Re: [PATCH v1] scsi: Don't select SCSI_PROC_FS by default

[Douglas Gilbert]

On 2019-07-05 3:22 a.m., Hannes Reinecke wrote:
> On 6/18/19 7:43 PM, Elliott, Robert (Servers) wrote:
> > > -----Original Message-----
> > > From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Bart
> > > Van Assche
> > > Sent: Monday, June 17, 2019 10:28 PM
> > > To: dgilbert@xxxxxxxxxxxx; Marc Gonzalez <marc.w.gonzalez@xxxxxxx>; James Bottomley
> > > <jejb@xxxxxxxxxxxxx>; Martin Petersen <martin.petersen@xxxxxxxxxx>
> > > Cc: SCSI <linux-scsi@xxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>; Christoph Hellwig
> > > <hch@xxxxxx>
> > > Subject: Re: [PATCH v1] scsi: Don't select SCSI_PROC_FS by default
> > >
> > > On 6/17/19 5:35 PM, Douglas Gilbert wrote:
> > > > For sg3_utils:
> > > >
> > > > $ find . -name '*.c' -exec grep "/proc/scsi" {} \; -print
> > > > static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > > > ./src/sg_read.c
> > > > static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > > > ./src/sgp_dd.c
> > > > static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > > > ./src/sgm_dd.c
> > > > static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > > > ./src/sg_dd.c
> > > >   ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ "'echo 1 > /proc/scsi/sg/allow_dio'\n", q_len,
> > > > dirio_count);
> > > > ./testing/sg_tst_bidi.c
> > > > static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > > > ./examples/sgq_dd.c
> > > >
> > > > That is 6 (not 38) by my count.
> > >
> > > Hi Doug,
> > >
> > > This is the command I ran:
> > >
> > > $ git grep /proc/scsi | wc -l
> > > 38
> > >
> > > I think your query excludes scripts/rescan-scsi-bus.sh.
> > >
> > > Bart.
> >
> > Here's the full list to ensure the discussion doesn't overlook anything:
> >
> > sg3_utils-1.44$ grep -R /proc/scsi .
> > ./src/sg_read.c:static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > ./src/sgp_dd.c:static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > ./src/sgm_dd.c:static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > ./src/sg_dd.c:static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > ./scripts/rescan-scsi-bus.sh:# Return hosts. /proc/scsi/HOSTADAPTER/? must exist
> > ./scripts/rescan-scsi-bus.sh:  for driverdir in /proc/scsi/*; do
> > ./scripts/rescan-scsi-bus.sh:    driver=${driverdir#/proc/scsi/}
> > ./scripts/rescan-scsi-bus.sh:      name=${hostdir#/proc/scsi/*/}
> > ./scripts/rescan-scsi-bus.sh:# Get /proc/scsi/scsi info for device $host:$channel:$id:$lun
> > ./scripts/rescan-scsi-bus.sh:    SCSISTR=$(grep -A "$LN" -e "$grepstr" /proc/scsi/scsi)
> > ./scripts/rescan-scsi-bus.sh:    DRV=`grep 'Attached drivers:' /proc/scsi/scsi 2>/dev/null`
> > ./scripts/rescan-scsi-bus.sh:      echo "scsi report-devs 1" >/proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:      DRV=`grep 'Attached drivers:' /proc/scsi/scsi 2>/dev/null`
> > ./scripts/rescan-scsi-bus.sh:      echo "scsi report-devs 0" >/proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:# Outputs description from /proc/scsi/scsi (unless arg passed)
> > ./scripts/rescan-scsi-bus.sh:        echo "scsi remove-single-device $devnr" > /proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:          echo "scsi add-single-device $devnr" > /proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:      echo "scsi add-single-device $devnr" > /proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:      echo "scsi add-single-device $devnr" > /proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:      echo "scsi add-single-device $host $channel $id $SCAN_WILD_CARD" > /proc/scsi/scsi
> > ./scripts/rescan-scsi-bus.sh:if test ! -d /sys/class/scsi_host/ -a ! -d /proc/scsi/; then
> > ./ChangeLog:    /proc/scsi/sg/allow_dio is '0'
> > ./ChangeLog:  - change sg_debug to call system("cat /proc/scsi/sg/debug");
> > ./suse/sg3_utils.changes:  * Support systems without /proc/scsi
> > ./examples/sgq_dd.c:static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";
> > ./doc/sg_read.8:If direct IO is selected and /proc/scsi/sg/allow_dio
> > ./doc/sg_read.8:"echo 1 > /proc/scsi/sg/allow_dio". An alternate way to avoid the
> > ./doc/sg_map.8:observing the output of the command: "cat /proc/scsi/scsi".
> > ./doc/sgp_dd.8:at completion. If direct IO is selected and /proc/scsi/sg/allow_dio
> > ./doc/sgp_dd.8:this at completion. If direct IO is selected and /proc/scsi/sg/allow_dio
> > ./doc/sgp_dd.8:mapping to SCSI block devices should be checked with 'cat /proc/scsi/scsi'
> > ./doc/sg_dd.8:notes this at completion. If direct IO is selected and /proc/scsi/sg/allow_dio
> > ./doc/sg_dd.8:this at completion. If direct IO is selected and /proc/scsi/sg/allow_dio
> > ./doc/sg_dd.8:with 'echo 1 > /proc/scsi/sg/allow_dio'.
> > ./doc/sg_dd.8:mapping to SCSI block devices should be checked with 'cat /proc/scsi/scsi',
> As mentioned, rescan-scsi-bus.sh is keeping references to /proc/scsi as
> a fall back only, as it's meant to work kernel independent. Per default
> it'll be using /sys, and will happily work without /proc/scsi.
>
> So it's really only /proc/scsi/sg which carries some meaningful
> information; maybe we should move/copy it to somewhere else.
>
> I personally like getting rid of /proc/scsi.

/proc/scsi/device_info doesn't seem to be in sysfs.

Could the contents of /proc/scsi/sg/* be placed in
/sys/class/scsi_generic/* ? Currently that directory only has symlinks
to the sg devices.

Doug Gilbert