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Commit f18f9498e90327b9b0e245e191029e6e1996d203

Authored by Alan Cox
Committed by Greg Kroah-Hartman
1 parent eeb89d918c
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

tty: Push the lock down further into the ldisc code 

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Showing 2 changed files with 9 additions and 5 deletions Side-by-side Diff

drivers/char/tty_io.c
Diff comments   View file @ f18f949
... ... @@ -1347,9 +1347,7 @@
1347 1347 * If we fail here just call release_tty to clean up. No need
1348 1348 * to decrement the use counts, as release_tty doesn't care.
1349 1349 */
1350   - lock_kernel();
1351 1350 retval = tty_ldisc_setup(tty, tty->link);
1352   - unlock_kernel();
1353 1351 if (retval)
1354 1352 goto release_mem_out;
1355 1353 return tty;
drivers/char/tty_ldisc.c
Diff comments   View file @ f18f949
... ... @@ -445,8 +445,14 @@
445 445 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
446 446 {
447 447 WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));
448   - if (ld->ops->open)
449   - return ld->ops->open(tty);
  448 + if (ld->ops->open) {
  449 + int ret;
  450 + /* BKL here locks verus a hangup event */
  451 + lock_kernel();
  452 + ret = ld->ops->open(tty);
  453 + unlock_kernel();
  454 + return ret;
  455 + }
450 456 return 0;
451 457 }
452 458  
... ... @@ -566,6 +572,7 @@
566 572 return 0;
567 573 }
568 574  
  575 + unlock_kernel();
569 576 /*
570 577 * Problem: What do we do if this blocks ?
571 578 * We could deadlock here
... ... @@ -573,7 +580,6 @@
573 580  
574 581 tty_wait_until_sent(tty, 0);
575 582  
576   - unlock_kernel();
577 583 mutex_lock(&tty->ldisc_mutex);
578 584  
579 585 /*