hwtracing: hisi_ptt: Fix potential sleep in atomic context

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7BZYX


CVE: NA

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From: Yicong Yang <yangyicong@hisilicon.com>

We're using pci_irq_vector() to obtain the interrupt number and then
bind it to the CPU start perf under the protection of spinlock in
pmu::start(). pci_irq_vector() might sleep since [1] because it will
call msi_domain_get_virq() to get the MSI interrupt number and it
needs to acquire dev->msi.data->mutex. Getting a mutex will sleep on
contention. So use pci_irq_vector() in an atomic context is problematic.

This patch cached the interrupt number in the probe() and uses the
cached data instead to avoid potential sleep.

[1] commit 82ff8e6b ("PCI/MSI: Use msi_get_virq() in pci_get_vector()")
Fixes: ff0de066 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>