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authorStephen M. Cameron <scameron@beardog.cce.hp.com>2011-11-16 09:21:49 +0100
committerJens Axboe <axboe@kernel.dk>2011-11-16 09:21:49 +0100
commit0007a4c90a11a5371c8b3f80b220fa402a399189 (patch)
tree3fb4a0158f87f539b2415fad35e958d1d1259910 /Documentation
parent7035b5df3c071ccaf2f1694b96bd8958b0eb37ca (diff)
downloadvexpress-lsk-0007a4c90a11a5371c8b3f80b220fa402a399189.tar.gz
cciss: auto engage SCSI mid layer at driver load time
A long time ago, probably in 2002, one of the distros, or maybe more than one, loaded block drivers prior to loading the SCSI mid layer. This meant that the cciss driver, being a block driver, could not engage the SCSI mid layer at init time without panicking, and relied on being poked by a userland program after the system was up (and the SCSI mid layer was therefore present) to engage the SCSI mid layer. This is no longer the case, and cciss can safely rely on the SCSI mid layer being present at init time and engage the SCSI mid layer straight away. This means that users will see their tape drives and medium changers at driver load time without need for a script in /etc/rc.d that does this: for x in /proc/driver/cciss/cciss* do echo "engage scsi" > $x done However, if no tape drives or medium changers are detected, the SCSI mid layer will not be engaged. If a tape drive or medium change is later hot-added to the system it will then be necessary to use the above script or similar for the device(s) to be acceesible. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/blockdev/cciss.txt14
1 files changed, 6 insertions, 8 deletions
diff --git a/Documentation/blockdev/cciss.txt b/Documentation/blockdev/cciss.txt
index 71464e09ec1..b79d0a13e7c 100644
--- a/Documentation/blockdev/cciss.txt
+++ b/Documentation/blockdev/cciss.txt
@@ -98,14 +98,12 @@ You must enable "SCSI tape drive support for Smart Array 5xxx" and
"SCSI support" in your kernel configuration to be able to use SCSI
tape drives with your Smart Array 5xxx controller.
-Additionally, note that the driver will not engage the SCSI core at init
-time. The driver must be directed to dynamically engage the SCSI core via
-the /proc filesystem entry which the "block" side of the driver creates as
-/proc/driver/cciss/cciss* at runtime. This is because at driver init time,
-the SCSI core may not yet be initialized (because the driver is a block
-driver) and attempting to register it with the SCSI core in such a case
-would cause a hang. This is best done via an initialization script
-(typically in /etc/init.d, but could vary depending on distribution).
+Additionally, note that the driver will engage the SCSI core at init
+time if any tape drives or medium changers are detected. The driver may
+also be directed to dynamically engage the SCSI core via the /proc filesystem
+entry which the "block" side of the driver creates as
+/proc/driver/cciss/cciss* at runtime. This is best done via a script.
+
For example:
for x in /proc/driver/cciss/cciss[0-9]*