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Commit bf7a06bc authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

vt: remove bogus lock dropping 



For hysterical raisins the vt layer drops and retakes locks in the write
method. This is a left over from the days when user/kernel data was passed
directly to the tty not pre-buffered.

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15582d36

drivers/char/vt.c

+0 −18
Original line number Diff line number Diff line
@@ -2136,27 +2136,9 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 
	    release_console_sem();

	    return 0;

	}

	release_console_sem();



	orig_buf = buf;

	orig_count = count;



	/* At this point 'buf' is guaranteed to be a kernel buffer

	 * and therefore no access to userspace (and therefore sleeping)

	 * will be needed.  The con_buf_mtx serializes all tty based

	 * console rendering and vcs write/read operations.  We hold

	 * the console spinlock during the entire write.

	 */



	acquire_console_sem();



	vc = tty->driver_data;

	if (vc == NULL) {

		printk(KERN_ERR "vt: argh, driver_data _became_ NULL !\n");

		release_console_sem();

		goto out;

	}



	himask = vc->vc_hi_font_mask;

	charmask = himask ? 0x1ff : 0xff;