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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
percpu_test.c 
#include <linux/module.h>

/* validate @native and @pcp counter values match @expected */
#define CHECK(native, pcp, expected)                                    \
	do {                                                            \
		WARN((native) != (expected),                            \
		     "raw %ld (0x%lx) != expected %lld (0x%llx)",	\
		     (native), (native),				\
		     (long long)(expected), (long long)(expected));	\
		WARN(__this_cpu_read(pcp) != (expected),                \
		     "pcp %ld (0x%lx) != expected %lld (0x%llx)",	\
		     __this_cpu_read(pcp), __this_cpu_read(pcp),	\
		     (long long)(expected), (long long)(expected));	\
	} while (0)

static DEFINE_PER_CPU(long, long_counter);
static DEFINE_PER_CPU(unsigned long, ulong_counter);

static int __init percpu_test_init(void)
{
	/*
	 * volatile prevents compiler from optimizing it uses, otherwise the
	 * +ul_one/-ul_one below would replace with inc/dec instructions.
	 */
	volatile unsigned int ui_one = 1;
	long l = 0;
	unsigned long ul = 0;

	pr_info("percpu test start\n");

	preempt_disable();

	l += -1;
	__this_cpu_add(long_counter, -1);
	CHECK(l, long_counter, -1);

	l += 1;
	__this_cpu_add(long_counter, 1);
	CHECK(l, long_counter, 0);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += 1UL;
	__this_cpu_add(ulong_counter, 1UL);
	CHECK(ul, ulong_counter, 1);

	ul += -1UL;
	__this_cpu_add(ulong_counter, -1UL);
	CHECK(ul, ulong_counter, 0);

	ul += -(unsigned long)1;
	__this_cpu_add(ulong_counter, -(unsigned long)1);
	CHECK(ul, ulong_counter, -1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= 1;
	__this_cpu_dec(ulong_counter);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, 0xffffffff);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);


	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	__this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, 1);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);
	CHECK(l, long_counter, ULONG_MAX);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += ui_one;
	__this_cpu_add(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= ui_one;
	__this_cpu_sub(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	ul = 3;
	__this_cpu_write(ulong_counter, 3);

	ul = this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 2);

	ul = __this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	preempt_enable();

	pr_info("percpu test done\n");
	return -EAGAIN;  /* Fail will directly unload the module */
}

static void __exit percpu_test_exit(void)
{
}

module_init(percpu_test_init)
module_exit(percpu_test_exit)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Greg Thelen");
MODULE_DESCRIPTION("percpu operations test");
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