tty: audit: do not use N_TTY_BUF_SIZE

N_TTY_BUF_SIZE -- as the name suggests -- is the N_TTY's buffer size.
There is no reason to couple that to audit's buffer size, so define an
own TTY_AUDIT_BUF_SIZE macro (with the same size).

N_TTY_BUF_SIZE is private and will be moved to n_tty.c later.

Signed-off-by: Jiri Slaby (SUSE) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/tty_audit.c

···
 #include <linux/tty.h>
 #include "tty.h"
 
+#define TTY_AUDIT_BUF_SIZE	4096
+
 struct tty_audit_buf {
 	struct mutex mutex;	/* Protects all data below */
 	dev_t dev;		/* The TTY which the data is from */
 	bool icanon;
 	size_t valid;
-	u8 *data;		/* Allocated size N_TTY_BUF_SIZE */
+	u8 *data;		/* Allocated size TTY_AUDIT_BUF_SIZE */
 };
 
 static struct tty_audit_buf *tty_audit_buf_ref(void)
···
 	if (!buf)
 		goto err;
 
-	buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
+	buf->data = kmalloc(TTY_AUDIT_BUF_SIZE, GFP_KERNEL);
 	if (!buf->data)
 		goto err_buf;
 
···
 	do {
 		size_t run;
 
-		run = N_TTY_BUF_SIZE - buf->valid;
+		run = TTY_AUDIT_BUF_SIZE - buf->valid;
 		if (run > size)
 			run = size;
 		memcpy(buf->data + buf->valid, data, run);
 		buf->valid += run;
 		data += run;
 		size -= run;
-		if (buf->valid == N_TTY_BUF_SIZE)
+		if (buf->valid == TTY_AUDIT_BUF_SIZE)
 			tty_audit_buf_push(buf);
 	} while (size != 0);
 	mutex_unlock(&buf->mutex);