Date: Wed, 22 Feb 2012 23:21:36 +0530 From: "Desai, Kashyap" <Kashyap.Desai@lsi.com> To: "freebsd-scsi@freebsd.org" <freebsd-scsi@freebsd.org>, freebsd-stable <freebsd-stable@freebsd.org>, "ed@FreeBSD.org" <ed@FreeBSD.org>, "joerg@FreeBSD.org" <joerg@FreeBSD.org> Cc: "Justin T. Gibbs" <gibbs@freebsd.org>, "Kenneth D. Merry" <ken@freebsd.org>, "McConnell, Stephen" <Stephen.McConnell@lsi.com> Subject: RE: mpslsi0 : Trying sleep, but thread marked as sleeping prohibited Message-ID: <B2FD678A64EAAD45B089B123FDFC3ED72B96D3484A@inbmail01.lsi.com>
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Adding Ed Schouten and Jorg Wunsch as I see there are author of msleep/mtx= related APIs. > -----Original Message----- > From: Desai, Kashyap > Sent: Wednesday, February 22, 2012 7:37 PM > To: freebsd-scsi@freebsd.org; freebsd-stable > Cc: 'Kenneth D. Merry'; McConnell, Stephen; Justin T. Gibbs > Subject: mpslsi0 : Trying sleep, but thread marked as sleeping > prohibited >=20 > Hi, >=20 > I am doing some code changes in mps dirver. While working on those > changes, I come to know about something which is new to me. > Some expert help is required to clarify my doubt. >=20 > 1. When any irq is register with FreeBSD OS, it sets " TDP_NOSLEEPING" > pflag. It means though irq in freebsd is treated as thread, > We cannot sleep in IRQ because of " "TDP_NOSLEEPING " set. > 2. In mps driver we have below code snippet in ISR routine. >=20 >=20 > mps_dprint(sc, MPS_TRACE, "%s\n", __func__); > mps_lock(sc); > mps_intr_locked(data); > mps_unlock(sc); >=20 > I wonder why there is no issue with above code ? Theoretical we cannot > sleep in ISR. (as explained in #1) > Any thoughts ? >=20 >=20 > 3. I recently added few place msleep() instead of DELAY in ISR context > and I see > " Trying sleep, but thread marked as sleeping prohibited". >=20 >=20 > ` Kashyap
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