forked from Minki/linux
IB/sa: Put netlink request into the request list before sending
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>
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2c63d1072a
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3ebd2fd0d0
@ -512,7 +512,7 @@ static int ib_nl_get_path_rec_attrs_len(ib_sa_comp_mask comp_mask)
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return len;
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}
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static int ib_nl_send_msg(struct ib_sa_query *query)
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static int ib_nl_send_msg(struct ib_sa_query *query, gfp_t gfp_mask)
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{
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struct sk_buff *skb = NULL;
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struct nlmsghdr *nlh;
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@ -526,7 +526,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
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if (len <= 0)
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return -EMSGSIZE;
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skb = nlmsg_new(len, GFP_KERNEL);
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skb = nlmsg_new(len, gfp_mask);
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if (!skb)
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return -ENOMEM;
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@ -544,7 +544,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
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/* Repair the nlmsg header length */
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nlmsg_end(skb, nlh);
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ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, GFP_KERNEL);
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ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, gfp_mask);
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if (!ret)
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ret = len;
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else
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@ -553,7 +553,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query)
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return ret;
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}
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static int ib_nl_make_request(struct ib_sa_query *query)
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static int ib_nl_make_request(struct ib_sa_query *query, gfp_t gfp_mask)
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{
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unsigned long flags;
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unsigned long delay;
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@ -562,25 +562,27 @@ static int ib_nl_make_request(struct ib_sa_query *query)
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INIT_LIST_HEAD(&query->list);
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query->seq = (u32)atomic_inc_return(&ib_nl_sa_request_seq);
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/* Put the request on the list first.*/
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spin_lock_irqsave(&ib_nl_request_lock, flags);
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ret = ib_nl_send_msg(query);
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if (ret <= 0) {
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ret = -EIO;
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goto request_out;
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} else {
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ret = 0;
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}
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delay = msecs_to_jiffies(sa_local_svc_timeout_ms);
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query->timeout = delay + jiffies;
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list_add_tail(&query->list, &ib_nl_request_list);
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/* Start the timeout if this is the only request */
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if (ib_nl_request_list.next == &query->list)
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queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, delay);
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request_out:
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spin_unlock_irqrestore(&ib_nl_request_lock, flags);
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ret = ib_nl_send_msg(query, gfp_mask);
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if (ret <= 0) {
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ret = -EIO;
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/* Remove the request */
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spin_lock_irqsave(&ib_nl_request_lock, flags);
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list_del(&query->list);
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spin_unlock_irqrestore(&ib_nl_request_lock, flags);
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} else {
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ret = 0;
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}
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return ret;
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}
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@ -1108,7 +1110,7 @@ static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask)
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if (query->flags & IB_SA_ENABLE_LOCAL_SERVICE) {
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if (!ibnl_chk_listeners(RDMA_NL_GROUP_LS)) {
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if (!ib_nl_make_request(query))
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if (!ib_nl_make_request(query, gfp_mask))
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return id;
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}
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ib_sa_disable_local_svc(query);
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