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Message-Id: <1390189486-13579-2-git-send-email-nab@linux-iscsi.org>
Date: Mon, 20 Jan 2014 03:44:44 +0000
From: "Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To: target-devel <target-devel@...r.kernel.org>
Cc: linux-kernel <linux-kernel@...r.kernel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Kent Overstreet <kmo@...erainc.com>,
Jens Axboe <axboe@...nel.dk>
Subject: [PATCH-v2 1/3] percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask
From: Kent Overstreet <kmo@...erainc.com>
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
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>
Cc: <stable@...r.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
---
block/blk-mq-tag.c | 6 ++++--
drivers/target/iscsi/iscsi_target_util.c | 8 ++++++--
drivers/target/tcm_fc/tfc_cmd.c | 2 +-
drivers/vhost/scsi.c | 2 +-
include/linux/percpu_ida.h | 3 ++-
lib/percpu_ida.c | 12 ++++++------
6 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d64a02f..5d70edc 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -36,7 +36,8 @@ static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp)
{
int tag;
- tag = percpu_ida_alloc(&tags->free_tags, gfp);
+ tag = percpu_ida_alloc(&tags->free_tags, (gfp & __GFP_WAIT) ?
+ TASK_UNINTERRUPTIBLE : TASK_RUNNING);
if (tag < 0)
return BLK_MQ_TAG_FAIL;
return tag + tags->nr_reserved_tags;
@@ -52,7 +53,8 @@ static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags,
return BLK_MQ_TAG_FAIL;
}
- tag = percpu_ida_alloc(&tags->reserved_tags, gfp);
+ tag = percpu_ida_alloc(&tags->reserved_tags, (gfp & __GFP_WAIT) ?
+ TASK_UNINTERRUPTIBLE : TASK_RUNNING);
if (tag < 0)
return BLK_MQ_TAG_FAIL;
return tag;
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 0819e68..9b8e1db 100644
--- 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(struct iscsi_conn *conn, gfp_t gfp_mask)
{
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);
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index 479ec56..8b2c1aa 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -438,7 +438,7 @@ static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
struct se_session *se_sess = sess->se_sess;
int tag;
- 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)
goto busy;
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 84488a8..2d084fb 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -728,7 +728,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq,
}
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);
diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h
index 1900bd0..f5cfdd6 100644
--- 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>
@@ -61,7 +62,7 @@ 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(struct percpu_ida *pool, int state);
void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
void percpu_ida_destroy(struct percpu_ida *pool);
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 9d054bf..a48ce2e 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -132,22 +132,22 @@ static inline unsigned alloc_local_tag(struct percpu_ida_cpu *tags)
/**
* 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;
@@ -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);
@@ -191,7 +191,7 @@ 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;
schedule();
--
1.7.10.4
--
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