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Message-Id: <20140211184749.882428337@linuxfoundation.org>
Date: Tue, 11 Feb 2014 11:05:25 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Jens Axboe <axboe@...nel.dk>,
Kent Overstreet <kmo@...erainc.com>,
Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [PATCH 3.12 059/107] percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask
3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kent Overstreet <kmo@...erainc.com>
commit 6f6b5d1ec56acdeab0503d2b823f6f88a0af493e upstream.
This patch changes percpu_ida_alloc() + callers to accept task state
bitmask for prepare_to_wait() for code like target/iscsi that needs
it for interruptible sleep, that is provided in a subsequent patch.
It now expects TASK_UNINTERRUPTIBLE when the caller is able to sleep
waiting for a new tag, or TASK_RUNNING when the caller cannot sleep,
and is forced to return a negative value when no tags are available.
v2 changes:
- Include blk-mq + tcm_fc + vhost/scsi + target/iscsi changes
- Drop signal_pending_state() call
v3 changes:
- Only call prepare_to_wait() + finish_wait() when != TASK_RUNNING
(PeterZ)
Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Kent Overstreet <kmo@...erainc.com>
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/target/iscsi/iscsi_target_util.c | 8 ++++++--
drivers/vhost/scsi.c | 2 +-
include/linux/percpu_ida.h | 3 ++-
lib/percpu_ida.c | 16 +++++++++-------
4 files changed, 18 insertions(+), 11 deletions(-)
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -156,9 +156,13 @@ struct iscsi_cmd *iscsit_allocate_cmd(st
{
struct iscsi_cmd *cmd;
struct se_session *se_sess = conn->sess->se_sess;
- int size, tag;
+ int size, tag, state = (gfp_mask & __GFP_WAIT) ? TASK_UNINTERRUPTIBLE :
+ TASK_RUNNING;
+
+ tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
+ if (tag < 0)
+ return NULL;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, gfp_mask);
size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
memset(cmd, 0, size);
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -728,7 +728,7 @@ vhost_scsi_get_tag(struct vhost_virtqueu
}
se_sess = tv_nexus->tvn_se_sess;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC);
+ tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
if (tag < 0) {
pr_err("Unable to obtain tag for tcm_vhost_cmd\n");
return ERR_PTR(-ENOMEM);
--- a/include/linux/percpu_ida.h
+++ b/include/linux/percpu_ida.h
@@ -4,6 +4,7 @@
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/init.h>
+#include <linux/sched.h>
#include <linux/spinlock_types.h>
#include <linux/wait.h>
#include <linux/cpumask.h>
@@ -51,7 +52,7 @@ struct percpu_ida {
} ____cacheline_aligned_in_smp;
};
-int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp);
+int percpu_ida_alloc(struct percpu_ida *pool, int state);
void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
void percpu_ida_destroy(struct percpu_ida *pool);
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -142,22 +142,22 @@ static inline unsigned alloc_local_tag(s
/**
* percpu_ida_alloc - allocate a tag
* @pool: pool to allocate from
- * @gfp: gfp flags
+ * @state: task state for prepare_to_wait
*
* Returns a tag - an integer in the range [0..nr_tags) (passed to
* tag_pool_init()), or otherwise -ENOSPC on allocation failure.
*
* Safe to be called from interrupt context (assuming it isn't passed
- * __GFP_WAIT, of course).
+ * TASK_UNINTERRUPTIBLE, of course).
*
* @gfp indicates whether or not to wait until a free id is available (it's not
* used for internal memory allocations); thus if passed __GFP_WAIT we may sleep
* however long it takes until another thread frees an id (same semantics as a
* mempool).
*
- * Will not fail if passed __GFP_WAIT.
+ * Will not fail if passed TASK_UNINTERRUPTIBLE.
*/
-int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
+int percpu_ida_alloc(struct percpu_ida *pool, int state)
{
DEFINE_WAIT(wait);
struct percpu_ida_cpu *tags;
@@ -184,7 +184,8 @@ int percpu_ida_alloc(struct percpu_ida *
*
* global lock held and irqs disabled, don't need percpu lock
*/
- prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
+ if (state != TASK_RUNNING)
+ prepare_to_wait(&pool->wait, &wait, state);
if (!tags->nr_free)
alloc_global_tags(pool, tags);
@@ -201,7 +202,7 @@ int percpu_ida_alloc(struct percpu_ida *
spin_unlock(&pool->lock);
local_irq_restore(flags);
- if (tag >= 0 || !(gfp & __GFP_WAIT))
+ if (tag >= 0 || state == TASK_RUNNING)
break;
schedule();
@@ -209,8 +210,9 @@ int percpu_ida_alloc(struct percpu_ida *
local_irq_save(flags);
tags = this_cpu_ptr(pool->tag_cpu);
}
+ if (state != TASK_RUNNING)
+ finish_wait(&pool->wait, &wait);
- finish_wait(&pool->wait, &wait);
return tag;
}
EXPORT_SYMBOL_GPL(percpu_ida_alloc);
--
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