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IB/sa: Put netlink request into the request list before sending

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It was found by Saurabh Sengar that the netlink code tried to allocate
memory with GFP_KERNEL while holding a spinlock. While it is possible
to fix the issue by replacing GFP_KERNEL with GFP_ATOMIC, it is better
to get rid of the spinlock while sending the packet. However, in order
to protect against a race condition that a quick response may be received
before the request is put on the request list, we need to put the request
on the list first.

Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reported-by: Saurabh Sengar <saurabh.truth@gmail.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Kaike Wan 2015-10-30 08:23:45 -04:00 committed by Doug Ledford
parent 2c63d1072a
commit 3ebd2fd0d0
1 changed files with 17 additions and 15 deletions
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32
drivers/infiniband/core/sa_query.c
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@ -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;
@ -562,25 +562,27 @@ static int ib_nl_make_request(struct ib_sa_query *query)
INIT_LIST_HEAD(&query->list);
query->seq = (u32)atomic_inc_return(&ib_nl_sa_request_seq);
/* Put the request on the list first.*/
spin_lock_irqsave(&ib_nl_request_lock, flags);
ret = ib_nl_send_msg(query);
if (ret <= 0) {
ret = -EIO;
goto request_out;
} else {
ret = 0;
}
delay = msecs_to_jiffies(sa_local_svc_timeout_ms);
query->timeout = delay + jiffies;
list_add_tail(&query->list, &ib_nl_request_list);
/* Start the timeout if this is the only request */
if (ib_nl_request_list.next == &query->list)
queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, delay);
request_out:
spin_unlock_irqrestore(&ib_nl_request_lock, flags);
ret = ib_nl_send_msg(query, gfp_mask);
if (ret <= 0) {
ret = -EIO;
/* Remove the request */
spin_lock_irqsave(&ib_nl_request_lock, flags);
list_del(&query->list);
spin_unlock_irqrestore(&ib_nl_request_lock, flags);
} else {
ret = 0;
}
return ret;
}
@ -1108,7 +1110,7 @@ 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);