Merge tag 'staging-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging/IIO driver updates from Greg KH:
 "Here is the big staging and IIO driver update for 4.14-rc1.

  Lots of staging driver fixes and cleanups, including some reorginizing
  of the lustre header files to try to impose some sanity on what is,
  and what is not, the uapi for that filesystem.

  There are some tty core changes in here as well, as the speakup
  drivers need them, and that's ok with me, they are sane and the
  speakup code is getting nicer because of it.

  There is also the addition of the obiligatory new wifi driver, just
  because it has been a release or two since we added our last one...

  Other than that, lots and lots of small coding style fixes, as usual.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (612 commits)
  staging:rtl8188eu:core Fix remove unneccessary else block
  staging: typec: fusb302: make structure fusb302_psy_desc static
  staging: unisys: visorbus: make two functions static
  staging: fsl-dpaa2/eth: fix off-by-one FD ctrl bitmaks
  staging: r8822be: Simplify deinit_priv()
  staging: r8822be: Remove some dead code
  staging: vboxvideo: Use CONFIG_DRM_KMS_FB_HELPER to check for fbdefio availability
  staging:rtl8188eu Fix comparison to NULL
  staging: rts5208: rename mmc_ddr_tunning_rx_cmd to mmc_ddr_tuning_rx_cmd
  Staging: Pi433: style fix - tabs and spaces
  staging: pi433: fix spelling mistake: "preample" -> "preamble"
  staging:rtl8188eu:core Fix Code Indent
  staging: typec: fusb302: Export current-limit through a power_supply class dev
  staging: typec: fusb302: Add support for USB2 charger detection through extcon
  staging: typec: fusb302: Use client->irq as irq if set
  staging: typec: fusb302: Get max snk mv/ma/mw from device-properties
  staging: typec: fusb302: Set max supply voltage to 5V
  staging: typec: tcpm: Add get_current_limit tcpc_dev callback
  staging:rtl8188eu Use __func__ instead of function name
  staging: lustre: coding style fixes found by checkpatch.pl
  ...

1 files changed, 96 insertions, 7 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index da912517d295..94cccb6efa32 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -280,7 +280,7 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
 {
 #ifdef CHECK_TTY_COUNT
 	struct list_head *p;
-	int count = 0;
+	int count = 0, kopen_count = 0;
 
 	spin_lock(&tty->files_lock);
 	list_for_each(p, &tty->tty_files) {
@@ -291,10 +291,12 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
 	    tty->driver->subtype == PTY_TYPE_SLAVE &&
 	    tty->link && tty->link->count)
 		count++;
-	if (tty->count != count) {
-		tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
-			 routine, tty->count, count);
-		return count;
+	if (tty_port_kopened(tty->port))
+		kopen_count++;
+	if (tty->count != (count + kopen_count)) {
+		tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
+			 routine, tty->count, count, kopen_count);
+		return (count + kopen_count);
 	}
 #endif
 	return 0;
@@ -1522,6 +1524,38 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
 }
 
 /**
+ *      tty_kclose      -       closes tty opened by tty_kopen
+ *      @tty: tty device
+ *
+ *      Performs the final steps to release and free a tty device. It is the
+ *      same as tty_release_struct except that it also resets TTY_PORT_KOPENED
+ *      flag on tty->port.
+ */
+void tty_kclose(struct tty_struct *tty)
+{
+	/*
+	 * Ask the line discipline code to release its structures
+	 */
+	tty_ldisc_release(tty);
+
+	/* Wait for pending work before tty destruction commmences */
+	tty_flush_works(tty);
+
+	tty_debug_hangup(tty, "freeing structure\n");
+	/*
+	 * The release_tty function takes care of the details of clearing
+	 * the slots and preserving the termios structure. The tty_unlock_pair
+	 * should be safe as we keep a kref while the tty is locked (so the
+	 * unlock never unlocks a freed tty).
+	 */
+	mutex_lock(&tty_mutex);
+	tty_port_set_kopened(tty->port, 0);
+	release_tty(tty, tty->index);
+	mutex_unlock(&tty_mutex);
+}
+EXPORT_SYMBOL_GPL(tty_kclose);
+
+/**
  *	tty_release_struct	-	release a tty struct
  *	@tty: tty device
  *	@idx: index of the tty
@@ -1795,6 +1829,56 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 }
 
 /**
+ *	tty_kopen	-	open a tty device for kernel
+ *	@device: dev_t of device to open
+ *
+ *	Opens tty exclusively for kernel. Performs the driver lookup,
+ *	makes sure it's not already opened and performs the first-time
+ *	tty initialization.
+ *
+ *	Returns the locked initialized &tty_struct
+ *
+ *	Claims the global tty_mutex to serialize:
+ *	  - concurrent first-time tty initialization
+ *	  - concurrent tty driver removal w/ lookup
+ *	  - concurrent tty removal from driver table
+ */
+struct tty_struct *tty_kopen(dev_t device)
+{
+	struct tty_struct *tty;
+	struct tty_driver *driver = NULL;
+	int index = -1;
+
+	mutex_lock(&tty_mutex);
+	driver = tty_lookup_driver(device, NULL, &index);
+	if (IS_ERR(driver)) {
+		mutex_unlock(&tty_mutex);
+		return ERR_CAST(driver);
+	}
+
+	/* check whether we're reopening an existing tty */
+	tty = tty_driver_lookup_tty(driver, NULL, index);
+	if (IS_ERR(tty))
+		goto out;
+
+	if (tty) {
+		/* drop kref from tty_driver_lookup_tty() */
+		tty_kref_put(tty);
+		tty = ERR_PTR(-EBUSY);
+	} else { /* tty_init_dev returns tty with the tty_lock held */
+		tty = tty_init_dev(driver, index);
+		if (IS_ERR(tty))
+			goto out;
+		tty_port_set_kopened(tty->port, 1);
+	}
+out:
+	mutex_unlock(&tty_mutex);
+	tty_driver_kref_put(driver);
+	return tty;
+}
+EXPORT_SYMBOL_GPL(tty_kopen);
+
+/**
  *	tty_open_by_driver	-	open a tty device
  *	@device: dev_t of device to open
  *	@inode: inode of device file
@@ -1810,7 +1894,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
  *	  - concurrent tty driver removal w/ lookup
  *	  - concurrent tty removal from driver table
  */
-struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
+static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
 					     struct file *filp)
 {
 	struct tty_struct *tty;
@@ -1833,6 +1917,12 @@ struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
 	}
 
 	if (tty) {
+		if (tty_port_kopened(tty->port)) {
+			tty_kref_put(tty);
+			mutex_unlock(&tty_mutex);
+			tty = ERR_PTR(-EBUSY);
+			goto out;
+		}
 		mutex_unlock(&tty_mutex);
 		retval = tty_lock_interruptible(tty);
 		tty_kref_put(tty);  /* drop kref from tty_driver_lookup_tty() */
@@ -1855,7 +1945,6 @@ out:
 	tty_driver_kref_put(driver);
 	return tty;
 }
-EXPORT_SYMBOL_GPL(tty_open_by_driver);
 
 /**
  *	tty_open		-	open a tty device