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| author | Adrien Thierry <athierry@redhat.com> | 2023-02-17 14:44:22 -0500 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2023-02-21 18:09:30 -0500 |
| commit | 7dafc3e007918384c8693ff8d70381b5c1e9c247 (patch) | |
| tree | 7b87477bc33d42539c84eef62d05de4732486737 /include/ufs | |
| parent | 473025a6b6f8a4a8de3120c78588d32cf4ba7324 (diff) | |
scsi: ufs: core: Initialize devfreq synchronously
During UFS initialization, devfreq initialization is asynchronous:
ufshcd_async_scan() calls ufshcd_add_lus(), which in turn initializes
devfreq for UFS. The simple ondemand governor is then loaded. If it is
built as a module, request_module() is called and throws a warning:
WARNING: CPU: 7 PID: 167 at kernel/kmod.c:136 __request_module+0x1e0/0x460
Modules linked in: crct10dif_ce llcc_qcom phy_qcom_qmp_usb ufs_qcom phy_qcom_snps_femto_v2 ufshcd_pltfrm phy_qcom_qmp_combo ufshcd_core phy_qcom_qmp_ufs qcom_wdt socinfo fuse ipv6
CPU: 7 PID: 167 Comm: kworker/u16:3 Not tainted 6.2.0-rc6-00009-g58706f7fb045 #1
Hardware name: Qualcomm SA8540P Ride (DT)
Workqueue: events_unbound async_run_entry_fn
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __request_module+0x1e0/0x460
lr : __request_module+0x1d8/0x460
sp : ffff800009323b90
x29: ffff800009323b90 x28: 0000000000000000 x27: 0000000000000000
x26: ffff800009323d50 x25: ffff7b9045f57810 x24: ffff7b9045f57830
x23: ffffdc5a83e426e8 x22: ffffdc5ae80a9818 x21: 0000000000000001
x20: ffffdc5ae7502f98 x19: ffff7b9045f57800 x18: ffffffffffffffff
x17: 312f716572667665 x16: 642f7366752e3030 x15: 0000000000000000
x14: 000000000000021c x13: 0000000000005400 x12: ffff7b9042ed7614
x11: ffff7b9042ed7600 x10: 00000000636c0890 x9 : 0000000000000038
x8 : ffff7b9045f2c880 x7 : ffff7b9045f57c68 x6 : 0000000000000080
x5 : 0000000000000000 x4 : 8000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : ffffdc5ae5d382f0 x0 : 0000000000000001
Call trace:
__request_module+0x1e0/0x460
try_then_request_governor+0x7c/0x100
devfreq_add_device+0x4b0/0x5fc
ufshcd_async_scan+0x1d4/0x310 [ufshcd_core]
async_run_entry_fn+0x34/0xe0
process_one_work+0x1d0/0x320
worker_thread+0x14c/0x444
kthread+0x10c/0x110
ret_from_fork+0x10/0x20
This occurs because synchronous module loading from async is not
allowed. According to __request_module():
/*
* We don't allow synchronous module loading from async. Module
* init may invoke async_synchronize_full() which will end up
* waiting for this task which already is waiting for the module
* loading to complete, leading to a deadlock.
*/
Such a deadlock was experienced on the Qualcomm QDrive3/sa8540p-ride. With
DEVFREQ_GOV_SIMPLE_ONDEMAND=m, the boot hangs after the warning.
Fix both the warning and the deadlock by moving devfreq initialization out
of the async routine.
Tested on the sa8540p-ride by using fio to put the UFS under load, and
printing the trace generated by
/sys/kernel/tracing/events/ufs/ufshcd_clk_scaling events. The trace looks
similar with and without the change.
Link: https://lore.kernel.org/r/20230217194423.42553-1-athierry@redhat.com
Signed-off-by: Adrien Thierry <athierry@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'include/ufs')
| -rw-r--r-- | include/ufs/ufshcd.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index ed9e3d5addb3..05e416414e41 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -978,6 +978,7 @@ struct ufs_hba { struct completion *uic_async_done; enum ufshcd_state ufshcd_state; + bool logical_unit_scan_finished; u32 eh_flags; u32 intr_mask; u16 ee_ctrl_mask; |