summaryrefslogtreecommitdiff
path: root/include/xen/xen.h
blob: f0f0252cff9aab2442e8df64430ec118a2f391aa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
#ifndef _XEN_XEN_H
#define _XEN_XEN_H

enum xen_domain_type {
	XEN_NATIVE,		/* running on bare hardware    */
	XEN_PV_DOMAIN,		/* running in a PV domain      */
	XEN_HVM_DOMAIN,		/* running in a Xen hvm domain */
};

#ifdef CONFIG_XEN
extern enum xen_domain_type xen_domain_type;
#else
#define xen_domain_type		XEN_NATIVE
#endif

#define xen_domain()		(xen_domain_type != XEN_NATIVE)
#define xen_pv_domain()		(xen_domain() &&			\
				 xen_domain_type == XEN_PV_DOMAIN)
#define xen_hvm_domain()	(xen_domain() &&			\
				 xen_domain_type == XEN_HVM_DOMAIN)

#ifdef CONFIG_XEN_DOM0
#include <xen/interface/xen.h>
#include <asm/xen/hypervisor.h>

#define xen_initial_domain()	(xen_domain() && \
				 xen_start_info && xen_start_info->flags & SIF_INITDOMAIN)
#else  /* !CONFIG_XEN_DOM0 */
#define xen_initial_domain()	(0)
#endif	/* CONFIG_XEN_DOM0 */

#ifdef CONFIG_XEN_PVH
/* This functionality exists only for x86. The XEN_PVHVM support exists
 * only in x86 world - hence on ARM it will be always disabled.
 * N.B. ARM guests are neither PV nor HVM nor PVHVM.
 * It's a bit like PVH but is different also (it's further towards the H
 * end of the spectrum than even PVH).
 */
#include <xen/features.h>
#define xen_pvh_domain() (xen_pv_domain() && \
			  xen_feature(XENFEAT_auto_translated_physmap))
#else
#define xen_pvh_domain()	(0)
#endif
#endif	/* _XEN_XEN_H */
es is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'include/dt-bindings/phy')