From: Nicholas Bellinger <n...@linux-iscsi.org>
This patch addresses a bug where connection reset would hang
indefinately once percpu_ida_alloc() was starved for tags, due
to the fact that it always assumed uninterruptible sleep mode.
So now make percpu_ida_alloc() check for signal_pending_state() for
making interruptible sleep optional, and convert iscsit_allocate_cmd()
to set TASK_INTERRUPTIBLE for GFP_KERNEL, or TASK_RUNNING for
GFP_ATOMIC.
Reported-by: Linus Torvalds <torva...@linux-foundation.org>
Cc: Kent Overstreet <k...@daterainc.com>
Cc: <sta...@vger.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <n...@linux-iscsi.org>
---
drivers/target/iscsi/iscsi_target_util.c | 2 +-
lib/percpu_ida.c | 9 +++++++--
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target_util.c
b/drivers/target/iscsi/iscsi_target_util.c
index 9b8e1db..5477eca 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -156,7 +156,7 @@ 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, state = (gfp_mask & __GFP_WAIT) ? TASK_UNINTERRUPTIBLE :
+ int size, tag, state = (gfp_mask & __GFP_WAIT) ? TASK_INTERRUPTIBLE :
TASK_RUNNING;
tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index a48ce2e..a667110 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -138,14 +138,14 @@ static inline unsigned alloc_local_tag(struct
percpu_ida_cpu *tags)
* tag_pool_init()), or otherwise -ENOSPC on allocation failure.
*
* Safe to be called from interrupt context (assuming it isn't passed
- * TASK_UNINTERRUPTIBLE, of course).
+ * TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 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 TASK_UNINTERRUPTIBLE.
+ * Will not fail if passed TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE.
*/
int percpu_ida_alloc(struct percpu_ida *pool, int state)
{
@@ -194,6 +194,11 @@ int percpu_ida_alloc(struct percpu_ida *pool, int state)
if (tag >= 0 || state == TASK_RUNNING)
break;
+ if (signal_pending_state(state, current)) {
+ tag = -ERESTARTSYS;
+ break;
+ }
+
schedule();
local_irq_save(flags);
--
1.7.10.4
--
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