From 0f0a0e54a2a15174535349db3a22355a6b1cf5fa Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 11 Jun 2018 15:17:58 -0400 Subject: [PATCH] devpts: Convert to new IDA API ida_alloc_max() matches what this driver wants to do. Also removes a call to ida_pre_get(). We no longer need the protection of the mutex, so convert pty_count to an atomic_t and remove the mutex entirely. Signed-off-by: Matthew Wilcox --- fs/devpts/inode.c | 45 ++++++++++++--------------------------------- 1 file changed, 12 insertions(+), 33 deletions(-) diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index e072e955ce33..c53814539070 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -46,7 +46,7 @@ static int pty_limit = NR_UNIX98_PTY_DEFAULT; static int pty_reserve = NR_UNIX98_PTY_RESERVE; static int pty_limit_min; static int pty_limit_max = INT_MAX; -static int pty_count; +static atomic_t pty_count = ATOMIC_INIT(0); static struct ctl_table pty_table[] = { { @@ -93,8 +93,6 @@ static struct ctl_table pty_root_table[] = { {} }; -static DEFINE_MUTEX(allocated_ptys_lock); - struct pts_mount_opts { int setuid; int setgid; @@ -533,44 +531,25 @@ static struct file_system_type devpts_fs_type = { int devpts_new_index(struct pts_fs_info *fsi) { - int index; - int ida_ret; + int index = -ENOSPC; -retry: - if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) - return -ENOMEM; + if (atomic_inc_return(&pty_count) >= (pty_limit - + (fsi->mount_opts.reserve ? 0 : pty_reserve))) + goto out; - mutex_lock(&allocated_ptys_lock); - if (pty_count >= (pty_limit - - (fsi->mount_opts.reserve ? 0 : pty_reserve))) { - mutex_unlock(&allocated_ptys_lock); - return -ENOSPC; - } + index = ida_alloc_max(&fsi->allocated_ptys, fsi->mount_opts.max - 1, + GFP_KERNEL); - ida_ret = ida_get_new(&fsi->allocated_ptys, &index); - if (ida_ret < 0) { - mutex_unlock(&allocated_ptys_lock); - if (ida_ret == -EAGAIN) - goto retry; - return -EIO; - } - - if (index >= fsi->mount_opts.max) { - ida_remove(&fsi->allocated_ptys, index); - mutex_unlock(&allocated_ptys_lock); - return -ENOSPC; - } - pty_count++; - mutex_unlock(&allocated_ptys_lock); +out: + if (index < 0) + atomic_dec(&pty_count); return index; } void devpts_kill_index(struct pts_fs_info *fsi, int idx) { - mutex_lock(&allocated_ptys_lock); - ida_remove(&fsi->allocated_ptys, idx); - pty_count--; - mutex_unlock(&allocated_ptys_lock); + ida_free(&fsi->allocated_ptys, idx); + atomic_dec(&pty_count); } /**