RE: [PATCH][RFC] fsldma: fix performance degradation by optimizing spinlock use.

SGkgSXJhLCANCg0Kc2VlIG15IGNvbW1lbnRzIGJlbG93Lg0KDQpUaGFua3MsDQpGb3JyZXN0DQoN
Ci0tLS0tT3JpZ2luYWwgTWVzc2FnZS0tLS0tDQpGcm9tOiBJcmEgVy4gU255ZGVyIFttYWlsdG86
aXdzQG92cm8uY2FsdGVjaC5lZHVdIA0KU2VudDogMjAxMeW5tDEx5pyIMjnml6UgMDozOA0KVG86
IFNoaSBYdWVsaW4tQjI5MjM3DQpDYzogdmlub2Qua291bEBpbnRlbC5jb207IGRhbi5qLndpbGxp
YW1zQGludGVsLmNvbTsgbGludXhwcGMtZGV2QGxpc3RzLm96bGFicy5vcmc7IExpIFlhbmctUjU4
NDcyOyBsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnDQpTdWJqZWN0OiBSZTogW1BBVENIXVtS
RkNdIGZzbGRtYTogZml4IHBlcmZvcm1hbmNlIGRlZ3JhZGF0aW9uIGJ5IG9wdGltaXppbmcgc3Bp
bmxvY2sgdXNlLg0KDQpPbiBUaHUsIE5vdiAyNCwgMjAxMSBhdCAwODoxMjoyNUFNICswMDAwLCBT
aGkgWHVlbGluLUIyOTIzNyB3cm90ZToNCj4gSGkgSXJhLA0KPiANCj4gVGhhbmtzIGZvciB5b3Vy
IHJldmlldy4NCj4gDQo+IEFmdGVyIHNlY29uZCB0aG91Z2h0LCBJIHRoaW5rIHlvdXIgc2NlbmFy
aW8gbWF5IG5vdCBvY2N1ci4NCj4gQmVjYXVzZSB0aGUgY29va2llIDIwIHdlIHF1ZXJ5IG11c3Qg
YmUgcmV0dXJuZWQgYnkgZnNsX2RtYV90eF9zdWJtaXQoLi4uKSBpbiBwcmFjdGljZS4gDQo+IFdl
IG5ldmVyIHF1ZXJ5IGEgY29va2llIG5vdCByZXR1cm5lZCBieSBmc2xfZG1hX3R4X3N1Ym1pdCgu
Li4pLg0KPiANCg0KSSBhZ3JlZSBhYm91dCB0aGlzIHBhcnQuDQoNCj4gV2hlbiB3ZSBjYWxsIGZz
bF90eF9zdGF0dXMoMjApLCB0aGUgY2hhbi0+Y29tbW9uLmNvb2tpZSBpcyBkZWZpbml0ZWx5IHdy
b3RlIGFzIDIwIGFuZCBjcHUyIGNvdWxkIG5vdCByZWFkIGFzIDE5Lg0KPiANCg0KVGhpcyBpcyB3
aGF0IEkgZG9uJ3QgYWdyZWUgYWJvdXQuIEhvd2V2ZXIsIEknbSBub3QgYW4gZXhwZXJ0IG9uIENQ
VSBjYWNoZSB2cy4gbWVtb3J5IGFjY2Vzc2VzIGluIGFuIG11bHRpLXByb2Nlc3NvciBzeXN0ZW0u
IFRoZSBzZWN0aW9uIHRpdGxlZCAiQ0FDSEUgQ09IRVJFTkNZIiBpbiBEb2N1bWVudGF0aW9uL21l
bW9yeS1iYXJyaWVycy50eHQgbGVhZHMgbWUgdG8gYmVsaWV2ZSB0aGF0IHRoZSBzY2VuYXJpbyBJ
IGRlc2NyaWJlZCBpcyBwb3NzaWJsZS4NCg0KIA0KW1NoaSBYdWVsaW4tQjI5MjM3XSBJZiBxdWVy
eSBpcyB1c2VkIHdpdGhvdXQgcnVsZXMsIHlvdXIgc2NlbmFyaW8gbWF5IGhhcHBlbi4gQnV0IGlu
IERNQSB1c2FnZSBoZXJlLCB0aGUgcXVlcnkgaXMgdXNlZCBzb21ldGhpbmcgbGlrZSBzZXF1ZW50
aWFsbHkuIE9ubHkgYWZ0ZXIgY2hhbi0+Y29tbW9uLmNvb2tpZSBpcyB1cGRhdGVkIGluIGZzbF9k
bWFfdHhfc3VibWl0KC4uLikgYW5kIHJldHVybmVkLCB0aGVuIGl0IGNvdWxkIGJlIHF1ZXJpZWQu
IFNvIHlvdSBzY2VuYXJpbyB3aWxsIG5vdCBoYXBwZW4uDQoNCldoYXQgaGFwcGVucyBpZiBDUFUx
J3Mgd3JpdGUgb2YgY2hhbi0+Y29tbW9uLmNvb2tpZSBvbmx5IGdvZXMgaW50byBDUFUxJ3MgY2Fj
aGUuIEl0IG5ldmVyIG1ha2VzIGl0IHRvIG1haW4gbWVtb3J5IGJlZm9yZSBDUFUyIGZldGNoZXMg
dGhlIG9sZCB2YWx1ZSBvZiAxOS4NCiANCltTaGkgWHVlbGluLUIyOTIzN10gQXMgeW91IHNlZSwg
Y2hhbi0+Y29tbW9uLmNvb2tpZSBpcyB1cGRhdGVkIGluIGZzbF9kbWFfdHhfc3VibWl0KC4uLikg
YW5kIGVuY2xvc2VkIGJ5IHNwaW5sb2NrLiBUaGUgc3BpbmxvY2sgaW1wbGVtZW50YXRpb24gaW4g
UFBDIHdpbGwgZ3VhcmFudGVlIHRoZSBjYWNoZSBjb2hlcmVuY2UgYW1vbmcgY29yZXMsIHNvbWV0
aGluZyBsaWtlIHlvdSBjYWxsZWQgaW1wbGljaXQgc21wX21iLg0KDQpJIGRvbid0IHRoaW5rIHlv
dSBzaG91bGQgc2VlIGFueSBwZXJmb3JtYW5jZSBpbXBhY3QgZnJvbSB0aGUgc21wX21iKCkgb3Bl
cmF0aW9uLg0KDQpbU2hpIFh1ZWxpbi1CMjkyMzddIE9ubHkgYWRkIHNtcF9tYigpIGRvZXNuJ3Qg
d29yay4gSXQgb25seSBzeW5jIG9uIHRoaXMgc3RlcCwgYnV0IG5leHQgc3RlcCBpcyB0aGUgc2Ft
ZSBhcyBqdXN0IGdldHRpbmcgaW50byB0aGlzIGZ1bmN0aW9uIHdpdGhvdXQgc21wX21iIG9wZXJh
dGlvbi4NCg0KVGhhbmtzLA0KSXJhDQoNCj4gLS0tLS1PcmlnaW5hbCBNZXNzYWdlLS0tLS0NCj4g
RnJvbTogSXJhIFcuIFNueWRlciBbbWFpbHRvOml3c0BvdnJvLmNhbHRlY2guZWR1XQ0KPiBTZW50
OiAyMDEx5bm0MTHmnIgyM+aXpSAyOjU5DQo+IFRvOiBTaGkgWHVlbGluLUIyOTIzNw0KPiBDYzog
ZGFuLmoud2lsbGlhbXNAaW50ZWwuY29tOyBMaSBZYW5nLVI1ODQ3MjsgendAemgta2VybmVsLm9y
ZzsgDQo+IHZpbm9kLmtvdWxAaW50ZWwuY29tOyBsaW51eHBwYy1kZXZAbGlzdHMub3psYWJzLm9y
ZzsgDQo+IGxpbnV4LWtlcm5lbEB2Z2VyLmtlcm5lbC5vcmcNCj4gU3ViamVjdDogUmU6IFtQQVRD
SF1bUkZDXSBmc2xkbWE6IGZpeCBwZXJmb3JtYW5jZSBkZWdyYWRhdGlvbiBieSBvcHRpbWl6aW5n
IHNwaW5sb2NrIHVzZS4NCj4gDQo+IE9uIFR1ZSwgTm92IDIyLCAyMDExIGF0IDEyOjU1OjA1UE0g
KzA4MDAsIGIyOTIzN0BmcmVlc2NhbGUuY29tIHdyb3RlOg0KPiA+IEZyb206IEZvcnJlc3QgU2hp
IDxiMjkyMzdAZnJlZXNjYWxlLmNvbT4NCj4gPiANCj4gPiAgICAgZG1hIHN0YXR1cyBjaGVjayBm
dW5jdGlvbiBmc2xfdHhfc3RhdHVzIGlzIGhlYXZpbHkgY2FsbGVkIGluDQo+ID4gICAgIGEgdGln
aHQgbG9vcCBhbmQgdGhlIGRlc2MgbG9jayBpbiBmc2xfdHhfc3RhdHVzIGNvbnRlbmRlZCBieQ0K
PiA+ICAgICB0aGUgZG1hIHN0YXR1cyB1cGRhdGUgZnVuY3Rpb24uIHRoaXMgY2F1c2VkIHRoZSBk
bWEgcGVyZm9ybWFuY2UNCj4gPiAgICAgZGVncmFkZXMgbXVjaC4NCj4gPiANCj4gPiAgICAgdGhp
cyBwYXRjaCByZWxlYXNlcyB0aGUgbG9jayBpbiB0aGUgZnNsX3R4X3N0YXR1cyBmdW5jdGlvbi4N
Cj4gPiAgICAgSSBiZWxpZXZlIGl0IGhhcyBubyBuZWdsZWN0IGltcGFjdCBvbiB0aGUgZm9sbG93
aW5nIGNhbGwgb2YNCj4gPiAgICAgZG1hX2FzeW5jX2lzX2NvbXBsZXRlKC4uLikuDQo+ID4gDQo+
ID4gICAgIHdlIGNhbiBzZWUgYmVsb3cgdGhyZWUgY29uZGl0aW9ucyB3aWxsIGJlIGlkZW50aWZp
ZWQgYXMgc3VjY2Vzcw0KPiA+ICAgICBhKSAgeCA8IGNvbXBsZXRlIDwgdXNlDQo+ID4gICAgIGIp
ICB4IDwgY29tcGxldGUrTiA8IHVzZStODQo+ID4gICAgIGMpICB4IDwgY29tcGxldGUgPCB1c2Ur
Tg0KPiA+ICAgICBoZXJlIGNvbXBsZXRlIGlzIHRoZSBjb21wbGV0ZWRfY29va2llLCB1c2UgaXMg
dGhlIGxhc3RfdXNlZA0KPiA+ICAgICBjb29raWUsIHggaXMgdGhlIHF1ZXJ5aW5nIGNvb2tpZSwg
TiBpcyBNQVggY29va2llDQo+ID4gDQo+ID4gICAgIHdoZW4gY2hhbi0+Y29tcGxldGVkX2Nvb2tp
ZSBpcyBiZWluZyByZWFkLCB0aGUgbGFzdF91c2VkIG1heQ0KPiA+ICAgICBiZSBpbmNyZXNlZC4g
QW55d2F5IGl0IGhhcyBubyBuZWdsZWN0IGltcGFjdCBvbiB0aGUgZG1hIHN0YXR1cw0KPiA+ICAg
ICBkZWNpc2lvbi4NCj4gPiANCj4gPiAgICAgU2lnbmVkLW9mZi1ieTogRm9ycmVzdCBTaGkgPHh1
ZWxpbi5zaGlAZnJlZXNjYWxlLmNvbT4NCj4gPiAtLS0NCj4gPiAgZHJpdmVycy9kbWEvZnNsZG1h
LmMgfCAgICA1IC0tLS0tDQo+ID4gIDEgZmlsZXMgY2hhbmdlZCwgMCBpbnNlcnRpb25zKCspLCA1
IGRlbGV0aW9ucygtKQ0KPiA+IA0KPiA+IGRpZmYgLS1naXQgYS9kcml2ZXJzL2RtYS9mc2xkbWEu
YyBiL2RyaXZlcnMvZG1hL2ZzbGRtYS5jIGluZGV4IA0KPiA+IDhhNzgxNTQuLjFkY2E1NmYgMTAw
NjQ0DQo+ID4gLS0tIGEvZHJpdmVycy9kbWEvZnNsZG1hLmMNCj4gPiArKysgYi9kcml2ZXJzL2Rt
YS9mc2xkbWEuYw0KPiA+IEBAIC05ODYsMTUgKzk4NiwxMCBAQCBzdGF0aWMgZW51bSBkbWFfc3Rh
dHVzIGZzbF90eF9zdGF0dXMoc3RydWN0IGRtYV9jaGFuICpkY2hhbiwNCj4gPiAgCXN0cnVjdCBm
c2xkbWFfY2hhbiAqY2hhbiA9IHRvX2ZzbF9jaGFuKGRjaGFuKTsNCj4gPiAgCWRtYV9jb29raWVf
dCBsYXN0X2NvbXBsZXRlOw0KPiA+ICAJZG1hX2Nvb2tpZV90IGxhc3RfdXNlZDsNCj4gPiAtCXVu
c2lnbmVkIGxvbmcgZmxhZ3M7DQo+ID4gLQ0KPiA+IC0Jc3Bpbl9sb2NrX2lycXNhdmUoJmNoYW4t
PmRlc2NfbG9jaywgZmxhZ3MpOw0KPiA+ICANCj4gDQo+IFRoaXMgd2lsbCBjYXVzZSBhIGJ1Zy4g
U2VlIGJlbG93IGZvciBhIGRldGFpbGVkIGV4cGxhbmF0aW9uLiBZb3UgbmVlZCB0aGlzIGluc3Rl
YWQ6DQo+IA0KPiAJLyoNCj4gCSAqIE9uIGFuIFNNUCBzeXN0ZW0sIHdlIG11c3QgZW5zdXJlIHRo
YXQgdGhpcyBDUFUgaGFzIHNlZW4gdGhlDQo+IAkgKiBtZW1vcnkgYWNjZXNzZXMgcGVyZm9ybWVk
IGJ5IGFub3RoZXIgQ1BVIHVuZGVyIHRoZQ0KPiAJICogY2hhbi0+ZGVzY19sb2NrIHNwaW5sb2Nr
Lg0KPiAJICovDQo+IAlzbXBfbWIoKTsNCj4gPiAgCWxhc3RfY29tcGxldGUgPSBjaGFuLT5jb21w
bGV0ZWRfY29va2llOw0KPiA+ICAJbGFzdF91c2VkID0gZGNoYW4tPmNvb2tpZTsNCj4gPiAgDQo+
ID4gLQlzcGluX3VubG9ja19pcnFyZXN0b3JlKCZjaGFuLT5kZXNjX2xvY2ssIGZsYWdzKTsNCj4g
PiAtDQo+ID4gIAlkbWFfc2V0X3R4X3N0YXRlKHR4c3RhdGUsIGxhc3RfY29tcGxldGUsIGxhc3Rf
dXNlZCwgMCk7DQo+ID4gIAlyZXR1cm4gZG1hX2FzeW5jX2lzX2NvbXBsZXRlKGNvb2tpZSwgbGFz
dF9jb21wbGV0ZSwgbGFzdF91c2VkKTsgIH0NCj4gDQo+IEZhY3RzOg0KPiAtIGRjaGFuLT5jb29r
aWUgaXMgdGhlIHNhbWUgbWVtYmVyIGFzIGNoYW4tPmNvbW1vbi5jb29raWUgKHNhbWUgbWVtb3J5
IA0KPiBsb2NhdGlvbikNCj4gLSBjaGFuLT5jb21tb24uY29va2llIGlzIHRoZSAibGFzdCBhbGxv
Y2F0ZWQgY29va2llIGZvciBhIHBlbmRpbmcgdHJhbnNhY3Rpb24iDQo+IC0gY2hhbi0+Y29tcGxl
dGVkX2Nvb2tpZSBpcyB0aGUgImxhc3QgY29tcGxldGVkIHRyYW5zYWN0aW9uIg0KPiANCj4gSSBo
YXZlIHJlcGxhY2VkICJkY2hhbi0+Y29va2llIiB3aXRoICJjaGFuLT5jb21tb24uY29va2llIiBp
biB0aGUgYmVsb3cgZXhwbGFuYXRpb24sIHRvIGtlZXAgZXZlcnl0aGluZyByZWZlcmVuY2VkIGZy
b20gdGhlIHNhbWUgc3RydWN0dXJlLg0KPiANCj4gVmFyaWFibGUgdXNhZ2UgYmVmb3JlIHlvdXIg
Y2hhbmdlLiBFdmVyeXRoaW5nIGlzIHVzZWQgbG9ja2VkLg0KPiAtIFJXIGNoYW4tPmNvbW1vbi5j
b29raWUJCShmc2xfZG1hX3R4X3N1Ym1pdCkNCj4gLSBSICBjaGFuLT5jb21tb24uY29va2llCQko
ZnNsX3R4X3N0YXR1cykNCj4gLSBSICBjaGFuLT5jb21wbGV0ZWRfY29va2llCQkoZnNsX3R4X3N0
YXR1cykNCj4gLSBXICBjaGFuLT5jb21wbGV0ZWRfY29va2llCQkoZG1hX2RvX3Rhc2tsZXQpDQo+
IA0KPiBWYXJpYWJsZSB1c2FnZSBhZnRlciB5b3VyIGNoYW5nZToNCj4gLSBSVyBjaGFuLT5jb21t
b24uY29va2llCQlMT0NLRUQNCj4gLSBSICBjaGFuLT5jb21tb24uY29va2llCQlOTyBMT0NLDQo+
IC0gUiAgY2hhbi0+Y29tcGxldGVkX2Nvb2tpZQkJTk8gTE9DSw0KPiAtIFcgIGNoYW4tPmNvbXBs
ZXRlZF9jb29raWUgICAgICAgICAgICAgTE9DS0VEDQo+IA0KPiBXaGF0IGlmIHdlIGFzc3VtZSB0
aGF0IHlvdSBoYXZlIGEgMiBDUFUgc3lzdGVtIChzdWNoIGFzIGEgUDIwMjApLiBBZnRlciB5b3Vy
IGNoYW5nZXMsIG9uZSBwb3NzaWJsZSBzZXF1ZW5jZSBpczoNCj4gDQo+ID09PSBDUFUxIC0gYWxs
b2NhdGUgKyBzdWJtaXQgZGVzY3JpcHRvcjogZnNsX2RtYV90eF9zdWJtaXQoKSA9PT0gDQo+IHNw
aW5fbG9ja19pcnFzYXZlDQo+IGRlc2NyaXB0b3ItPmNvb2tpZSA9IDIwCQkoeCBpbiB5b3VyIGV4
YW1wbGUpDQo+IGNoYW4tPmNvbW1vbi5jb29raWUgPSAyMAkodXNlZCBpbiB5b3VyIGV4YW1wbGUp
DQo+IHNwaW5fdW5sb2NrX2lycXJlc3RvcmUNCj4gDQo+ID09PSBDUFUyIC0gaW1tZWRpYXRlbHkg
Y2FsbHMgZnNsX3R4X3N0YXR1cygpID09PQ0KPiBjaGFuLT5jb21tb24uY29va2llID09IDE5DQo+
IGNoYW4tPmNvbXBsZXRlZF9jb29raWUgPT0gMTkNCj4gZGVzY3JpcHRvci0+Y29va2llID09IDIw
DQo+IA0KPiBTaW5jZSB3ZSBkb24ndCBoYXZlIGxvY2tzIGFueW1vcmUsIENQVTIgbWF5IG5vdCBo
YXZlIHNlZW4gdGhlIHdyaXRlIHRvDQo+IGNoYW4tPmNvbW1vbi5jb29raWUgeWV0Lg0KPiANCj4g
QWxzbyBhc3N1bWUgdGhhdCB0aGUgRE1BIGhhcmR3YXJlIGhhcyBub3Qgc3RhcnRlZCBwcm9jZXNz
aW5nIHRoZSANCj4gdHJhbnNhY3Rpb24geWV0LiBUaGVyZWZvcmUgZG1hX2RvX3Rhc2tsZXQoKSBo
YXMgbm90IGJlZW4gY2FsbGVkLCBhbmQNCj4gY2hhbi0+Y29tcGxldGVkX2Nvb2tpZSBoYXMgbm90
IGJlZW4gdXBkYXRlZC4NCj4gDQo+IEluIHRoaXMgY2FzZSwgZG1hX2FzeW5jX2lzX2NvbXBsZXRl
KCkgKG9uIENQVTIpIHJldHVybnMgRE1BX1NVQ0NFU1MsIGV2ZW4gdGhvdWdoIHRoZSBETUEgb3Bl
cmF0aW9uIGhhcyBub3Qgc3VjY2VlZGVkLiBUaGUgRE1BIG9wZXJhdGlvbiBoYXMgbm90IGV2ZW4g
c3RhcnRlZCB5ZXQhDQo+IA0KPiBUaGUgc21wX21iKCkgZml4ZXMgdGhpcywgc2luY2UgaXQgZm9y
Y2VzIENQVTIgdG8gaGF2ZSBzZWVuIGFsbCBtZW1vcnkgb3BlcmF0aW9ucyB0aGF0IGhhcHBlbmVk
IGJlZm9yZSBDUFUxIHJlbGVhc2VkIHRoZSBzcGlubG9jay4gU3BpbmxvY2tzIGFyZSBpbXBsaWNp
dCBTTVAgbWVtb3J5IGJhcnJpZXJzLg0KPiANCj4gVGhlcmVmb3JlLCB0aGUgYWJvdmUgZXhhbXBs
ZSBiZWNvbWVzOg0KPiBzbXBfbWIoKTsNCj4gY2hhbi0+Y29tbW9uLmNvb2tpZSA9PSAyMA0KPiBj
aGFuLT5jb21wbGV0ZWRfY29va2llID09IDE5DQo+IGRlc2NyaXB0b3ItPmNvb2tpZSA9PSAyMA0K
PiANCj4gVGhlbiBkbWFfYXN5bmNfaXNfY29tcGxldGUoKSByZXR1cm5zIERNQV9JTl9QUk9HUkVT
Uywgd2hpY2ggaXMgY29ycmVjdC4NCj4gDQo+IFRoYW5rcywNCj4gSXJhDQo+IA0KPiANCj4gX19f
X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18NCj4gTGludXhwcGMt
ZGV2IG1haWxpbmcgbGlzdA0KPiBMaW51eHBwYy1kZXZAbGlzdHMub3psYWJzLm9yZw0KPiBodHRw
czovL2xpc3RzLm96bGFicy5vcmcvbGlzdGluZm8vbGludXhwcGMtZGV2DQoNCg==