Hi Greg,
On Tue, 2014-02-04 at 10:11 -0800, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> The patch below does not apply to the 3.12-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
Just sent out the 'for-v3.12.y' series for this, including the preceding
(slightly modified) dependency:
percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask
Please apply for v3.12.y.
Thank you,
--nab
> ------------------ original commit in Linus's tree ------------------
>
> From 555b270e25b0279b98083518a85f4b1da144a181 Mon Sep 17 00:00:00 2001
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> Date: Mon, 20 Jan 2014 03:36:24 +0000
> Subject: [PATCH] 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@xxxxxxxxxxxxxxxxxxxx>
> Cc: Kent Overstreet <kmo@xxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> #3.12+
> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
> index 9b8e1db1257b..5477ecabc00e 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 58b671484ac2..7be235f1a70b 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)
> {
> @@ -195,6 +195,11 @@ 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);
>
--
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