This fixes a deadlock added with commit b40f3894e3 ("scsi: qedi: Complete
TMF works before disconnect")
Bug description from Jia-Ju Bai:
qedi_process_tmf_resp()
spin_lock(&session->back_lock); --> Line 201 (Lock A)
spin_lock(&qedi_conn->tmf_work_lock); --> Line 230 (Lock B)
qedi_process_cmd_cleanup_resp()
spin_lock_bh(&qedi_conn->tmf_work_lock); --> Line 752 (Lock B)
spin_lock_bh(&conn->session->back_lock); --> Line 784 (Lock A)
When qedi_process_tmf_resp() and qedi_process_cmd_cleanup_resp() are
concurrently executed, the deadlock can occur.
This patch fixes the deadlock by not holding the tmf_work_lock in
qedi_process_cmd_cleanup_resp while holding the back_lock. The
tmf_work_lock is only needed while we remove the tmf_work from the
work_list.
Link: https://lore.kernel.org/r/20220208185448.6206-1-michael.christie@oracle.com
Fixes: b40f3894e3 ("scsi: qedi: Complete TMF works before disconnect")
Cc: Manish Rangankar <mrangankar@marvell.com>
Cc: Nilesh Javali <njavali@marvell.com>
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
f10f582d28