[PATCH 3/5] tty: n_hdlc: remove HDLC_MAGIC

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According to Greg, in the context of magic numbers as defined in
magic-number.rst, "the tty layer should not need this and I'll gladly
take patches"

Ref: https://lore.kernel.org/linux-doc/YyMlovoskUcHLEb7@xxxxxxxxx/
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx>
---
 Documentation/process/magic-number.rst        |  1 -
 .../it_IT/process/magic-number.rst            |  1 -
 .../zh_CN/process/magic-number.rst            |  1 -
 .../zh_TW/process/magic-number.rst            |  1 -
 drivers/tty/n_hdlc.c                          | 27 -------------------
 5 files changed, 31 deletions(-)

diff --git a/Documentation/process/magic-number.rst b/Documentation/process/magic-number.rst
index d47799ba0ca4..fdaa3e4b1953 100644
--- a/Documentation/process/magic-number.rst
+++ b/Documentation/process/magic-number.rst
@@ -71,7 +71,6 @@ Magic Name            Number           Structure                File
 PG_MAGIC              'P'              pg_{read,write}_hdr      ``include/linux/pg.h``
 CMAGIC                0x0111           user                     ``include/linux/a.out.h``
 MKISS_DRIVER_MAGIC    0x04bf           mkiss_channel            ``drivers/net/mkiss.h``
-HDLC_MAGIC            0x239e           n_hdlc                   ``drivers/char/n_hdlc.c``
 APM_BIOS_MAGIC        0x4101           apm_user                 ``arch/x86/kernel/apm_32.c``
 DB_MAGIC              0x4442           fc_info                  ``drivers/net/iph5526_novram.c``
 DL_MAGIC              0x444d           fc_info                  ``drivers/net/iph5526_novram.c``
diff --git a/Documentation/translations/it_IT/process/magic-number.rst b/Documentation/translations/it_IT/process/magic-number.rst
index 24022ab52ebb..1898f98875de 100644
--- a/Documentation/translations/it_IT/process/magic-number.rst
+++ b/Documentation/translations/it_IT/process/magic-number.rst
@@ -77,7 +77,6 @@ Nome magico           Numero           Struttura                File
 PG_MAGIC              'P'              pg_{read,write}_hdr      ``include/linux/pg.h``
 CMAGIC                0x0111           user                     ``include/linux/a.out.h``
 MKISS_DRIVER_MAGIC    0x04bf           mkiss_channel            ``drivers/net/mkiss.h``
-HDLC_MAGIC            0x239e           n_hdlc                   ``drivers/char/n_hdlc.c``
 APM_BIOS_MAGIC        0x4101           apm_user                 ``arch/x86/kernel/apm_32.c``
 DB_MAGIC              0x4442           fc_info                  ``drivers/net/iph5526_novram.c``
 DL_MAGIC              0x444d           fc_info                  ``drivers/net/iph5526_novram.c``
diff --git a/Documentation/translations/zh_CN/process/magic-number.rst b/Documentation/translations/zh_CN/process/magic-number.rst
index 811804996283..911cdaeaf698 100644
--- a/Documentation/translations/zh_CN/process/magic-number.rst
+++ b/Documentation/translations/zh_CN/process/magic-number.rst
@@ -60,7 +60,6 @@ Linux 魔术数
 PG_MAGIC              'P'              pg_{read,write}_hdr      ``include/linux/pg.h``
 CMAGIC                0x0111           user                     ``include/linux/a.out.h``
 MKISS_DRIVER_MAGIC    0x04bf           mkiss_channel            ``drivers/net/mkiss.h``
-HDLC_MAGIC            0x239e           n_hdlc                   ``drivers/char/n_hdlc.c``
 APM_BIOS_MAGIC        0x4101           apm_user                 ``arch/x86/kernel/apm_32.c``
 DB_MAGIC              0x4442           fc_info                  ``drivers/net/iph5526_novram.c``
 DL_MAGIC              0x444d           fc_info                  ``drivers/net/iph5526_novram.c``
diff --git a/Documentation/translations/zh_TW/process/magic-number.rst b/Documentation/translations/zh_TW/process/magic-number.rst
index 8e37e00590f5..ac87f188235f 100644
--- a/Documentation/translations/zh_TW/process/magic-number.rst
+++ b/Documentation/translations/zh_TW/process/magic-number.rst
@@ -63,7 +63,6 @@ Linux 魔術數
 PG_MAGIC              'P'              pg_{read,write}_hdr      ``include/linux/pg.h``
 CMAGIC                0x0111           user                     ``include/linux/a.out.h``
 MKISS_DRIVER_MAGIC    0x04bf           mkiss_channel            ``drivers/net/mkiss.h``
-HDLC_MAGIC            0x239e           n_hdlc                   ``drivers/char/n_hdlc.c``
 APM_BIOS_MAGIC        0x4101           apm_user                 ``arch/x86/kernel/apm_32.c``
 DB_MAGIC              0x4442           fc_info                  ``drivers/net/iph5526_novram.c``
 DL_MAGIC              0x444d           fc_info                  ``drivers/net/iph5526_novram.c``
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 94c1ec2dd754..b5aa27051119 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -76,8 +76,6 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#define HDLC_MAGIC 0x239e
-
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -124,7 +122,6 @@ struct n_hdlc_buf_list {
 
 /**
  * struct n_hdlc - per device instance data structure
- * @magic: magic value for structure
  * @tbusy: reentrancy flag for tx wakeup code
  * @woke_up: tx wakeup needs to be run again as it was called while @tbusy
  * @tx_buf_list: list of pending transmit frame buffers
@@ -133,7 +130,6 @@ struct n_hdlc_buf_list {
  * @rx_free_buf_list: list unused received frame buffers
  */
 struct n_hdlc {
-	int			magic;
 	bool			tbusy;
 	bool			woke_up;
 	struct n_hdlc_buf_list	tx_buf_list;
@@ -200,10 +196,6 @@ static void n_hdlc_tty_close(struct tty_struct *tty)
 {
 	struct n_hdlc *n_hdlc = tty->disc_data;
 
-	if (n_hdlc->magic != HDLC_MAGIC) {
-		pr_warn("n_hdlc: trying to close unopened tty!\n");
-		return;
-	}
 #if defined(TTY_NO_WRITE_SPLIT)
 	clear_bit(TTY_NO_WRITE_SPLIT, &tty->flags);
 #endif
@@ -386,12 +378,6 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
 
 	pr_debug("%s() called count=%d\n", __func__, count);
 
-	/* verify line is using HDLC discipline */
-	if (n_hdlc->magic != HDLC_MAGIC) {
-		pr_err("line not using HDLC discipline\n");
-		return;
-	}
-
 	if (count > maxframe) {
 		pr_debug("rx count>maxframesize, data discarded\n");
 		return;
@@ -542,9 +528,6 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
 
 	pr_debug("%s() called count=%zd\n", __func__, count);
 
-	if (n_hdlc->magic != HDLC_MAGIC)
-		return -EIO;
-
 	/* verify frame size */
 	if (count > maxframe) {
 		pr_debug("%s: truncating user packet from %zu to %d\n",
@@ -609,10 +592,6 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 
 	pr_debug("%s() called %d\n", __func__, cmd);
 
-	/* Verify the status of the device */
-	if (n_hdlc->magic != HDLC_MAGIC)
-		return -EBADF;
-
 	switch (cmd) {
 	case FIONREAD:
 		/* report count of read data available */
@@ -673,9 +652,6 @@ 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->magic != HDLC_MAGIC)
-		return 0;
-
 	/*
 	 * queue the current process into any wait queue that may awaken in the
 	 * future (read and write)
@@ -739,9 +715,6 @@ static struct n_hdlc *n_hdlc_alloc(void)
 	n_hdlc_alloc_buf(&n_hdlc->rx_free_buf_list, DEFAULT_RX_BUF_COUNT, "rx");
 	n_hdlc_alloc_buf(&n_hdlc->tx_free_buf_list, DEFAULT_TX_BUF_COUNT, "tx");
 
-	/* Initialize the control block */
-	n_hdlc->magic  = HDLC_MAGIC;
-
 	return n_hdlc;
 
 }	/* end of n_hdlc_alloc() */
-- 
2.30.2

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