-----Original Message-----
From: Finn Thain [mailto:fthain@telegraphics.com.au]
Sent: Monday, February 8, 2021 8:57 PM
To: tanxiaofei <redacted>
Cc: jejb@linux.ibm.com; martin.petersen@oracle.com;
linux-scsi@vger.kernel.org; linux-kernel@vger.kernel.org;
linuxarm@openeuler.org
Subject: [Linuxarm] Re: [PATCH for-next 00/32] spin lock usage optimization
for SCSI drivers

On Sun, 7 Feb 2021, Xiaofei Tan wrote:

quoted

Replace spin_lock_irqsave with spin_lock in hard IRQ of SCSI drivers.
There are no function changes, but may speed up if interrupt happen too
often.

This change doesn't necessarily work on platforms that support nested
interrupts.

Were you able to measure any benefit from this change on some other
platform?

I think the code disabling irq in hardIRQ is simply wrong.
Since this commit
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e58aa3d2d0cc
genirq: Run irq handlers with interrupts disabled

interrupt handlers are definitely running in a irq-disabled context
unless irq handlers enable them explicitly in the handler to permit
other interrupts.

Please see also,
https://lore.kernel.org/linux-scsi/89c5cb05cb844939ae684db0077f675f@h3c.co
m/
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Thanks
Barry