From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
v3.18.138-rt116-rc1 stable review patch.
If anyone has any objections, please let me know.
-----------
[ Upstream commit 5c1b4cd70e2ca0c81038b65babe6dc66086322e0 ]
The locallock protects the per-CPU variable tce_page. The function
attempts to allocate memory while tce_page is protected (by disabling
interrupts).
Use local_irq_save() instead of local_irq_disable().
Cc: stable-rt@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Conflicts:
arch/powerpc/platforms/pseries/iommu.c
---
arch/powerpc/platforms/pseries/iommu.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 05a2c9eefc08..acc6f64f0cb8 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -36,6 +36,7 @@
#include <linux/crash_dump.h>
#include <linux/memory.h>
#include <linux/of.h>
+#include <linux/locallock.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/rtas.h>
@@ -177,6 +178,7 @@ static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
}
static DEFINE_PER_CPU(__be64 *, tce_page);
+static DEFINE_LOCAL_IRQ_LOCK(tcp_page_lock);
static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
long npages, unsigned long uaddr,
@@ -197,7 +199,8 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
direction, attrs);
}
- local_irq_save(flags); /* to protect tcep and the page behind it */
+ /* to protect tcep and the page behind it */
+ local_lock_irqsave(tcp_page_lock, flags);
tcep = __get_cpu_var(tce_page);
@@ -208,7 +211,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
/* If allocation fails, fall back to the loop implementation */
if (!tcep) {
- local_irq_restore(flags);
+ local_unlock_irqrestore(tcp_page_lock, flags);
return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
direction, attrs);
}
@@ -242,7 +245,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
tcenum += limit;
} while (npages > 0 && !rc);
- local_irq_restore(flags);
+ local_unlock_irqrestore(tcp_page_lock, flags);
if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
ret = (int)rc;
@@ -397,13 +400,14 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
u64 rc = 0;
long l, limit;
- local_irq_disable(); /* to protect tcep and the page behind it */
+ /* to protect tcep and the page behind it */
+ local_lock_irq(tcp_page_lock);
tcep = __get_cpu_var(tce_page);
if (!tcep) {
tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
if (!tcep) {
- local_irq_enable();
+ local_unlock_irq(tcp_page_lock);
return -ENOMEM;
}
__get_cpu_var(tce_page) = tcep;
@@ -449,7 +453,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
/* error cleanup: caller will clear whole range */
- local_irq_enable();
+ local_unlock_irq(tcp_page_lock);
return rc;
}
--
2.14.1
