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Message-ID: <20151027181235.GA27038@phlsvsds.ph.intel.com>
Date: Tue, 27 Oct 2015 14:12:36 -0400
From: "ira.weiny" <ira.weiny@...el.com>
To: Saurabh Sengar <saurabh.truth@...il.com>
Cc: dledford@...hat.com, sean.hefty@...el.com,
hal.rosenstock@...il.com, jgunthorpe@...idianresearch.com,
yun.wang@...fitbricks.com, kaike.wan@...el.com,
linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] IB/sa: replace GFP_KERNEL with GFP_ATOMIC
On Tue, Oct 27, 2015 at 09:17:40PM +0530, Saurabh Sengar wrote:
> replace GFP_KERNEL with GFP_ATOMIC, as code while holding a spinlock
> should be atomic
> GFP_KERNEL may sleep and can cause deadlock, where as GFP_ATOMIC may
> fail but certainly avoids deadlock
Great catch. Thanks!
However, gfp_t is passed to send_mad and we should pass that down and use it.
Compile tested only, suggestion below,
Ira
14:09:12 > git di
diff --git a/drivers/infiniband/core/sa_query.c
b/drivers/infiniband/core/sa_query.c
index 8c014b33d8e0..54d454042b28 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -512,7 +512,7 @@ static int ib_nl_get_path_rec_attrs_len(ib_sa_comp_mask comp_mask)
return len;
}
-static int ib_nl_send_msg(struct ib_sa_query *query)
+static int ib_nl_send_msg(struct ib_sa_query *query, gfp_t gfp_mask)
{
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh;
@@ -526,7 +526,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
if (len <= 0)
return -EMSGSIZE;
- skb = nlmsg_new(len, GFP_KERNEL);
+ skb = nlmsg_new(len, gfp_mask);
if (!skb)
return -ENOMEM;
@@ -544,7 +544,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
/* Repair the nlmsg header length */
nlmsg_end(skb, nlh);
- ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, GFP_KERNEL);
+ ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, gfp_mask);
if (!ret)
ret = len;
else
@@ -553,7 +553,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
return ret;
}
-static int ib_nl_make_request(struct ib_sa_query *query)
+static int ib_nl_make_request(struct ib_sa_query *query, gfp_t gfp_mask)
{
unsigned long flags;
unsigned long delay;
@@ -563,7 +563,7 @@ static int ib_nl_make_request(struct ib_sa_query *query)
query->seq = (u32)atomic_inc_return(&ib_nl_sa_request_seq);
spin_lock_irqsave(&ib_nl_request_lock, flags);
- ret = ib_nl_send_msg(query);
+ ret = ib_nl_send_msg(query, gfp_mask);
if (ret <= 0) {
ret = -EIO;
goto request_out;
@@ -1105,7 +1105,7 @@ static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask)
if (query->flags & IB_SA_ENABLE_LOCAL_SERVICE) {
if (!ibnl_chk_listeners(RDMA_NL_GROUP_LS)) {
- if (!ib_nl_make_request(query))
+ if (!ib_nl_make_request(query, gfp_mask))
return id;
}
ib_sa_disable_local_svc(query);
--
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