From: Kent Overstreet <k...@daterainc.com>
This patch adds an tag allocation interface that allows for
interruptible sleep with GFP_KERNEL, instead of always assuming
uninterruptible sleep preventing a signal from being delivered
to a scheduled process context in the tag stealing slow path.
This includes a wrapper for backwards compatiblity with
existing percpu_ida_alloc() consumers.
Signed-off-by: Kent Overstreet <k...@daterainc.com>
Signed-off-by: Nicholas Bellinger <n...@linux-iscsi.org>
---
include/linux/percpu_ida.h | 11 ++++++++++-
lib/percpu_ida.c | 13 +++++++++----
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h
index 1900bd0..bcf31a5 100644
--- a/include/linux/percpu_ida.h
+++ b/include/linux/percpu_ida.h
@@ -3,7 +3,9 @@
#include <linux/types.h>
#include <linux/bitops.h>
+#include <linux/gfp.h>
#include <linux/init.h>
+#include <linux/sched.h>
#include <linux/spinlock_types.h>
#include <linux/wait.h>
#include <linux/cpumask.h>
@@ -61,9 +63,16 @@ struct percpu_ida {
/* Max size of percpu freelist, */
#define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
-int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp);
+int percpu_ida_alloc_state(struct percpu_ida *pool, int state);
void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
+static inline int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
+{
+ return percpu_ida_alloc_state(pool, (gfp & __GFP_WAIT)
+ ? TASK_UNINTERRUPTIBLE
+ : TASK_RUNNING);
+}
+
void percpu_ida_destroy(struct percpu_ida *pool);
int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
unsigned long max_size, unsigned long batch_size);
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 9d054bf..58b2268 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -147,7 +147,7 @@ static inline unsigned alloc_local_tag(struct
percpu_ida_cpu *tags)
*
* Will not fail if passed __GFP_WAIT.
*/
-int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
+int percpu_ida_alloc_state(struct percpu_ida *pool, int state)
{
DEFINE_WAIT(wait);
struct percpu_ida_cpu *tags;
@@ -174,7 +174,7 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
*
* global lock held and irqs disabled, don't need percpu lock
*/
- prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
+ prepare_to_wait(&pool->wait, &wait, state);
if (!tags->nr_free)
alloc_global_tags(pool, tags);
@@ -191,9 +191,14 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
spin_unlock(&pool->lock);
local_irq_restore(flags);
- if (tag >= 0 || !(gfp & __GFP_WAIT))
+ if (tag >= 0 || state == TASK_RUNNING)
break;
+ if (signal_pending_state(state, current)) {
+ tag = -ERESTARTSYS;
+ break;
+ }
+
schedule();
local_irq_save(flags);
@@ -203,7 +208,7 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
finish_wait(&pool->wait, &wait);
return tag;
}
-EXPORT_SYMBOL_GPL(percpu_ida_alloc);
+EXPORT_SYMBOL_GPL(percpu_ida_alloc_state);
/**
* percpu_ida_free - free a tag
--
1.7.10.4
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