iscsi-target: Fix connection reset hang with percpu_ida_alloc
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 <torvalds@linux-foundation.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 58b6714..7be235f 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -138,14 +138,14 @@
* 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)
{
@@ -195,6 +195,11 @@
if (tag >= 0 || state == TASK_RUNNING)
break;
+ if (signal_pending_state(state, current)) {
+ tag = -ERESTARTSYS;
+ break;
+ }
+
schedule();
local_irq_save(flags);