Date: Mon, 11 Aug 1997 21:10:01 -0700 (PDT) From: "Justin T. Gibbs" <gibbs@plutotech.com> To: freebsd-bugs Subject: Re: kern/4270: ch driver does not use bounce buffers Message-ID: <199708120410.VAA26399@hub.freebsd.org>
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The following reply was made to PR kern/4270; it has been noted by GNATS. From: "Justin T. Gibbs" <gibbs@plutotech.com> To: fmc@reanimators.org Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: kern/4270: ch driver does not use bounce buffers Date: Mon, 11 Aug 1997 22:03:28 -0600 > Some notes: ... > (c) There's another code path in the ch driver where a buffer > is allocated on the stack (not malloc()ed) and passed > down through scsi_scsi_cmd(). Is that safe? I don't > know. (See ch_get_params() and the use of sense_data.) Yes, it happens to be safe as scsi_scsi_cmd has a hack in it to detect stack allocations and to bounce them either through a malloced buffer or a vm_bounce buffer. It is a hack since the type drivers should not be putting anything on the stack since at the time the virtual address is translated/accessed/etc. you may be in a totally different process context or none at all. -- Justin T. Gibbs =========================================== FreeBSD: Turning PCs into workstations ===========================================
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