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From: Jiri Slaby <jslaby@suse.cz>
To: gregkh@linuxfoundation.org
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH 14/24] n_hdlc: remove checking of n_hdlc
Date: Wed, 19 Feb 2020 09:41:08 +0100	[thread overview]
Message-ID: <20200219084118.26491-14-jslaby@suse.cz> (raw)
In-Reply-To: <20200219084118.26491-1-jslaby@suse.cz>

We got rid of backup_tty recently. Also, the tty layer ensures not to
call other ldisc hooks after ldisc close. That means, all those tests
are superfluous now so remove them.

Note that we remove the magic check in write after schedule too. The tty
cannot change during schedule.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/n_hdlc.c | 32 +++-----------------------------
 1 file changed, 3 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 2ac702974b57..2709d18364eb 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -227,9 +227,6 @@ static void n_hdlc_tty_close(struct tty_struct *tty)
 {
 	struct n_hdlc *n_hdlc = tty->disc_data;
 
-	if (!n_hdlc)
-		return;
-
 	if (n_hdlc->magic != HDLC_MAGIC) {
 		printk(KERN_WARNING "n_hdlc: trying to close unopened tty!\n");
 		return;
@@ -383,11 +380,7 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty)
 {
 	struct n_hdlc *n_hdlc = tty->disc_data;
 
-	if (!n_hdlc)
-		return;
-
 	n_hdlc_send_frames (n_hdlc, tty);
-		
 }	/* end of n_hdlc_tty_wakeup() */
 
 /**
@@ -409,10 +402,6 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
 	pr_debug("%s(%d)%s() called count=%d\n",
 			__FILE__, __LINE__, __func__, count);
 
-	/* This can happen if stuff comes in on the backup tty */
-	if (!n_hdlc)
-		return;
-		
 	/* verify line is using HDLC discipline */
 	if (n_hdlc->magic != HDLC_MAGIC) {
 		printk("%s(%d) line not using HDLC discipline\n",
@@ -473,10 +462,6 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
 	struct n_hdlc_buf *rbuf;
 	DECLARE_WAITQUEUE(wait, current);
 
-	/* Validate the pointers */
-	if (!n_hdlc)
-		return -EIO;
-
 	/* verify user access to buffer */
 	if (!access_ok(buf, nr)) {
 		printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user "
@@ -558,10 +543,6 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
 	pr_debug("%s(%d)%s() called count=%zd\n", __FILE__, __LINE__, __func__,
 			count);
 
-	/* Verify pointers */
-	if (!n_hdlc)
-		return -EIO;
-
 	if (n_hdlc->magic != HDLC_MAGIC)
 		return -EIO;
 
@@ -586,14 +567,7 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
 			break;
 		}
 		schedule();
-			
-		n_hdlc = tty->disc_data;
-		if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) {
-			printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
-			error = -EIO;
-			break;
-		}
-			
+
 		if (signal_pending(current)) {
 			error = -EINTR;
 			break;
@@ -638,7 +612,7 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
 	pr_debug("%s(%d)%s() called %d\n", __FILE__, __LINE__, __func__, cmd);
 
 	/* Verify the status of the device */
-	if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
+	if (n_hdlc->magic != HDLC_MAGIC)
 		return -EBADF;
 
 	switch (cmd) {
@@ -701,7 +675,7 @@ static __poll_t n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
 	struct n_hdlc *n_hdlc = tty->disc_data;
 	__poll_t mask = 0;
 
-	if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
+	if (n_hdlc->magic != HDLC_MAGIC)
 		return 0;
 
 	/*
-- 
2.25.0


  parent reply	other threads:[~2020-02-19  8:42 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19  8:40 [PATCH 01/24] n_hdlc: remove tracing debug prints Jiri Slaby
2020-02-19  8:40 ` [PATCH 02/24] n_hdlc: remove unused macros Jiri Slaby
2020-02-19  8:40 ` [PATCH 03/24] n_hdlc: convert debuglevel use to pr_debug Jiri Slaby
2020-02-19 12:20   ` Joe Perches
2020-02-20 12:45     ` Greg KH
2020-02-21  8:16     ` Jiri Slaby
2020-02-19  8:40 ` [PATCH 04/24] n_hdlc: put init/exit strings directly to prints Jiri Slaby
2020-02-19  8:40 ` [PATCH 05/24] n_hdlc: cleanup messages during registration Jiri Slaby
2020-02-19  8:41 ` [PATCH 06/24] n_hdlc: use clamp() for maxframe Jiri Slaby
2020-02-19  8:41 ` [PATCH 07/24] n_hdlc: simplify freeing of buffer list Jiri Slaby
2020-02-19  8:41 ` [PATCH 08/24] n_hdlc: invert conditions in n_hdlc_tty_close and n_hdlc_tty_poll Jiri Slaby
2020-02-19  8:41 ` [PATCH 09/24] n_hdlc: remove unused flags Jiri Slaby
2020-02-19  8:41 ` [PATCH 10/24] n_hdlc: remove unused backup_tty Jiri Slaby
2020-02-19  8:41 ` [PATCH 11/24] n_hdlc: expand tty2n_hdlc macro Jiri Slaby
2020-02-19  8:41 ` [PATCH 12/24] n_hdlc: inline n_hdlc_release Jiri Slaby
2020-02-19  8:41 ` [PATCH 13/24] n_hdlc: remove cached tty Jiri Slaby
2020-02-19  8:41 ` Jiri Slaby [this message]
2020-02-19  8:41 ` [PATCH 15/24] n_hdlc: add helper for buffers allocation Jiri Slaby
2020-02-19  8:41 ` [PATCH 16/24] n_hdlc: move tty_ldisc_ops to the bottom Jiri Slaby
2020-02-19  8:41 ` [PATCH 17/24] n_hdlc: switch tbusy and woke_up to bools Jiri Slaby
2020-02-19  8:41 ` [PATCH 18/24] n_hdlc: remove unneeded ifdef Jiri Slaby
2020-02-19  8:41 ` [PATCH 19/24] n_hdlc: use __func__ and pr_ print helpers Jiri Slaby
2020-02-19  8:41 ` [PATCH 20/24] n_hdlc: remove useless whitespace at line wraps Jiri Slaby
2020-02-19  8:41 ` [PATCH 21/24] n_hdlc: remove spaces between function name and ( Jiri Slaby
2020-02-19  8:41 ` [PATCH 22/24] n_hdlc: add missing spaces after commas Jiri Slaby
2020-02-19  8:41 ` [PATCH 23/24] n_hdlc: fix whitespace around binary operators Jiri Slaby
2020-02-19  8:41 ` [PATCH 24/24] n_hdlc: wrap a comment properly Jiri Slaby

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