The first invocation of function find_first_zero_bit will return 0 and
queue_id gets set to 0.

An index of queue_pair_map also gets set to 0.

	qpair_id = find_first_zero_bit(ha->qpair_qid_map, ha->max_qpairs);

        set_bit(qpair_id, ha->qpair_qid_map);
        ha->queue_pair_map[qpair_id] = qpair;

In the alloc_queue callback driver checks the map, if queue is already
allocated:

	ha->queue_pair_map[qidx]

This works fine as long as max_qpairs is greater than nvme_max_hw_queues(8)
since the size of the queue_pair_map is equal to max_qpair. In case nr_cpus
is less than 8, max_qpairs is less than 8. This creates wrong value
returned as qpair.

[ 1572.353669] qla2xxx [0000:24:00.3]-2121:6: Returning existing qpair of 4e00000000000000 for idx=2
[ 1572.354458] general protection fault: 0000 [#1] SMP PTI
[ 1572.354461] CPU: 1 PID: 44 Comm: kworker/1:1H Kdump: loaded Tainted: G          IOE    --------- -  - 4.18.0-304.el8.x86_64 #1
[ 1572.354462] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 03/01/2013
[ 1572.354467] Workqueue: kblockd blk_mq_run_work_fn
[ 1572.354485] RIP: 0010:qla_nvme_post_cmd+0x92/0x760 [qla2xxx]
[ 1572.354486] Code: 84 24 5c 01 00 00 00 00 b8 0a 74 1e 66 83 79 48 00 0f 85 a8 03 00 00 48 8b 44 24 08 48 89 ee 4c 89 e7 8b 50 24 e8 5e 8e 00 00 <f0> 41 ff 47 04 0f ae f0 41 f6 47 24 04 74 19 f0 41 ff 4f 04 b8 f0
[ 1572.354487] RSP: 0018:ffff9c81c645fc90 EFLAGS: 00010246
[ 1572.354489] RAX: 0000000000000001 RBX: ffff8ea3e5070138 RCX: 0000000000000001
[ 1572.354490] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8ea4c866b800
[ 1572.354491] RBP: ffff8ea4c866b800 R08: 0000000000005010 R09: ffff8ea4c866b800
[ 1572.354492] R10: 0000000000000001 R11: 000000069d1ca3ff R12: ffff8ea4bc460000
[ 1572.354493] R13: ffff8ea3e50702b0 R14: ffff8ea4c4c16a58 R15: 4e00000000000000
[ 1572.354494] FS:  0000000000000000(0000) GS:ffff8ea4dfd00000(0000) knlGS:0000000000000000
[ 1572.354495] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1572.354496] CR2: 000055884504fa58 CR3: 00000005a1410001 CR4: 00000000000606e0
[ 1572.354497] Call Trace:
[ 1572.354503]  ? check_preempt_curr+0x62/0x90
[ 1572.354506]  ? dma_direct_map_sg+0x72/0x1f0
[ 1572.354509]  ? nvme_fc_start_fcp_op.part.32+0x175/0x460 [nvme_fc]
[ 1572.354511]  ? blk_mq_dispatch_rq_list+0x11c/0x730
[ 1572.354515]  ? __switch_to_asm+0x35/0x70
[ 1572.354516]  ? __switch_to_asm+0x41/0x70
[ 1572.354518]  ? __switch_to_asm+0x35/0x70
[ 1572.354519]  ? __switch_to_asm+0x41/0x70
[ 1572.354521]  ? __switch_to_asm+0x35/0x70
[ 1572.354522]  ? __switch_to_asm+0x41/0x70
[ 1572.354523]  ? __switch_to_asm+0x35/0x70
[ 1572.354525]  ? entry_SYSCALL_64_after_hwframe+0xb9/0xca
[ 1572.354527]  ? __switch_to_asm+0x41/0x70
[ 1572.354529]  ? __blk_mq_sched_dispatch_requests+0xc6/0x170
[ 1572.354531]  ? blk_mq_sched_dispatch_requests+0x30/0x60
[ 1572.354532]  ? __blk_mq_run_hw_queue+0x51/0xd0
[ 1572.354535]  ? process_one_work+0x1a7/0x360
[ 1572.354537]  ? create_worker+0x1a0/0x1a0
[ 1572.354538]  ? worker_thread+0x30/0x390
[ 1572.354540]  ? create_worker+0x1a0/0x1a0
[ 1572.354541]  ? kthread+0x116/0x130
[ 1572.354543]  ? kthread_flush_work_fn+0x10/0x10
[ 1572.354545]  ? ret_from_fork+0x35/0x40

Fix is to use index 0 for admin and first IO queue.

Link: https://lore.kernel.org/r/20210810043720.1137-14-njavali@marvell.com
Fixes: e84067d7 ("scsi: qla2xxx: Add FC-NVMe F/W initialization and transport registration")
Cc: stable@vger.kernel.org
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>