Messages in this thread Patch in this message | | | Date | Thu, 17 Apr 2008 14:17:25 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH]: Factor out PTY index allocation |
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On Wed, 16 Apr 2008 15:17:23 -0700 sukadev@us.ibm.com wrote:
> Factor out the code used to allocate/free a pts index into new interfaces, > devpts_new_index() and devpts_kill_index(). This localizes the external > data structures used in managing the pts indices.
err...
> - mutex_lock(&allocated_ptys_lock); > + down(&allocated_ptys_lock);
Why the mutex-to-semaphore conversion?
--- a/fs/devpts/inode.c~devpts-factor-out-pty-index-allocation-fix +++ a/fs/devpts/inode.c @@ -17,6 +17,7 @@ #include <linux/namei.h> #include <linux/mount.h> #include <linux/tty.h> +#include <linux/mutex.h> #include <linux/idr.h> #include <linux/devpts_fs.h> #include <linux/parser.h> @@ -29,7 +30,7 @@ extern int pty_limit; /* Config limit on Unix98 ptys */ static DEFINE_IDR(allocated_ptys); -static DECLARE_MUTEX(allocated_ptys_lock); +static DEFINE_MUTEX(allocated_ptys_lock); static struct vfsmount *devpts_mnt; static struct dentry *devpts_root; @@ -186,10 +187,10 @@ retry: return -ENOMEM; } - down(&allocated_ptys_lock); + mutex_lock(&allocated_ptys_lock); idr_ret = idr_get_new(&allocated_ptys, NULL, &index); if (idr_ret < 0) { - up(&allocated_ptys_lock); + mutex_unlock(&allocated_ptys_lock); if (idr_ret == -EAGAIN) goto retry; return -EIO; @@ -197,18 +198,18 @@ retry: if (index >= pty_limit) { idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); + mutex_unlock(&allocated_ptys_lock); return -EIO; } - up(&allocated_ptys_lock); + mutex_unlock(&allocated_ptys_lock); return index; } void devpts_kill_index(int idx) { - down(&allocated_ptys_lock); + mutex_lock(&allocated_ptys_lock); idr_remove(&allocated_ptys, idx); - up(&allocated_ptys_lock); + mutex_unlock(&allocated_ptys_lock); } int devpts_pty_new(struct tty_struct *tty) _
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