RE: [Linuxarm] Re: [PATCH for-next 00/32] spin lock usage optimization for SCSI drivers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, 9 Feb 2021, Song Bao Hua (Barry Song) wrote:

sonic_interrupt() uses an irq lock within an interrupt handler to 
avoid issues relating to this. This kind of locking may be needed in 
the drivers you are trying to patch. Or it might not. Apparently, 
no-one has looked.

Is the comment in sonic_interrupt() outdated according to this:
m68k: irq: Remove IRQF_DISABLED
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=77a4279
http://lkml.iu.edu/hypermail/linux/kernel/1109.2/01687.html


The removal of IRQF_DISABLED isn't relevant to this driver. Commit 
77a42796786c ("m68k: Remove deprecated IRQF_DISABLED") did not disable 
interrupts, it just removed some code to enable them.

The code and comments in sonic_interrupt() are correct. You can confirm 
this for yourself quite easily using QEMU and a cross-compiler.

and this:
genirq: Warn when handler enables interrupts
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b738a50a

wouldn't genirq report a warning on m68k?


There is no warning from m68k builds. That's because arch_irqs_disabled() 
returns true when the IPL is non-zero.


Thanks
Barry

Thanks
Barry





[Index of Archives]     [Video for Linux]     [Yosemite News]     [Linux S/390]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux