From ab7f863e4183057dc494f3180199934a9637d401 Mon Sep 17 00:00:00 2001
From: Scott Rixner <rixner@rice.edu>
Date: Thu, 3 Mar 2011 09:30:08 +0000
Subject: xen: events: Process event channels notifications in round-robin
 order.

Avoids fairness issue resulting from domain 0 processing lowest
numbered event channel first.

Fixes bug #1115 "Event channel port scanning unfair".

Bugzilla: http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1115
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[ijc: forward ported from linux-2.6.18-xen.hg 324:7fe1c6d02a2b
 various variables have different names in this tree:
  l1  -> pending_words
  l2  -> pending_bits
  l1i -> word_idx
  l2i -> bit_idx]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 65 insertions(+), 7 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6befe6227159..75cc6f50bd29 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1027,6 +1027,11 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 
+/*
+ * Mask out the i least significant bits of w
+ */
+#define MASK_LSBS(w, i) (w & ((~0UL) << i))
+
 /*
  * Search the CPUs pending events bitmasks.  For each one found, map
  * the event number to an irq, and feed it into do_IRQ() for
@@ -1038,6 +1043,9 @@ static DEFINE_PER_CPU(unsigned, xed_nesting_count);
  */
 static void __xen_evtchn_do_upcall(void)
 {
+	static unsigned int last_word_idx = BITS_PER_LONG - 1;
+	static unsigned int last_bit_idx = BITS_PER_LONG - 1;
+	int word_idx, bit_idx;
 	int cpu = get_cpu();
 	struct shared_info *s = HYPERVISOR_shared_info;
 	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
@@ -1056,17 +1064,50 @@ static void __xen_evtchn_do_upcall(void)
 		wmb();
 #endif
 		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
+
+		word_idx = last_word_idx;
+		bit_idx = last_bit_idx;
+
 		while (pending_words != 0) {
 			unsigned long pending_bits;
-			int word_idx = __ffs(pending_words);
-			pending_words &= ~(1UL << word_idx);
+			unsigned long words;
+
+			word_idx = (word_idx + 1) % BITS_PER_LONG;
+			words = MASK_LSBS(pending_words, word_idx);
+
+			/*
+			 * If we masked out all events, wrap around to the
+			 * beginning.
+			 */
+			if (words == 0) {
+				word_idx = BITS_PER_LONG - 1;
+				bit_idx = BITS_PER_LONG - 1;
+				continue;
+			}
+			word_idx = __ffs(words);
 
-			while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
-				int bit_idx = __ffs(pending_bits);
-				int port = (word_idx * BITS_PER_LONG) + bit_idx;
-				int irq = evtchn_to_irq[port];
+			do {
+				unsigned long bits;
+				int port, irq;
 				struct irq_desc *desc;
 
+				pending_bits = active_evtchns(cpu, s, word_idx);
+
+				bit_idx = (bit_idx + 1) % BITS_PER_LONG;
+				bits = MASK_LSBS(pending_bits, bit_idx);
+
+				/* If we masked out all events, move on. */
+				if (bits == 0) {
+					bit_idx = BITS_PER_LONG - 1;
+					break;
+				}
+
+				bit_idx = __ffs(bits);
+
+				/* Process port. */
+				port = (word_idx * BITS_PER_LONG) + bit_idx;
+				irq = evtchn_to_irq[port];
+
 				mask_evtchn(port);
 				clear_evtchn(port);
 
@@ -1075,7 +1116,24 @@ static void __xen_evtchn_do_upcall(void)
 					if (desc)
 						generic_handle_irq_desc(irq, desc);
 				}
-			}
+
+				/*
+				 * If this is the final port processed, we'll
+				 * pick up here+1 next time.
+				 */
+				last_word_idx = word_idx;
+				last_bit_idx = bit_idx;
+
+			} while (bit_idx != BITS_PER_LONG - 1);
+
+			pending_bits = active_evtchns(cpu, s, word_idx);
+
+			/*
+			 * We handled all ports, so we can clear the
+			 * selector bit.
+			 */
+			if (pending_bits == 0)
+				pending_words &= ~(1UL << word_idx);
 		}
 
 		BUG_ON(!irqs_disabled());
-- 
cgit v1.2.3


From f1f4a323d46c90632a4d35d34f1d347ca7cb65f5 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 3 Mar 2011 09:29:36 +0000
Subject: xen: events: Make last processed event channel a per-cpu variable.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[ijc: forward ported from linux-2.6.18-xen.hg 325:b2768401db94]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 75cc6f50bd29..1fc3192468ef 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1026,6 +1026,8 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 }
 
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
+static DEFINE_PER_CPU(unsigned int, last_word_idx) = { BITS_PER_LONG - 1 };
+static DEFINE_PER_CPU(unsigned int, last_bit_idx) = { BITS_PER_LONG - 1 };
 
 /*
  * Mask out the i least significant bits of w
@@ -1043,8 +1045,6 @@ static DEFINE_PER_CPU(unsigned, xed_nesting_count);
  */
 static void __xen_evtchn_do_upcall(void)
 {
-	static unsigned int last_word_idx = BITS_PER_LONG - 1;
-	static unsigned int last_bit_idx = BITS_PER_LONG - 1;
 	int word_idx, bit_idx;
 	int cpu = get_cpu();
 	struct shared_info *s = HYPERVISOR_shared_info;
@@ -1065,8 +1065,8 @@ static void __xen_evtchn_do_upcall(void)
 #endif
 		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 
-		word_idx = last_word_idx;
-		bit_idx = last_bit_idx;
+		word_idx = __this_cpu_read(last_word_idx);
+		bit_idx = __this_cpu_read(last_bit_idx);
 
 		while (pending_words != 0) {
 			unsigned long pending_bits;
@@ -1121,9 +1121,8 @@ static void __xen_evtchn_do_upcall(void)
 				 * If this is the final port processed, we'll
 				 * pick up here+1 next time.
 				 */
-				last_word_idx = word_idx;
-				last_bit_idx = bit_idx;
-
+				__this_cpu_write(last_word_idx, word_idx);
+				__this_cpu_write(last_bit_idx, bit_idx);
 			} while (bit_idx != BITS_PER_LONG - 1);
 
 			pending_bits = active_evtchns(cpu, s, word_idx);
-- 
cgit v1.2.3


From ada6814c878c4d95fc8ca1402e49effbf3cc319a Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir.fraser@citrix.com>
Date: Thu, 3 Mar 2011 10:01:11 +0000
Subject: xen: events: Clean up round-robin evtchn scan.

Also fixes a couple of boundary cases.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[ijc: forward ported from linux-2.6.18-xen.hg 988:c88a02a22a05]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 1fc3192468ef..c49cb6d6b838 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1026,8 +1026,8 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 }
 
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
-static DEFINE_PER_CPU(unsigned int, last_word_idx) = { BITS_PER_LONG - 1 };
-static DEFINE_PER_CPU(unsigned int, last_bit_idx) = { BITS_PER_LONG - 1 };
+static DEFINE_PER_CPU(unsigned int, current_word_idx);
+static DEFINE_PER_CPU(unsigned int, current_bit_idx);
 
 /*
  * Mask out the i least significant bits of w
@@ -1065,23 +1065,21 @@ static void __xen_evtchn_do_upcall(void)
 #endif
 		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 
-		word_idx = __this_cpu_read(last_word_idx);
-		bit_idx = __this_cpu_read(last_bit_idx);
+		word_idx = __this_cpu_read(current_word_idx);
+		bit_idx = __this_cpu_read(current_bit_idx);
 
 		while (pending_words != 0) {
 			unsigned long pending_bits;
 			unsigned long words;
 
-			word_idx = (word_idx + 1) % BITS_PER_LONG;
 			words = MASK_LSBS(pending_words, word_idx);
 
 			/*
-			 * If we masked out all events, wrap around to the
-			 * beginning.
+			 * If we masked out all events, wrap to beginning.
 			 */
 			if (words == 0) {
-				word_idx = BITS_PER_LONG - 1;
-				bit_idx = BITS_PER_LONG - 1;
+				word_idx = 0;
+				bit_idx = 0;
 				continue;
 			}
 			word_idx = __ffs(words);
@@ -1093,14 +1091,11 @@ static void __xen_evtchn_do_upcall(void)
 
 				pending_bits = active_evtchns(cpu, s, word_idx);
 
-				bit_idx = (bit_idx + 1) % BITS_PER_LONG;
 				bits = MASK_LSBS(pending_bits, bit_idx);
 
 				/* If we masked out all events, move on. */
-				if (bits == 0) {
-					bit_idx = BITS_PER_LONG - 1;
+				if (bits == 0)
 					break;
-				}
 
 				bit_idx = __ffs(bits);
 
@@ -1117,22 +1112,23 @@ static void __xen_evtchn_do_upcall(void)
 						generic_handle_irq_desc(irq, desc);
 				}
 
-				/*
-				 * If this is the final port processed, we'll
-				 * pick up here+1 next time.
-				 */
-				__this_cpu_write(last_word_idx, word_idx);
-				__this_cpu_write(last_bit_idx, bit_idx);
-			} while (bit_idx != BITS_PER_LONG - 1);
+				bit_idx = (bit_idx + 1) % BITS_PER_LONG;
+
+				/* Next caller starts at last processed + 1 */
+				__this_cpu_write(current_word_idx,
+						 bit_idx ? word_idx :
+						 (word_idx+1) % BITS_PER_LONG);
+				__this_cpu_write(current_bit_idx, bit_idx);
+			} while (bit_idx != 0);
 
 			pending_bits = active_evtchns(cpu, s, word_idx);
 
-			/*
-			 * We handled all ports, so we can clear the
-			 * selector bit.
-			 */
+			/* If we handled all ports, clear the selector bit. */
 			if (pending_bits == 0)
 				pending_words &= ~(1UL << word_idx);
+
+			word_idx = (word_idx + 1) % BITS_PER_LONG;
+			bit_idx = 0;
 		}
 
 		BUG_ON(!irqs_disabled());
-- 
cgit v1.2.3


From 24b51c2f2de019a4596415e7bb1e92711127d0e0 Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir.fraser@citrix.com>
Date: Thu, 3 Mar 2011 11:06:28 +0000
Subject: xen: events: Make round-robin scan fairer by snapshotting each l2
 word once only

(except for starting l2 word, which we scan in two parts).

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[ijc: forward ported from linux-2.6.18-xen.hg 990:427276ac595d]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index c49cb6d6b838..0c3f17ba3956 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1045,7 +1045,9 @@ static DEFINE_PER_CPU(unsigned int, current_bit_idx);
  */
 static void __xen_evtchn_do_upcall(void)
 {
+	int start_word_idx, start_bit_idx;
 	int word_idx, bit_idx;
+	int i;
 	int cpu = get_cpu();
 	struct shared_info *s = HYPERVISOR_shared_info;
 	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
@@ -1065,10 +1067,12 @@ static void __xen_evtchn_do_upcall(void)
 #endif
 		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 
-		word_idx = __this_cpu_read(current_word_idx);
-		bit_idx = __this_cpu_read(current_bit_idx);
+		start_word_idx = __this_cpu_read(current_word_idx);
+		start_bit_idx = __this_cpu_read(current_bit_idx);
+
+		word_idx = start_word_idx;
 
-		while (pending_words != 0) {
+		for (i = 0; pending_words != 0; i++) {
 			unsigned long pending_bits;
 			unsigned long words;
 
@@ -1084,13 +1088,23 @@ static void __xen_evtchn_do_upcall(void)
 			}
 			word_idx = __ffs(words);
 
+			pending_bits = active_evtchns(cpu, s, word_idx);
+			bit_idx = 0; /* usually scan entire word from start */
+			if (word_idx == start_word_idx) {
+				/* We scan the starting word in two parts */
+				if (i == 0)
+					/* 1st time: start in the middle */
+					bit_idx = start_bit_idx;
+				else
+					/* 2nd time: mask bits done already */
+					bit_idx &= (1UL << start_bit_idx) - 1;
+			}
+
 			do {
 				unsigned long bits;
 				int port, irq;
 				struct irq_desc *desc;
 
-				pending_bits = active_evtchns(cpu, s, word_idx);
-
 				bits = MASK_LSBS(pending_bits, bit_idx);
 
 				/* If we masked out all events, move on. */
@@ -1121,10 +1135,8 @@ static void __xen_evtchn_do_upcall(void)
 				__this_cpu_write(current_bit_idx, bit_idx);
 			} while (bit_idx != 0);
 
-			pending_bits = active_evtchns(cpu, s, word_idx);
-
-			/* If we handled all ports, clear the selector bit. */
-			if (pending_bits == 0)
+			/* Scan start_l1i twice; all others once. */
+			if ((word_idx != start_word_idx) || (i != 0))
 				pending_words &= ~(1UL << word_idx);
 
 			word_idx = (word_idx + 1) % BITS_PER_LONG;
-- 
cgit v1.2.3


From 3b7bcdf2823a59438301a73af8d0d31439a8f3d9 Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir.fraser@citrix.com>
Date: Thu, 3 Mar 2011 10:13:26 +0000
Subject: xen: events: Remove redundant clear of l2i at end of round-robin loop

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[ijc: forward ported from linux-2.6.18-xen.hg 991:9ba6d9f3fbc0]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 1 -
 1 file changed, 1 deletion(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 0c3f17ba3956..8786e06c4180 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1140,7 +1140,6 @@ static void __xen_evtchn_do_upcall(void)
 				pending_words &= ~(1UL << word_idx);
 
 			word_idx = (word_idx + 1) % BITS_PER_LONG;
-			bit_idx = 0;
 		}
 
 		BUG_ON(!irqs_disabled());
-- 
cgit v1.2.3


From be49472f0460455e8e0d9e6593837e09cbcc9ad7 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:02 +0000
Subject: xen: events: separate two unrelated halves of if condition

Clarifies which bit the comment applies to.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6befe6227159..684b0950538a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1143,10 +1143,14 @@ static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 	struct evtchn_bind_vcpu bind_vcpu;
 	int evtchn = evtchn_from_irq(irq);
 
-	/* events delivered via platform PCI interrupts are always
-	 * routed to vcpu 0 */
-	if (!VALID_EVTCHN(evtchn) ||
-		(xen_hvm_domain() && !xen_have_vector_callback))
+	if (!VALID_EVTCHN(evtchn))
+		return -1;
+
+	/*
+	 * Events delivered via platform PCI interrupts are always
+	 * routed to vcpu 0 and hence cannot be rebound.
+	 */
+	if (xen_hvm_domain() && !xen_have_vector_callback)
 		return -1;
 
 	/* Send future instances of this interrupt to other vcpu. */
-- 
cgit v1.2.3


From 653378acdd477a299f468e396c7719911ac57881 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:04 +0000
Subject: xen: events: simplify comment

It is never valid assume any particular relationship between a Xen
PIRQ number and and Linux IRQ number so there is no need to hedge when
saying so.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 684b0950538a..0b27080b1918 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -583,13 +583,9 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
 	return xen_map_pirq_gsi(gsi, gsi, shareable, name);
 }
 
-/* xen_map_pirq_gsi might allocate irqs from the top down, as a
- * consequence don't assume that the irq number returned has a low value
- * or can be used as a pirq number unless you know otherwise.
- *
- * One notable exception is when xen_map_pirq_gsi is called passing an
- * hardware gsi as argument, in that case the irq number returned
- * matches the gsi number passed as second argument.
+/*
+ * Do not make any assumptions regarding the relationship between the
+ * IRQ number returned here and the Xen pirq argument.
  *
  * Note: We don't assign an event channel until the irq actually started
  * up.  Return an existing irq if we've already got one for the gsi.
-- 
cgit v1.2.3


From a0e181167ee4254988c8c89d26ffd8ef4cb7deb0 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:03 +0000
Subject: xen: events: fix xen_map_pirq_gsi error return

Fix initial value of irq so that first goto out (if pirq or gsi
arguments are too large) actually returns an error.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 0b27080b1918..a9c154d1d2ff 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -592,7 +592,7 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
  */
 int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
 {
-	int irq = 0;
+	int irq = -1;
 	struct physdev_irq irq_op;
 
 	spin_lock(&irq_mapping_update_lock);
-- 
cgit v1.2.3


From 76465b2dafb8ce471f115b6af80f7a67a1fda377 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:05 +0000
Subject: xen: events: remove unused public functions

I was unable to find any user of these functions in either the
functionality pending for 2.6.39 or the xen/next-2.6.32 branch of
xen.git

An exception to this was xen_gsi_from_irq which did appear to be used
in xen/next-2.6.32's pciback. However in the 2.6.39 version of pciback
xen_pirq_from_irq is, correctly AFAICT, used instead.

Only a minority of functions in events.h use "extern" so drop it from
those places for consistency.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 20 --------------------
 1 file changed, 20 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index a9c154d1d2ff..d52defda53b1 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -222,16 +222,6 @@ static unsigned gsi_from_irq(unsigned irq)
 	return info->u.pirq.gsi;
 }
 
-static unsigned vector_from_irq(unsigned irq)
-{
-	struct irq_info *info = info_for_irq(irq);
-
-	BUG_ON(info == NULL);
-	BUG_ON(info->type != IRQT_PIRQ);
-
-	return info->u.pirq.vector;
-}
-
 static enum xen_irq_type type_from_irq(unsigned irq)
 {
 	return info_for_irq(irq)->type;
@@ -716,16 +706,6 @@ out:
 	return rc;
 }
 
-int xen_vector_from_irq(unsigned irq)
-{
-	return vector_from_irq(irq);
-}
-
-int xen_gsi_from_irq(unsigned irq)
-{
-	return gsi_from_irq(irq);
-}
-
 int xen_irq_from_pirq(unsigned pirq)
 {
 	return pirq_to_irq[pirq];
-- 
cgit v1.2.3


From 0a85226ff291a59b2d6596b28bbc4fe368ee5266 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:06 +0000
Subject: xen: events: rename restore_cpu_pirqs -> restore_pirqs

There is nothing per-cpu about this function.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index d52defda53b1..e828456777e5 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1213,7 +1213,7 @@ static int retrigger_dynirq(struct irq_data *data)
 	return ret;
 }
 
-static void restore_cpu_pirqs(void)
+static void restore_pirqs(void)
 {
 	int pirq, rc, irq, gsi;
 	struct physdev_map_pirq map_irq;
@@ -1375,7 +1375,7 @@ void xen_irq_resume(void)
 		restore_cpu_ipis(cpu);
 	}
 
-	restore_cpu_pirqs();
+	restore_pirqs();
 }
 
 static struct irq_chip xen_dynamic_chip __read_mostly = {
-- 
cgit v1.2.3


From f4d0635bf8894b7ba43d7a54733f3e26fe6ced2e Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:07 +0000
Subject: xen: events: refactor GSI pirq bindings functions

Following the example set by xen_allocate_pirq_msi and
xen_bind_pirq_msi_to_irq:

xen_allocate_pirq becomes xen_allocate_pirq_gsi and now only allocates
a pirq number and does not bind it.

xen_map_pirq_gsi becomes xen_bind_pirq_gsi_to_irq and binds an
existing pirq.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e828456777e5..a40b2a1c6255 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -568,9 +568,9 @@ static int find_irq_by_gsi(unsigned gsi)
 	return -1;
 }
 
-int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
+int xen_allocate_pirq_gsi(unsigned gsi)
 {
-	return xen_map_pirq_gsi(gsi, gsi, shareable, name);
+	return gsi;
 }
 
 /*
@@ -580,7 +580,8 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
  * Note: We don't assign an event channel until the irq actually started
  * up.  Return an existing irq if we've already got one for the gsi.
  */
-int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
+int xen_bind_pirq_gsi_to_irq(unsigned gsi,
+			     unsigned pirq, int shareable, char *name)
 {
 	int irq = -1;
 	struct physdev_irq irq_op;
-- 
cgit v1.2.3


From cb60d11427bbdd42c27edfa2ef1fa6344f455e1d Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:08 +0000
Subject: xen: events: use per-cpu variable for cpu_evtchn_mask

I can't see any reason why it isn't already.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index a40b2a1c6255..2dffa43696d8 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -107,19 +107,9 @@ static struct irq_info *irq_info;
 static int *pirq_to_irq;
 
 static int *evtchn_to_irq;
-struct cpu_evtchn_s {
-	unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
-};
-
-static __initdata struct cpu_evtchn_s init_evtchn_mask = {
-	.bits[0 ... (NR_EVENT_CHANNELS/BITS_PER_LONG)-1] = ~0ul,
-};
-static struct cpu_evtchn_s *cpu_evtchn_mask_p = &init_evtchn_mask;
 
-static inline unsigned long *cpu_evtchn_mask(int cpu)
-{
-	return cpu_evtchn_mask_p[cpu].bits;
-}
+static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
+		      cpu_evtchn_mask);
 
 /* Xen will never allocate port zero for any purpose. */
 #define VALID_EVTCHN(chn)	((chn) != 0)
@@ -257,7 +247,7 @@ static inline unsigned long active_evtchns(unsigned int cpu,
 					   unsigned int idx)
 {
 	return (sh->evtchn_pending[idx] &
-		cpu_evtchn_mask(cpu)[idx] &
+		per_cpu(cpu_evtchn_mask, cpu)[idx] &
 		~sh->evtchn_mask[idx]);
 }
 
@@ -270,8 +260,8 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 	cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu));
 #endif
 
-	clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
-	set_bit(chn, cpu_evtchn_mask(cpu));
+	clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
+	set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
 
 	irq_info[irq].cpu = cpu;
 }
@@ -289,8 +279,8 @@ static void init_evtchn_cpu_bindings(void)
 #endif
 
 	for_each_possible_cpu(i)
-		memset(cpu_evtchn_mask(i),
-		       (i == 0) ? ~0 : 0, sizeof(struct cpu_evtchn_s));
+		memset(per_cpu(cpu_evtchn_mask, i),
+		       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
 
 }
 
@@ -925,7 +915,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 {
 	struct shared_info *sh = HYPERVISOR_shared_info;
 	int cpu = smp_processor_id();
-	unsigned long *cpu_evtchn = cpu_evtchn_mask(cpu);
+	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
 	int i;
 	unsigned long flags;
 	static DEFINE_SPINLOCK(debug_lock);
@@ -1462,8 +1452,6 @@ void __init xen_init_IRQ(void)
 {
 	int i;
 
-	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
-				    GFP_KERNEL);
 	irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
 
 	/* We are using nr_irqs as the maximum number of pirq available but
-- 
cgit v1.2.3


From 9158c3588a0693ef11208f5961f0d6b0241694d8 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:09 +0000
Subject: xen: events: turn irq_info constructors into initialiser functions

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 104 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 66 insertions(+), 38 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 2dffa43696d8..72725faa2e85 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -118,46 +118,76 @@ static struct irq_chip xen_dynamic_chip;
 static struct irq_chip xen_percpu_chip;
 static struct irq_chip xen_pirq_chip;
 
-/* Constructor for packed IRQ information. */
-static struct irq_info mk_unbound_info(void)
+/* Get info for IRQ */
+static struct irq_info *info_for_irq(unsigned irq)
 {
-	return (struct irq_info) { .type = IRQT_UNBOUND };
+	return &irq_info[irq];
 }
 
-static struct irq_info mk_evtchn_info(unsigned short evtchn)
+/* Constructors for packed IRQ information. */
+static void xen_irq_info_common_init(struct irq_info *info,
+				     enum xen_irq_type type,
+				     unsigned short evtchn,
+				     unsigned short cpu)
 {
-	return (struct irq_info) { .type = IRQT_EVTCHN, .evtchn = evtchn,
-			.cpu = 0 };
+
+	BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
+
+	info->type = type;
+	info->evtchn = evtchn;
+	info->cpu = cpu;
 }
 
-static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
+static void xen_irq_info_evtchn_init(unsigned irq,
+				     unsigned short evtchn)
 {
-	return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
-			.cpu = 0, .u.ipi = ipi };
+	struct irq_info *info = info_for_irq(irq);
+
+	xen_irq_info_common_init(info, IRQT_EVTCHN, evtchn, 0);
 }
 
-static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
+static void xen_irq_info_ipi_init(unsigned irq,
+				  unsigned short evtchn,
+				  enum ipi_vector ipi)
 {
-	return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
-			.cpu = 0, .u.virq = virq };
+	struct irq_info *info = info_for_irq(irq);
+
+	xen_irq_info_common_init(info, IRQT_IPI, evtchn, 0);
+
+	info->u.ipi = ipi;
 }
 
-static struct irq_info mk_pirq_info(unsigned short evtchn, unsigned short pirq,
-				    unsigned short gsi, unsigned short vector)
+static void xen_irq_info_virq_init(unsigned irq,
+				   unsigned short evtchn,
+				   unsigned short virq)
 {
-	return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
-			.cpu = 0,
-			.u.pirq = { .pirq = pirq, .gsi = gsi, .vector = vector } };
+	struct irq_info *info = info_for_irq(irq);
+
+	xen_irq_info_common_init(info, IRQT_VIRQ, evtchn, 0);
+
+	info->u.virq = virq;
 }
 
-/*
- * Accessors for packed IRQ information.
- */
-static struct irq_info *info_for_irq(unsigned irq)
+static void xen_irq_info_pirq_init(unsigned irq,
+				   unsigned short evtchn,
+				   unsigned short pirq,
+				   unsigned short gsi,
+				   unsigned short vector,
+				   unsigned char flags)
 {
-	return &irq_info[irq];
+	struct irq_info *info = info_for_irq(irq);
+
+	xen_irq_info_common_init(info, IRQT_PIRQ, evtchn, 0);
+
+	info->u.pirq.pirq = pirq;
+	info->u.pirq.gsi = gsi;
+	info->u.pirq.vector = vector;
+	info->u.pirq.flags = flags;
 }
 
+/*
+ * Accessors for packed IRQ information.
+ */
 static unsigned int evtchn_from_irq(unsigned irq)
 {
 	if (unlikely(WARN(irq < 0 || irq >= nr_irqs, "Invalid irq %d!\n", irq)))
@@ -414,6 +444,8 @@ static int xen_allocate_irq_gsi(unsigned gsi)
 
 static void xen_free_irq(unsigned irq)
 {
+	irq_info[irq].type = IRQT_UNBOUND;
+
 	/* Legacy IRQ descriptors are managed by the arch. */
 	if (irq < NR_IRQS_LEGACY)
 		return;
@@ -610,8 +642,8 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 		goto out;
 	}
 
-	irq_info[irq] = mk_pirq_info(0, pirq, gsi, irq_op.vector);
-	irq_info[irq].u.pirq.flags |= shareable ? PIRQ_SHAREABLE : 0;
+	xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector,
+			       shareable ? PIRQ_SHAREABLE : 0);
 	pirq_to_irq[pirq] = irq;
 
 out:
@@ -649,7 +681,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 	set_irq_chip_and_handler_name(irq, &xen_pirq_chip,
 				      handle_level_irq, name);
 
-	irq_info[irq] = mk_pirq_info(0, pirq, 0, vector);
+	xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, 0);
 	pirq_to_irq[pirq] = irq;
 	ret = set_irq_msi(irq, msidesc);
 	if (ret < 0)
@@ -688,8 +720,6 @@ int xen_destroy_irq(int irq)
 	}
 	pirq_to_irq[info->u.pirq.pirq] = -1;
 
-	irq_info[irq] = mk_unbound_info();
-
 	xen_free_irq(irq);
 
 out:
@@ -717,7 +747,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 					      handle_fasteoi_irq, "event");
 
 		evtchn_to_irq[evtchn] = irq;
-		irq_info[irq] = mk_evtchn_info(evtchn);
+		xen_irq_info_evtchn_init(irq, evtchn);
 	}
 
 	spin_unlock(&irq_mapping_update_lock);
@@ -750,7 +780,7 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 		evtchn = bind_ipi.port;
 
 		evtchn_to_irq[evtchn] = irq;
-		irq_info[irq] = mk_ipi_info(evtchn, ipi);
+		xen_irq_info_ipi_init(irq, evtchn, ipi);
 		per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 
 		bind_evtchn_to_cpu(evtchn, cpu);
@@ -785,7 +815,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 		evtchn = bind_virq.port;
 
 		evtchn_to_irq[evtchn] = irq;
-		irq_info[irq] = mk_virq_info(evtchn, virq);
+		xen_irq_info_virq_init(irq, evtchn, virq);
 
 		per_cpu(virq_to_irq, cpu)[virq] = irq;
 
@@ -828,11 +858,9 @@ static void unbind_from_irq(unsigned int irq)
 		evtchn_to_irq[evtchn] = -1;
 	}
 
-	if (irq_info[irq].type != IRQT_UNBOUND) {
-		irq_info[irq] = mk_unbound_info();
+	BUG_ON(irq_info[irq].type == IRQT_UNBOUND);
 
-		xen_free_irq(irq);
-	}
+	xen_free_irq(irq);
 
 	spin_unlock(&irq_mapping_update_lock);
 }
@@ -1093,7 +1121,7 @@ void rebind_evtchn_irq(int evtchn, int irq)
 	BUG_ON(info->type == IRQT_UNBOUND);
 
 	evtchn_to_irq[evtchn] = irq;
-	irq_info[irq] = mk_evtchn_info(evtchn);
+	xen_irq_info_evtchn_init(irq, evtchn);
 
 	spin_unlock(&irq_mapping_update_lock);
 
@@ -1229,7 +1257,7 @@ static void restore_pirqs(void)
 		if (rc) {
 			printk(KERN_WARNING "xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
 					gsi, irq, pirq, rc);
-			irq_info[irq] = mk_unbound_info();
+			xen_free_irq(irq);
 			pirq_to_irq[pirq] = -1;
 			continue;
 		}
@@ -1261,7 +1289,7 @@ static void restore_cpu_virqs(unsigned int cpu)
 
 		/* Record the new mapping. */
 		evtchn_to_irq[evtchn] = irq;
-		irq_info[irq] = mk_virq_info(evtchn, virq);
+		xen_irq_info_virq_init(irq, evtchn, virq);
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 }
@@ -1286,7 +1314,7 @@ static void restore_cpu_ipis(unsigned int cpu)
 
 		/* Record the new mapping. */
 		evtchn_to_irq[evtchn] = irq;
-		irq_info[irq] = mk_ipi_info(evtchn, ipi);
+		xen_irq_info_ipi_init(irq, evtchn, ipi);
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 }
-- 
cgit v1.2.3


From 3d4cfa3736f2f080d3bde4f4329b7b6a7544e093 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:10 +0000
Subject: xen: events: push setup of irq<->{evtchn,ipi,virq,pirq} maps into
 irq_info init functions

Encapsulate setup of XXX_to_irq array in the relevant
xen_irq_info_*_init function.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 72725faa2e85..cf372d41077d 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -126,6 +126,7 @@ static struct irq_info *info_for_irq(unsigned irq)
 
 /* Constructors for packed IRQ information. */
 static void xen_irq_info_common_init(struct irq_info *info,
+				     unsigned irq,
 				     enum xen_irq_type type,
 				     unsigned short evtchn,
 				     unsigned short cpu)
@@ -136,6 +137,8 @@ static void xen_irq_info_common_init(struct irq_info *info,
 	info->type = type;
 	info->evtchn = evtchn;
 	info->cpu = cpu;
+
+	evtchn_to_irq[evtchn] = irq;
 }
 
 static void xen_irq_info_evtchn_init(unsigned irq,
@@ -143,29 +146,35 @@ static void xen_irq_info_evtchn_init(unsigned irq,
 {
 	struct irq_info *info = info_for_irq(irq);
 
-	xen_irq_info_common_init(info, IRQT_EVTCHN, evtchn, 0);
+	xen_irq_info_common_init(info, irq, IRQT_EVTCHN, evtchn, 0);
 }
 
-static void xen_irq_info_ipi_init(unsigned irq,
+static void xen_irq_info_ipi_init(unsigned cpu,
+				  unsigned irq,
 				  unsigned short evtchn,
 				  enum ipi_vector ipi)
 {
 	struct irq_info *info = info_for_irq(irq);
 
-	xen_irq_info_common_init(info, IRQT_IPI, evtchn, 0);
+	xen_irq_info_common_init(info, irq, IRQT_IPI, evtchn, 0);
 
 	info->u.ipi = ipi;
+
+	per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 }
 
-static void xen_irq_info_virq_init(unsigned irq,
+static void xen_irq_info_virq_init(unsigned cpu,
+				   unsigned irq,
 				   unsigned short evtchn,
 				   unsigned short virq)
 {
 	struct irq_info *info = info_for_irq(irq);
 
-	xen_irq_info_common_init(info, IRQT_VIRQ, evtchn, 0);
+	xen_irq_info_common_init(info, irq, IRQT_VIRQ, evtchn, 0);
 
 	info->u.virq = virq;
+
+	per_cpu(virq_to_irq, cpu)[virq] = irq;
 }
 
 static void xen_irq_info_pirq_init(unsigned irq,
@@ -177,12 +186,14 @@ static void xen_irq_info_pirq_init(unsigned irq,
 {
 	struct irq_info *info = info_for_irq(irq);
 
-	xen_irq_info_common_init(info, IRQT_PIRQ, evtchn, 0);
+	xen_irq_info_common_init(info, irq, IRQT_PIRQ, evtchn, 0);
 
 	info->u.pirq.pirq = pirq;
 	info->u.pirq.gsi = gsi;
 	info->u.pirq.vector = vector;
 	info->u.pirq.flags = flags;
+
+	pirq_to_irq[pirq] = irq;
 }
 
 /*
@@ -644,7 +655,6 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 
 	xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector,
 			       shareable ? PIRQ_SHAREABLE : 0);
-	pirq_to_irq[pirq] = irq;
 
 out:
 	spin_unlock(&irq_mapping_update_lock);
@@ -682,7 +692,6 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 				      handle_level_irq, name);
 
 	xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, 0);
-	pirq_to_irq[pirq] = irq;
 	ret = set_irq_msi(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -746,7 +755,6 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 					      handle_fasteoi_irq, "event");
 
-		evtchn_to_irq[evtchn] = irq;
 		xen_irq_info_evtchn_init(irq, evtchn);
 	}
 
@@ -779,9 +787,7 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 			BUG();
 		evtchn = bind_ipi.port;
 
-		evtchn_to_irq[evtchn] = irq;
-		xen_irq_info_ipi_init(irq, evtchn, ipi);
-		per_cpu(ipi_to_irq, cpu)[ipi] = irq;
+		xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
 
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
@@ -814,10 +820,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 			BUG();
 		evtchn = bind_virq.port;
 
-		evtchn_to_irq[evtchn] = irq;
-		xen_irq_info_virq_init(irq, evtchn, virq);
-
-		per_cpu(virq_to_irq, cpu)[virq] = irq;
+		xen_irq_info_virq_init(cpu, irq, evtchn, virq);
 
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
@@ -1120,7 +1123,6 @@ void rebind_evtchn_irq(int evtchn, int irq)
 	   so there should be a proper type */
 	BUG_ON(info->type == IRQT_UNBOUND);
 
-	evtchn_to_irq[evtchn] = irq;
 	xen_irq_info_evtchn_init(irq, evtchn);
 
 	spin_unlock(&irq_mapping_update_lock);
@@ -1288,8 +1290,7 @@ static void restore_cpu_virqs(unsigned int cpu)
 		evtchn = bind_virq.port;
 
 		/* Record the new mapping. */
-		evtchn_to_irq[evtchn] = irq;
-		xen_irq_info_virq_init(irq, evtchn, virq);
+		xen_irq_info_virq_init(cpu, irq, evtchn, virq);
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 }
@@ -1313,8 +1314,7 @@ static void restore_cpu_ipis(unsigned int cpu)
 		evtchn = bind_ipi.port;
 
 		/* Record the new mapping. */
-		evtchn_to_irq[evtchn] = irq;
-		xen_irq_info_ipi_init(irq, evtchn, ipi);
+		xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 }
-- 
cgit v1.2.3


From 6cb6537d34a146c8f3e232da9ffd79ae1265fed3 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:11 +0000
Subject: xen: events: maintain a list of Xen interrupts

In a PVHVM kernel not all interrupts are Xen interrupts (APIC interrupts can also be present).

Currently we get away with walking over all interrupts because the
lookup in the irq_info array simply returns IRQT_UNBOUND and we ignore
it. However this array will be going away in a future patch so we need
to manually track which interrupts have been allocated by the Xen
events infrastructure.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 59 +++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 44 insertions(+), 15 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index cf372d41077d..e119989ec15b 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -56,6 +56,8 @@
  */
 static DEFINE_SPINLOCK(irq_mapping_update_lock);
 
+static LIST_HEAD(xen_irq_list_head);
+
 /* IRQ <-> VIRQ mapping. */
 static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
 
@@ -85,7 +87,9 @@ enum xen_irq_type {
  */
 struct irq_info
 {
+	struct list_head list;
 	enum xen_irq_type type;	/* type */
+	unsigned irq;
 	unsigned short evtchn;	/* event channel */
 	unsigned short cpu;	/* cpu bound */
 
@@ -135,6 +139,7 @@ static void xen_irq_info_common_init(struct irq_info *info,
 	BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
 
 	info->type = type;
+	info->irq = irq;
 	info->evtchn = evtchn;
 	info->cpu = cpu;
 
@@ -311,10 +316,11 @@ static void init_evtchn_cpu_bindings(void)
 {
 	int i;
 #ifdef CONFIG_SMP
-	struct irq_desc *desc;
+	struct irq_info *info;
 
 	/* By default all event channels notify CPU#0. */
-	for_each_irq_desc(i, desc) {
+	list_for_each_entry(info, &xen_irq_list_head, list) {
+		struct irq_desc *desc = irq_to_desc(info->irq);
 		cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
 	}
 #endif
@@ -397,6 +403,21 @@ static void unmask_evtchn(int port)
 	put_cpu();
 }
 
+static void xen_irq_init(unsigned irq)
+{
+	struct irq_info *info;
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	/* By default all event channels notify CPU#0. */
+	cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
+
+	info = &irq_info[irq];
+
+	info->type = IRQT_UNBOUND;
+
+	list_add_tail(&info->list, &xen_irq_list_head);
+}
+
 static int xen_allocate_irq_dynamic(void)
 {
 	int first = 0;
@@ -426,6 +447,8 @@ retry:
 	if (irq < 0)
 		panic("No available IRQ to bind to: increase nr_irqs!\n");
 
+	xen_irq_init(irq);
+
 	return irq;
 }
 
@@ -444,18 +467,25 @@ static int xen_allocate_irq_gsi(unsigned gsi)
 
 	/* Legacy IRQ descriptors are already allocated by the arch. */
 	if (gsi < NR_IRQS_LEGACY)
-		return gsi;
+		irq = gsi;
+	else
+		irq = irq_alloc_desc_at(gsi, -1);
 
-	irq = irq_alloc_desc_at(gsi, -1);
 	if (irq < 0)
 		panic("Unable to allocate to IRQ%d (%d)\n", gsi, irq);
 
+	xen_irq_init(irq);
+
 	return irq;
 }
 
 static void xen_free_irq(unsigned irq)
 {
-	irq_info[irq].type = IRQT_UNBOUND;
+	struct irq_info *info = &irq_info[irq];
+
+	info->type = IRQT_UNBOUND;
+
+	list_del(&info->list);
 
 	/* Legacy IRQ descriptors are managed by the arch. */
 	if (irq < NR_IRQS_LEGACY)
@@ -586,16 +616,14 @@ static void ack_pirq(struct irq_data *data)
 
 static int find_irq_by_gsi(unsigned gsi)
 {
-	int irq;
-
-	for (irq = 0; irq < nr_irqs; irq++) {
-		struct irq_info *info = info_for_irq(irq);
+	struct irq_info *info;
 
-		if (info == NULL || info->type != IRQT_PIRQ)
+	list_for_each_entry(info, &xen_irq_list_head, list) {
+		if (info->type != IRQT_PIRQ)
 			continue;
 
-		if (gsi_from_irq(irq) == gsi)
-			return irq;
+		if (info->u.pirq.gsi == gsi)
+			return info->irq;
 	}
 
 	return -1;
@@ -1374,7 +1402,8 @@ void xen_poll_irq(int irq)
 
 void xen_irq_resume(void)
 {
-	unsigned int cpu, irq, evtchn;
+	unsigned int cpu, evtchn;
+	struct irq_info *info;
 
 	init_evtchn_cpu_bindings();
 
@@ -1383,8 +1412,8 @@ void xen_irq_resume(void)
 		mask_evtchn(evtchn);
 
 	/* No IRQ <-> event-channel mappings. */
-	for (irq = 0; irq < nr_irqs; irq++)
-		irq_info[irq].evtchn = 0; /* zap event-channel binding */
+	list_for_each_entry(info, &xen_irq_list_head, list)
+		info->evtchn = 0; /* zap event-channel binding */
 
 	for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 		evtchn_to_irq[evtchn] = -1;
-- 
cgit v1.2.3


From ca62ce8cde36cde5a31af8f9bb23e6430700e437 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:12 +0000
Subject: xen: events: dynamically allocate irq info structures

Removes nr_irq sized array allocation at start of day.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e119989ec15b..002283e01749 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -107,7 +107,6 @@ struct irq_info
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
 
-static struct irq_info *irq_info;
 static int *pirq_to_irq;
 
 static int *evtchn_to_irq;
@@ -125,7 +124,7 @@ static struct irq_chip xen_pirq_chip;
 /* Get info for IRQ */
 static struct irq_info *info_for_irq(unsigned irq)
 {
-	return &irq_info[irq];
+	return get_irq_data(irq);
 }
 
 /* Constructors for packed IRQ information. */
@@ -309,7 +308,7 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 	clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
 	set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
 
-	irq_info[irq].cpu = cpu;
+	info_for_irq(irq)->cpu = cpu;
 }
 
 static void init_evtchn_cpu_bindings(void)
@@ -328,7 +327,6 @@ static void init_evtchn_cpu_bindings(void)
 	for_each_possible_cpu(i)
 		memset(per_cpu(cpu_evtchn_mask, i),
 		       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
-
 }
 
 static inline void clear_evtchn(int port)
@@ -411,10 +409,14 @@ static void xen_irq_init(unsigned irq)
 	/* By default all event channels notify CPU#0. */
 	cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
 
-	info = &irq_info[irq];
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (info == NULL)
+		panic("Unable to allocate metadata for IRQ%d\n", irq);
 
 	info->type = IRQT_UNBOUND;
 
+	set_irq_data(irq, info);
+
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
@@ -481,12 +483,14 @@ static int xen_allocate_irq_gsi(unsigned gsi)
 
 static void xen_free_irq(unsigned irq)
 {
-	struct irq_info *info = &irq_info[irq];
-
-	info->type = IRQT_UNBOUND;
+	struct irq_info *info = get_irq_data(irq);
 
 	list_del(&info->list);
 
+	set_irq_data(irq, NULL);
+
+	kfree(info);
+
 	/* Legacy IRQ descriptors are managed by the arch. */
 	if (irq < NR_IRQS_LEGACY)
 		return;
@@ -649,10 +653,9 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 
 	spin_lock(&irq_mapping_update_lock);
 
-	if ((pirq > nr_irqs) || (gsi > nr_irqs)) {
-		printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
-			pirq > nr_irqs ? "pirq" :"",
-			gsi > nr_irqs ? "gsi" : "");
+	if (pirq > nr_irqs) {
+		printk(KERN_WARNING "xen_map_pirq_gsi: pirq %d > nr_irqs %d!\n",
+		       pirq, nr_irqs);
 		goto out;
 	}
 
@@ -889,7 +892,7 @@ static void unbind_from_irq(unsigned int irq)
 		evtchn_to_irq[evtchn] = -1;
 	}
 
-	BUG_ON(irq_info[irq].type == IRQT_UNBOUND);
+	BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
 
 	xen_free_irq(irq);
 
@@ -1509,8 +1512,6 @@ void __init xen_init_IRQ(void)
 {
 	int i;
 
-	irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
-
 	/* We are using nr_irqs as the maximum number of pirq available but
 	 * that number is actually chosen by Xen and we don't know exactly
 	 * what it is. Be careful choosing high pirq numbers. */
-- 
cgit v1.2.3


From 69c358ce377e998e3ababb494c2f8769dfb1715d Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:13 +0000
Subject: xen: events: remove use of nr_irqs as upper bound on number of pirqs

There isn't really much relationship between the two, other than
nr_irqs often being the larger of the two.

Allows us to remove a nr_irqs sized array, the only users of this
array are MSI setup and restore, neither of which are particularly
performance critical.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 59 ++++++++++++++++++++++------------------------------
 1 file changed, 25 insertions(+), 34 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 002283e01749..6782251e4029 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -107,8 +107,6 @@ struct irq_info
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
 
-static int *pirq_to_irq;
-
 static int *evtchn_to_irq;
 
 static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
@@ -196,8 +194,6 @@ static void xen_irq_info_pirq_init(unsigned irq,
 	info->u.pirq.gsi = gsi;
 	info->u.pirq.vector = vector;
 	info->u.pirq.flags = flags;
-
-	pirq_to_irq[pirq] = irq;
 }
 
 /*
@@ -247,16 +243,6 @@ static unsigned pirq_from_irq(unsigned irq)
 	return info->u.pirq.pirq;
 }
 
-static unsigned gsi_from_irq(unsigned irq)
-{
-	struct irq_info *info = info_for_irq(irq);
-
-	BUG_ON(info == NULL);
-	BUG_ON(info->type != IRQT_PIRQ);
-
-	return info->u.pirq.gsi;
-}
-
 static enum xen_irq_type type_from_irq(unsigned irq)
 {
 	return info_for_irq(irq)->type;
@@ -653,12 +639,6 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 
 	spin_lock(&irq_mapping_update_lock);
 
-	if (pirq > nr_irqs) {
-		printk(KERN_WARNING "xen_map_pirq_gsi: pirq %d > nr_irqs %d!\n",
-		       pirq, nr_irqs);
-		goto out;
-	}
-
 	irq = find_irq_by_gsi(gsi);
 	if (irq != -1) {
 		printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
@@ -758,7 +738,6 @@ int xen_destroy_irq(int irq)
 			goto out;
 		}
 	}
-	pirq_to_irq[info->u.pirq.pirq] = -1;
 
 	xen_free_irq(irq);
 
@@ -769,7 +748,24 @@ out:
 
 int xen_irq_from_pirq(unsigned pirq)
 {
-	return pirq_to_irq[pirq];
+	int irq;
+
+	struct irq_info *info;
+
+	spin_lock(&irq_mapping_update_lock);
+
+	list_for_each_entry(info, &xen_irq_list_head, list) {
+		if (info == NULL || info->type != IRQT_PIRQ)
+			continue;
+		irq = info->irq;
+		if (info->u.pirq.pirq == pirq)
+			goto out;
+	}
+	irq = -1;
+out:
+	spin_lock(&irq_mapping_update_lock);
+
+	return irq;
 }
 
 int bind_evtchn_to_irq(unsigned int evtchn)
@@ -1269,15 +1265,18 @@ static void restore_pirqs(void)
 {
 	int pirq, rc, irq, gsi;
 	struct physdev_map_pirq map_irq;
+	struct irq_info *info;
 
-	for (pirq = 0; pirq < nr_irqs; pirq++) {
-		irq = pirq_to_irq[pirq];
-		if (irq == -1)
+	list_for_each_entry(info, &xen_irq_list_head, list) {
+		if (info->type != IRQT_PIRQ)
 			continue;
 
+		pirq = info->u.pirq.pirq;
+		gsi = info->u.pirq.gsi;
+		irq = info->irq;
+
 		/* save/restore of PT devices doesn't work, so at this point the
 		 * only devices present are GSI based emulated devices */
-		gsi = gsi_from_irq(irq);
 		if (!gsi)
 			continue;
 
@@ -1291,7 +1290,6 @@ static void restore_pirqs(void)
 			printk(KERN_WARNING "xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
 					gsi, irq, pirq, rc);
 			xen_free_irq(irq);
-			pirq_to_irq[pirq] = -1;
 			continue;
 		}
 
@@ -1512,13 +1510,6 @@ void __init xen_init_IRQ(void)
 {
 	int i;
 
-	/* We are using nr_irqs as the maximum number of pirq available but
-	 * that number is actually chosen by Xen and we don't know exactly
-	 * what it is. Be careful choosing high pirq numbers. */
-	pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
-	for (i = 0; i < nr_irqs; i++)
-		pirq_to_irq[i] = -1;
-
 	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
 	for (i = 0; i < NR_EVENT_CHANNELS; i++)
-- 
cgit v1.2.3


From 6cb9bf3aaffcdd175574a9d66af4ad69156d0070 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:14 +0000
Subject: xen: events: do not workaround too-small nr_irqs

With the introduction of e7bcecb7b1d2 "genirq: Make nr_irqs runtime expandable"
nr_irqs can grow as necessary to accommodate our allocation requests.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 7 -------
 1 file changed, 7 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6782251e4029..7c3668960c75 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -423,15 +423,8 @@ static int xen_allocate_irq_dynamic(void)
 		first = get_nr_irqs_gsi();
 #endif
 
-retry:
 	irq = irq_alloc_desc_from(first, -1);
 
-	if (irq == -ENOMEM && first > NR_IRQS_LEGACY) {
-		printk(KERN_ERR "Out of dynamic IRQ space and eating into GSI space. You should increase nr_irqs\n");
-		first = max(NR_IRQS_LEGACY, first - NR_IRQS_LEGACY);
-		goto retry;
-	}
-
 	if (irq < 0)
 		panic("No available IRQ to bind to: increase nr_irqs!\n");
 
-- 
cgit v1.2.3


From 7bee976822a78bbb278790c2cd64293568592cdb Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 10 Mar 2011 16:08:15 +0000
Subject: xen: events: propagate irq allocation failure instead of panicking

Running out of IRQs need not be fatal to the machine as a whole.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 7c3668960c75..3566c00e1e3d 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -406,7 +406,7 @@ static void xen_irq_init(unsigned irq)
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
-static int xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irq_dynamic(void)
 {
 	int first = 0;
 	int irq;
@@ -425,15 +425,12 @@ static int xen_allocate_irq_dynamic(void)
 
 	irq = irq_alloc_desc_from(first, -1);
 
-	if (irq < 0)
-		panic("No available IRQ to bind to: increase nr_irqs!\n");
-
 	xen_irq_init(irq);
 
 	return irq;
 }
 
-static int xen_allocate_irq_gsi(unsigned gsi)
+static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 {
 	int irq;
 
@@ -452,9 +449,6 @@ static int xen_allocate_irq_gsi(unsigned gsi)
 	else
 		irq = irq_alloc_desc_at(gsi, -1);
 
-	if (irq < 0)
-		panic("Unable to allocate to IRQ%d (%d)\n", gsi, irq);
-
 	xen_irq_init(irq);
 
 	return irq;
@@ -640,6 +634,8 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 	}
 
 	irq = xen_allocate_irq_gsi(gsi);
+	if (irq < 0)
+		goto out;
 
 	set_irq_chip_and_handler_name(irq, &xen_pirq_chip,
 				      handle_level_irq, name);
@@ -771,6 +767,8 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 
 	if (irq == -1) {
 		irq = xen_allocate_irq_dynamic();
+		if (irq == -1)
+			goto out;
 
 		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 					      handle_fasteoi_irq, "event");
@@ -778,6 +776,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 		xen_irq_info_evtchn_init(irq, evtchn);
 	}
 
+out:
 	spin_unlock(&irq_mapping_update_lock);
 
 	return irq;
@@ -829,6 +828,8 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 
 	if (irq == -1) {
 		irq = xen_allocate_irq_dynamic();
+		if (irq == -1)
+			goto out;
 
 		set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 					      handle_percpu_irq, "virq");
@@ -845,6 +846,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 
+out:
 	spin_unlock(&irq_mapping_update_lock);
 
 	return irq;
@@ -897,6 +899,8 @@ int bind_evtchn_to_irqhandler(unsigned int evtchn,
 	int retval;
 
 	irq = bind_evtchn_to_irq(evtchn);
+	if (irq < 0)
+		return irq;
 	retval = request_irq(irq, handler, irqflags, devname, dev_id);
 	if (retval != 0) {
 		unbind_from_irq(irq);
@@ -915,6 +919,8 @@ int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 	int retval;
 
 	irq = bind_virq_to_irq(virq, cpu);
+	if (irq < 0)
+		return irq;
 	retval = request_irq(irq, handler, irqflags, devname, dev_id);
 	if (retval != 0) {
 		unbind_from_irq(irq);
-- 
cgit v1.2.3


From a7b807ce8c86925eef92fe6aa79cea4ac7f097c4 Mon Sep 17 00:00:00 2001
From: Ian Campbell <Ian.Campbell@citrix.com>
Date: Mon, 14 Mar 2011 09:50:39 +0000
Subject: xen: events: correct locking in xen_irq_from_pirq

One of those spin_lock() calls should be an unlock...

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 3566c00e1e3d..dc8177950d05 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -752,7 +752,7 @@ int xen_irq_from_pirq(unsigned pirq)
 	}
 	irq = -1;
 out:
-	spin_lock(&irq_mapping_update_lock);
+	spin_unlock(&irq_mapping_update_lock);
 
 	return irq;
 }
-- 
cgit v1.2.3


From 44626e4a3bd764283193e14e64f9324e48b4bfd8 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Tue, 15 Mar 2011 16:40:33 -0400
Subject: xen: events: Fix compile error if CONFIG_SMP is not defined.

drivers/xen/events.c:396: error: 'struct irq_data' has no member named 'affinity'

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'drivers/xen')

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index dc8177950d05..4591853f6ebc 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -392,8 +392,10 @@ static void xen_irq_init(unsigned irq)
 	struct irq_info *info;
 	struct irq_desc *desc = irq_to_desc(irq);
 
+#ifdef CONFIG_SMP
 	/* By default all event channels notify CPU#0. */
 	cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
+#endif
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (info == NULL)
-- 
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