lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20060826203142.GA333@oleg>
Date:	Sun, 27 Aug 2006 00:31:42 +0400
From:	Oleg Nesterov <oleg@...sign.ru>
To:	Jens Axboe <axboe@...e.de>
Cc:	Andrew Morton <akpm@...l.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] exit_io_context: don't disable irqs

We don't need to disable irqs to clear current->io_context, it is protected
by ->alloc_lock. Even IF it was possible to submit I/O from IRQ on behalf of
current this irq_disable() can't help: current_io_context() will re-instantiate
->io_context after irq_enable().

We don't need task_lock() or local_irq_disable() to clear ioc->task. This can't
prevent other CPUs from playing with our io_context anyway.

Signed-off-by: Oleg Nesterov <oleg@...sign.ru>

--- 2.6.18-rc4/block/ll_rw_blk.c~6_exit	2006-08-27 00:10:53.000000000 +0400
+++ 2.6.18-rc4/block/ll_rw_blk.c	2006-08-27 00:11:47.000000000 +0400
@@ -3580,25 +3580,22 @@ EXPORT_SYMBOL(put_io_context);
 /* Called by the exitting task */
 void exit_io_context(void)
 {
-	unsigned long flags;
 	struct io_context *ioc;
 	struct cfq_io_context *cic;
 
-	local_irq_save(flags);
 	task_lock(current);
 	ioc = current->io_context;
 	current->io_context = NULL;
-	ioc->task = NULL;
 	task_unlock(current);
-	local_irq_restore(flags);
 
+	ioc->task = NULL;
 	if (ioc->aic && ioc->aic->exit)
 		ioc->aic->exit(ioc->aic);
 	if (ioc->cic_root.rb_node != NULL) {
 		cic = rb_entry(rb_first(&ioc->cic_root), struct cfq_io_context, rb_node);
 		cic->exit(ioc);
 	}
- 
+
 	put_io_context(ioc);
 }
 

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ