Revision 5befb98b30cce19bdf2221ea48c39f1fec5c4568 authored by Linus Torvalds on 24 August 2013, 18:33:21 UTC, committed by Linus Torvalds on 24 August 2013, 18:33:21 UTC
Pull SCSI fixes from James Bottomley:
 "This is a set of small bug fixes for lpfc and zfcp and a fix for a
  fairly nasty bug in sg where a process which cancels I/O completes in
  a kernel thread which would then try to write back to the now gone
  userspace and end up writing to a random kernel address instead"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] zfcp: remove access control tables interface (keep sysfs files)
  [SCSI] zfcp: fix schedule-inside-lock in scsi_device list loops
  [SCSI] zfcp: fix lock imbalance by reworking request queue locking
  [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
  [SCSI] lpfc: Don't force CONFIG_GENERIC_CSUM on
2 parent s b0f55f2 + b5dc3c4
Raw File
user-return-notifier.c

#include <linux/user-return-notifier.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/export.h>

static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);

/*
 * Request a notification when the current cpu returns to userspace.  Must be
 * called in atomic context.  The notifier will also be called in atomic
 * context.
 */
void user_return_notifier_register(struct user_return_notifier *urn)
{
	set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
	hlist_add_head(&urn->link, &__get_cpu_var(return_notifier_list));
}
EXPORT_SYMBOL_GPL(user_return_notifier_register);

/*
 * Removes a registered user return notifier.  Must be called from atomic
 * context, and from the same cpu registration occurred in.
 */
void user_return_notifier_unregister(struct user_return_notifier *urn)
{
	hlist_del(&urn->link);
	if (hlist_empty(&__get_cpu_var(return_notifier_list)))
		clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
}
EXPORT_SYMBOL_GPL(user_return_notifier_unregister);

/* Calls registered user return notifiers */
void fire_user_return_notifiers(void)
{
	struct user_return_notifier *urn;
	struct hlist_node *tmp2;
	struct hlist_head *head;

	head = &get_cpu_var(return_notifier_list);
	hlist_for_each_entry_safe(urn, tmp2, head, link)
		urn->on_user_return(urn);
	put_cpu_var(return_notifier_list);
}
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