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author | Matthew Wilcox <willy@infradead.org> | 2018-06-11 15:17:58 -0400 |
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committer | Matthew Wilcox <willy@infradead.org> | 2018-08-21 23:54:17 -0400 |
commit | 0f0a0e54a2a15174535349db3a22355a6b1cf5fa (patch) | |
tree | 6e011cfaeb3d11f8cab3d0581fad70b6afef7277 /fs/devpts | |
parent | 169b480e4c8b7409119458ebfb755283a5fc9826 (diff) | |
download | lwn-0f0a0e54a2a15174535349db3a22355a6b1cf5fa.tar.gz lwn-0f0a0e54a2a15174535349db3a22355a6b1cf5fa.zip |
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 <willy@infradead.org>
Diffstat (limited to 'fs/devpts')
-rw-r--r-- | fs/devpts/inode.c | 47 |
1 files changed, 13 insertions, 34 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; - -retry: - if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) - return -ENOMEM; - - mutex_lock(&allocated_ptys_lock); - if (pty_count >= (pty_limit - - (fsi->mount_opts.reserve ? 0 : pty_reserve))) { - mutex_unlock(&allocated_ptys_lock); - return -ENOSPC; - } + int index = -ENOSPC; - 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 (atomic_inc_return(&pty_count) >= (pty_limit - + (fsi->mount_opts.reserve ? 0 : pty_reserve))) + goto out; - 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); + index = ida_alloc_max(&fsi->allocated_ptys, fsi->mount_opts.max - 1, + GFP_KERNEL); + +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); } /** |