queuecommand called in IRQ run level

queuecommand called in IRQ run level

[Rabeeh Khoury]

Hi All,

Is it possible that queuecommand be called in ISR time ? (IRQ run level)
I want to do kmalloc with GFP_KERNEL priority in queuecommand (or 
actually pci_pool_alloc which eventually will call kmalloc in pool 
getting low in memory).

Thank you,
Rabeeh

Re: queuecommand called in IRQ run level

[Alan Cox]

On Sul, 2003-08-24 at 18:46, Rabeeh Khoury wrote:
> Hi All,
> 
> Is it possible that queuecommand be called in ISR time ? (IRQ run level)
> I want to do kmalloc with GFP_KERNEL priority in queuecommand (or 
> actually pci_pool_alloc which eventually will call kmalloc in pool 
> getting low in memory).

You cannot use GFP_KERNEL in this situation - it may block, it may cause
further I/O. 

Re: queuecommand called in IRQ run level

[Martin Peschke3]

It's better to avoid any schedule in queuecommand.
First, the io_request_lock is held (irqsave) when your queuecommand
routine is called. Second, queuecommand is called from scsi_request_fn,
which is usually executed when completed SCSI command are processed,
which is done in a bottom half.
This applies to 2.4, and I suspect 2.6 is similar in that regard.

Martin

Rabeeh Khoury <rabeeh@il.marvell.com>@vger.kernel.org on 24/08/2003
19:46:02

Sent by:    linux-scsi-owner@vger.kernel.org


To:    linux-scsi@vger.kernel.org
cc:
Subject:    queuecommand called in IRQ run level


Hi All,

Is it possible that queuecommand be called in ISR time ? (IRQ run level)
I want to do kmalloc with GFP_KERNEL priority in queuecommand (or
actually pci_pool_alloc which eventually will call kmalloc in pool
getting low in memory).

Thank you,
Rabeeh


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