igc: Fix BUG: scheduling while atomic

Replace usleep_range() method with udelay() method to allow atomic contexts
in low-level MDIO access functions.

The following issue can be seen by doing the following:
$ modprobe -r bonding
$ modprobe -v bonding max_bonds=1 mode=1 miimon=100 use_carrier=0
$ ip link set bond0 up
$ ifenslave bond0 eth0 eth1

[  982.357308] BUG: scheduling while atomic: kworker/u64:0/9/0x00000002
[  982.364431] INFO: lockdep is turned off.
[  982.368824] Modules linked in: bonding sctp ip6_udp_tunnel udp_tunnel mlx4_ib ib_uverbs ib_core mlx4_en mlx4_core nfp tls sunrpc intel_rapl_msr iTCO_wdt iTCO_vendor_support mxm_wmi dcdbas intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel rapl intel_cstate intel_uncore pcspkr lpc_ich mei_me ipmi_ssif mei ipmi_si ipmi_devintf ipmi_msghandler wmi acpi_power_meter xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg mgag200 drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci crc32c_intel libata i2c_algo_bit tg3 megaraid_sas igc dm_mirror dm_region_hash dm_log dm_mod [last unloaded: bonding]
[  982.437941] CPU: 25 PID: 9 Comm: kworker/u64:0 Kdump: loaded Tainted: G        W        --------- -  - 4.18.0-348.el8.x86_64+debug #1
[  982.451333] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 2.7.0 12/005/2017
[  982.459791] Workqueue: bond0 bond_mii_monitor [bonding]
[  982.465622] Call Trace:
[  982.468355]  dump_stack+0x8e/0xd0
[  982.472056]  __schedule_bug.cold.60+0x3a/0x60
[  982.476919]  __schedule+0x147b/0x1bc0
[  982.481007]  ? firmware_map_remove+0x16b/0x16b
[  982.485967]  ? hrtimer_fixup_init+0x40/0x40
[  982.490625]  schedule+0xd9/0x250
[  982.494227]  schedule_hrtimeout_range_clock+0x10d/0x2c0
[  982.500058]  ? hrtimer_nanosleep_restart+0x130/0x130
[  982.505598]  ? hrtimer_init_sleeper_on_stack+0x90/0x90
[  982.511332]  ? usleep_range+0x88/0x130
[  982.515514]  ? recalibrate_cpu_khz+0x10/0x10
[  982.520279]  ? ktime_get+0xab/0x1c0
[  982.524175]  ? usleep_range+0x88/0x130
[  982.528355]  usleep_range+0xdd/0x130
[  982.532344]  ? console_conditional_schedule+0x30/0x30
[  982.537987]  ? igc_put_hw_semaphore+0x17/0x60 [igc]
[  982.543432]  igc_read_phy_reg_gpy+0x111/0x2b0 [igc]
[  982.548887]  igc_phy_has_link+0xfa/0x260 [igc]
[  982.553847]  ? igc_get_phy_id+0x210/0x210 [igc]
[  982.558894]  ? lock_acquire+0x34d/0x890
[  982.563187]  ? lock_downgrade+0x710/0x710
[  982.567659]  ? rcu_read_unlock+0x50/0x50
[  982.572039]  igc_check_for_copper_link+0x106/0x210 [igc]
[  982.577970]  ? igc_config_fc_after_link_up+0x840/0x840 [igc]
[  982.584286]  ? rcu_read_unlock+0x50/0x50
[  982.588661]  ? lock_release+0x591/0xb80
[  982.592939]  ? lock_release+0x591/0xb80
[  982.597220]  igc_has_link+0x113/0x330 [igc]
[  982.601887]  ? lock_downgrade+0x710/0x710
[  982.606362]  igc_ethtool_get_link+0x6d/0x90 [igc]
[  982.611614]  bond_check_dev_link+0x131/0x2c0 [bonding]
[  982.617350]  ? bond_time_in_interval+0xd0/0xd0 [bonding]
[  982.623277]  ? rcu_read_lock_held+0x62/0xc0
[  982.627944]  ? rcu_read_lock_sched_held+0xe0/0xe0
[  982.633198]  bond_mii_monitor+0x314/0x2500 [bonding]
[  982.638738]  ? lock_contended+0x880/0x880
[  982.643214]  ? bond_miimon_link_change+0xa0/0xa0 [bonding]
[  982.649336]  ? lock_acquire+0x34d/0x890
[  982.653615]  ? lock_downgrade+0x710/0x710
[  982.658089]  ? debug_object_deactivate+0x221/0x340
[  982.663436]  ? rcu_read_unlock+0x50/0x50
[  982.667811]  ? debug_print_object+0x2b0/0x2b0
[  982.672672]  ? __switch_to_asm+0x41/0x70
[  982.677049]  ? __switch_to_asm+0x35/0x70
[  982.681426]  ? _raw_spin_unlock_irq+0x24/0x40
[  982.686288]  ? trace_hardirqs_on+0x20/0x195
[  982.690956]  ? _raw_spin_unlock_irq+0x24/0x40
[  982.695818]  process_one_work+0x8f0/0x1770
[  982.700390]  ? pwq_dec_nr_in_flight+0x320/0x320
[  982.705443]  ? debug_show_held_locks+0x50/0x50
[  982.710403]  worker_thread+0x87/0xb40
[  982.714489]  ? process_one_work+0x1770/0x1770
[  982.719349]  kthread+0x344/0x410
[  982.722950]  ? kthread_insert_work_sanity_check+0xd0/0xd0
[  982.728975]  ret_from_fork+0x3a/0x50

Fixes: 5586838f ("igc: Add code for PHY support")
Reported-by: Corinna Vinschen <vinschen@redhat.com>
Suggested-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Corinna Vinschen <vinschen@redhat.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/igc/igc_phy.c

@@ -581,7 +581,7 @@ static s32 igc_read_phy_reg_mdic(struct igc_hw *hw, u32 offset, u16 *data)
 	 * the lower time out
 	 */
 	for (i = 0; i < IGC_GEN_POLL_TIMEOUT; i++) {
-		usleep_range(500, 1000);
+		udelay(50);
 		mdic = rd32(IGC_MDIC);
 		if (mdic & IGC_MDIC_READY)
 			break;
@@ -638,7 +638,7 @@ static s32 igc_write_phy_reg_mdic(struct igc_hw *hw, u32 offset, u16 data)
 	 * the lower time out
 	 */
 	for (i = 0; i < IGC_GEN_POLL_TIMEOUT; i++) {
-		usleep_range(500, 1000);
+		udelay(50);
 		mdic = rd32(IGC_MDIC);
 		if (mdic & IGC_MDIC_READY)
 			break;