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Revision cdce6ac277a4a1aa5316cd0cdf30fff927433917 authored by Linus Torvalds on 20 December 2014, 21:42:57 UTC, committed by Linus Torvalds on 20 December 2014, 21:42:57 UTC 
Merge tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
 
Pull SCSI update from James Bottomley:
 "This is a much shorter set of patches that were on the go but didn't
  make it in to the early pull request for the merge window.  It's
  really a set of bug fixes plus some final cleanup work on the new tag
  queue API"

* tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  storvsc: ring buffer failures may result in I/O freeze
  ipr: set scsi_level correctly for disk arrays
  ipr: add support for async scanning to speed up boot
  scsi_debug: fix missing "break;" in SDEBUG_UA_CAPACITY_CHANGED case
  scsi_debug: take sdebug_host_list_lock when changing capacity
  scsi_debug: improve driver description in Kconfig
  scsi_debug: fix compare and write errors
  qla2xxx: fix race in handling rport deletion during recovery causes panic
  scsi: blacklist RSOC for Microsoft iSCSI target devices
  scsi: fix random memory corruption with scsi-mq + T10 PI
  Revert "[SCSI] mpt3sas: Remove phys on topology change"
  Revert "[SCSI] mpt2sas: Remove phys on topology change."
  esas2r: Correct typos of "validate" in a comment
  fc: FCP_PTA_SIMPLE is 0
  ibmvfc: remove unused tag variable
  scsi: remove MSG_*_TAG defines
  scsi: remove scsi_set_tag_type
  scsi: remove scsi_get_tag_type
  scsi: never drop to untagged mode during queue ramp down
  scsi: remove ->change_queue_type method
2 parent s 5d6a546 + e617457
Raw File
dump_stack.c 
/*
 * Provide a default dump_stack() function for architectures
 * which don't implement their own.
 */

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/atomic.h>

static void __dump_stack(void)
{
	dump_stack_print_info(KERN_DEFAULT);
	show_stack(NULL, NULL);
}

/**
 * dump_stack - dump the current task information and its stack trace
 *
 * Architectures can override this implementation by implementing its own.
 */
#ifdef CONFIG_SMP
static atomic_t dump_lock = ATOMIC_INIT(-1);

asmlinkage __visible void dump_stack(void)
{
	int was_locked;
	int old;
	int cpu;

	/*
	 * Permit this cpu to perform nested stack dumps while serialising
	 * against other CPUs
	 */
	preempt_disable();

retry:
	cpu = smp_processor_id();
	old = atomic_cmpxchg(&dump_lock, -1, cpu);
	if (old == -1) {
		was_locked = 0;
	} else if (old == cpu) {
		was_locked = 1;
	} else {
		cpu_relax();
		goto retry;
	}

	__dump_stack();

	if (!was_locked)
		atomic_set(&dump_lock, -1);

	preempt_enable();
}
#else
asmlinkage __visible void dump_stack(void)
{
	__dump_stack();
}
#endif
EXPORT_SYMBOL(dump_stack);
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