Hi Bob,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on c9eeabac5e8d27a3f40280908e089058bab39edb]

url:    https://github.com/intel-lab-lkp/linux/commits/Bob-Pearson/RDMA-rxe-Enable-scatter-gather-support-for-skbs/20221028-025839
base:   c9eeabac5e8d27a3f40280908e089058bab39edb
patch link:    https://lore.kernel.org/r/20221027185510.33808-4-rpearsonhpe%40gmail.com
patch subject: [PATCH for-next 03/17] RDMA/rxe: Isolate code to build request packet
config: arm64-allyesconfig
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/574d2b0517821f3c83c7962814b820a6880e2224
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Bob-Pearson/RDMA-rxe-Enable-scatter-gather-support-for-skbs/20221028-025839
        git checkout 574d2b0517821f3c83c7962814b820a6880e2224
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/infiniband/sw/rxe/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/infiniband/sw/rxe/rxe_req.c:482:6: warning: variable 'skb' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (unlikely(!av))
               ^~~~~~~~~~~~~
   include/linux/compiler.h:78:22: note: expanded from macro 'unlikely'
   # define unlikely(x)    __builtin_expect(!!(x), 0)
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/infiniband/sw/rxe/rxe_req.c:523:6: note: uninitialized use occurs here
           if (skb)
               ^~~
   drivers/infiniband/sw/rxe/rxe_req.c:482:2: note: remove the 'if' if its condition is always false
           if (unlikely(!av))
           ^~~~~~~~~~~~~~~~~~
   drivers/infiniband/sw/rxe/rxe_req.c:465:21: note: initialize the variable 'skb' to silence this warning
           struct sk_buff *skb;
                              ^
                               = NULL
   1 warning generated.


vim +482 drivers/infiniband/sw/rxe/rxe_req.c

   458	
   459	static struct sk_buff *rxe_init_req_packet(struct rxe_qp *qp,
   460						   struct rxe_send_wqe *wqe,
   461						   int opcode, u32 payload,
   462						   struct rxe_pkt_info *pkt)
   463	{
   464		struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
   465		struct sk_buff *skb;
   466		struct rxe_av *av;
   467		struct rxe_ah *ah;
   468		void *padp;
   469		int pad;
   470		int err = -EINVAL;
   471	
   472		pkt->rxe = rxe;
   473		pkt->opcode = opcode;
   474		pkt->qp = qp;
   475		pkt->psn = qp->req.psn;
   476		pkt->mask = rxe_opcode[opcode].mask;
   477		pkt->wqe = wqe;
   478		pkt->port_num = 1;
   479	
   480		/* get address vector and address handle for UD qps only */
   481		av = rxe_get_av(pkt, &ah);
 > 482		if (unlikely(!av))
   483			goto err_out;
   484	
   485		/* length from start of bth to end of icrc */
   486		pad = (-payload) & 0x3;
   487		pkt->paylen = rxe_opcode[opcode].length + payload +
   488							pad + RXE_ICRC_SIZE;
   489	
   490		/* init skb */
   491		skb = rxe_init_packet(rxe, av, pkt);
   492		if (unlikely(!skb))
   493			goto err_out;
   494	
   495		rxe_init_roce_hdrs(qp, wqe, pkt, pad);
   496	
   497		if (pkt->mask & RXE_WRITE_OR_SEND_MASK) {
   498			err = rxe_init_payload(qp, wqe, pkt, payload);
   499			if (err)
   500				goto err_out;
   501		}
   502	
   503		if (pad) {
   504			padp = payload_addr(pkt) + payload;
   505			memset(padp, 0, pad);
   506		}
   507	
   508		/* IP and UDP network headers */
   509		err = rxe_prepare(av, pkt, skb);
   510		if (err)
   511			goto err_out;
   512	
   513		if (ah)
   514			rxe_put(ah);
   515	
   516		return skb;
   517	
   518	err_out:
   519		if (err == -EFAULT)
   520			wqe->status = IB_WC_LOC_PROT_ERR;
   521		else
   522			wqe->status = IB_WC_LOC_QP_OP_ERR;
   523		if (skb)
   524			kfree_skb(skb);
   525		if (ah)
   526			rxe_put(ah);
   527	
   528		return NULL;
   529	}
   530	

-- 
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https://01.org/lkp