idmap,
return 0;
}
+/*
+ * proc_task_readdir() set @file->private_data to a positive integer
+ * value, so casting that to u64 is safe. generic_llseek_cookie() will
+ * set @cookie to 0, so casting to an int is safe. The WARN_ON_ONCE() is
+ * here to catch any unexpected change in behavior either in
+ * proc_task_readdir() or generic_llseek_cookie().
+ */
+static loff_t proc_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+ u64 cookie = (u64)(intptr_t)file->private_data;
+ loff_t off;
+
+ off = generic_llseek_cookie(file, offset, whence, &cookie);
+ WARN_ON_ONCE(cookie > INT_MAX);
+ file->private_data = (void *)(intptr_t)cookie; /* serialized by f_pos_lock */
+ return off;
+}
+
static const struct inode_operations proc_task_inode_operations = {
.lookup = proc_task_lookup,
.getattr = proc_task_getattr,
@@ -3925,7 +3943,7 @@ static const struct inode_operations proc_task_inode_operations = {
static const struct file_operations proc_task_operations = {
.read = generic_read_dir,
.iterate_shared = proc_task_readdir,
- .llseek = generic_file_llseek,
+ .llseek = proc_dir_llseek,
};
void __init set_proc_pid_nlink(void)