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ib_srpt: Remove "thread" kernel module parameter and keep thread=1 behavior - the other two modes could cause soft lockup complaints

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git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@3535 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2011-06-04 17:50:19 +00:00
parent edf466ba9f
commit c2bd2e8bf5
2 changed files with 10 additions and 98 deletions
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srpt/src/ib_srpt.c
+10 -82
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@@ -75,17 +75,6 @@ MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol target "
"v" DRV_VERSION " (" DRV_RELDATE ")");
MODULE_LICENSE("Dual BSD/GPL");
/*
* Local data types.
*/
enum threading_mode {
MODE_ALL_IN_SIRQ = 0,
MODE_IB_COMPLETION_IN_THREAD = 1,
MODE_IB_COMPLETION_IN_SIRQ = 2,
};
/*
* Global Variables
*/
@@ -99,15 +88,6 @@ module_param(trace_flag, long, 0644);
MODULE_PARM_DESC(trace_flag, "SCST trace flags.");
#endif
static int thread = 1;
module_param(thread, int, 0444);
MODULE_PARM_DESC(thread,
"IB completion and SCSI command processing context. Defaults"
" to one, i.e. process IB completions and SCSI commands in"
" kernel thread context. 0 means soft IRQ whenever possible"
" and 2 means process IB completions in soft IRQ context and"
" SCSI commands in kernel thread context.");
static unsigned srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
module_param(srp_max_rdma_size, int, 0744);
MODULE_PARM_DESC(srp_max_rdma_size,
@@ -1892,33 +1872,12 @@ static void srpt_process_completion(struct ib_cq *cq,
/**
* srpt_completion() - IB completion queue callback function.
*
* Notes:
* - It is guaranteed that a completion handler will never be invoked
* concurrently on two different CPUs for the same completion queue. See also
* Documentation/infiniband/core_locking.txt and the implementation of
* handle_edge_irq() in kernel/irq/chip.c.
* - When threaded IRQs are enabled, completion handlers are invoked in thread
* context instead of interrupt context.
*/
static void srpt_completion(struct ib_cq *cq, void *ctx)
{
struct srpt_rdma_ch *ch = ctx;
BUG_ON(!ch);
switch (thread) {
case MODE_IB_COMPLETION_IN_THREAD:
wake_up_process(ch->thread);
break;
case MODE_IB_COMPLETION_IN_SIRQ:
srpt_process_completion(cq, ch, SCST_CONTEXT_THREAD,
SCST_CONTEXT_THREAD);
break;
case MODE_ALL_IN_SIRQ:
srpt_process_completion(cq, ch, SCST_CONTEXT_TASKLET,
SCST_CONTEXT_TASKLET);
break;
}
wake_up_process(ch->thread);
}
static int srpt_compl_thread(void *arg)
@@ -1999,20 +1958,16 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
if (ret)
goto err_destroy_qp;
if (thread == MODE_IB_COMPLETION_IN_THREAD) {
TRACE_DBG("creating IB completion thread for session %s",
ch->sess_name);
TRACE_DBG("creating IB completion thread for session %s",
ch->sess_name);
ch->thread = kthread_run(srpt_compl_thread, ch,
"ib_srpt_compl");
if (IS_ERR(ch->thread)) {
PRINT_ERROR("failed to create kernel thread %ld",
PTR_ERR(ch->thread));
ch->thread = NULL;
goto err_destroy_qp;
}
} else
ib_req_notify_cq(ch->cq, IB_CQ_NEXT_COMP);
ch->thread = kthread_run(srpt_compl_thread, ch, "ib_srpt_compl");
if (IS_ERR(ch->thread)) {
PRINT_ERROR("failed to create kernel thread %ld",
PTR_ERR(ch->thread));
ch->thread = NULL;
goto err_destroy_qp;
}
out:
kfree(qp_init);
@@ -3972,33 +3927,6 @@ static int __init srpt_init_module(void)
}
#endif
switch (thread) {
case MODE_ALL_IN_SIRQ:
/*
* Process both IB completions and SCST commands in SIRQ
* context. May lead to soft lockups and other scary behavior
* under sufficient load.
*/
srpt_template.rdy_to_xfer_atomic = true;
break;
case MODE_IB_COMPLETION_IN_THREAD:
/*
* Process IB completions in the kernel thread associated with
* the RDMA channel, and process SCST commands in the kernel
* threads created by the SCST core.
*/
srpt_template.rdy_to_xfer_atomic = false;
break;
case MODE_IB_COMPLETION_IN_SIRQ:
default:
/*
* Process IB completions in SIRQ context and SCST commands in
* the kernel threads created by the SCST core.
*/
srpt_template.rdy_to_xfer_atomic = false;
break;
}
ret = scst_register_target_template(&srpt_template);
if (ret < 0) {
PRINT_ERROR("%s", "couldn't register with scst");