From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com, stable-rt@vger.kernel.org
Subject: [PATCH RT 1/6] powerpc/pseries/iommu: Use a locallock instead local_irq_save()
Date: Fri, 24 May 2019 23:32:33 -0400 [thread overview]
Message-ID: <20190525033315.333596820@goodmis.org> (raw)
In-Reply-To: 20190525033232.795741612@goodmis.org
4.19.37-rt20-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
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 06f02960b439..d80d919c78d3 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -38,6 +38,7 @@
#include <linux/of.h>
#include <linux/iommu.h>
#include <linux/rculist.h>
+#include <linux/locallock.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/rtas.h>
@@ -212,6 +213,7 @@ 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,
@@ -232,7 +234,8 @@ 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 = __this_cpu_read(tce_page);
@@ -243,7 +246,7 @@ 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);
}
@@ -277,7 +280,7 @@ 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;
@@ -435,13 +438,14 @@ 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 = __this_cpu_read(tce_page);
if (!tcep) {
tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
if (!tcep) {
- local_irq_enable();
+ local_unlock_irq(tcp_page_lock);
return -ENOMEM;
}
__this_cpu_write(tce_page, tcep);
@@ -487,7 +491,7 @@ 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;
}
--
2.20.1
next prev parent reply other threads:[~2019-05-25 3:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 3:32 [PATCH RT 0/6] Linux 4.19.37-rt20-rc1 Steven Rostedt
2019-05-25 3:32 ` Steven Rostedt [this message]
2019-05-25 3:32 ` [PATCH RT 2/6] powerpc: reshuffle TIF bits Steven Rostedt
2019-05-25 3:32 ` [PATCH RT 3/6] tty/sysrq: Convert show_lock to raw_spinlock_t Steven Rostedt
2019-05-25 3:32 ` [PATCH RT 4/6] drm/i915: Dont disable interrupts independently of the lock Steven Rostedt
2019-05-25 3:32 ` [PATCH RT 5/6] sched/completion: Fix a lockup in wait_for_completion() Steven Rostedt
2019-05-25 3:32 ` [PATCH RT 6/6] Linux 4.19.37-rt20-rc1 Steven Rostedt
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