RE: [PATCH 2.6.12-rc4-mm1 3/4] megaraid_sas: updating the driver

From: Salyzyn, Mark (mark_salyzyn_at_adaptec.com)
Date: 05/24/05

  • Next message: Clifford T. Matthews: "surprisingly slow accept/connect cycle time" 
    Date:	Tue, 24 May 2005 16:45:05 -0400
To: "James Bottomley" <James.Bottomley@SteelEye.com>, "Arjan van de Ven" <arjan@infradead.org>

    James Bottomley writes:
    > On Mon, 2005-05-16 at 10:06 +0200, Arjan van de Ven wrote:
    >> > + spin_lock( instance->host_lock );
    >> > + cmd->scmd->scsi_done( cmd->scmd );
    >> > + spin_unlock( instance->host_lock );
    >>
    >> are you really sure you don't want to use spin_lock_irqsave() here ?
    >
    >Actually, don't bother with the lock at all. scsi_done() is designed
    to
    >be called locklessly.

    Could I get an historical (2.4 & Distribution) perspective on this. At
    which point, or what code/include/manifest/version delineating it, would
    you say the driver is no longer, if ever, required to place a lock
    (host_lock or io_request_lock) around the scsi_done call?

    I expect (or hope) the answer to be: always needs io_request_lock in
    2.4, never needed the host_lock in 2.5+.

    -- Mark Salyzyn
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  • Next message: Clifford T. Matthews: "surprisingly slow accept/connect cycle time"

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