linux-sg2042/drivers
Luben Tuikov 24d720b726 [SCSI] Retrieve the Caching mode page
Some kernel transport drivers unconditionally disable
retrieval of the Caching mode page. One such for example is
the BBB/CBI transport over USB.  Such a restraint is too
harsh as some devices do support the Caching mode
page. Unconditionally enabling the retrieval of this mode
page over those transports at their transport code level may
result in some devices failing and becoming unusable.

This patch implements a method of retrieving the Caching
mode page without unconditionally enabling it in the
transports which unconditionally disable it. The idea is to
ask for all supported pages, page code 0x3F, and then search
for the Caching mode page in the mode parameter data
returned. The sd driver already asks for all the mode pages
supported by the attached device by setting the page code to
0x3F in order to find out if the media is write protected by
reading the WP bit in the Device Specific Parameter
field. It then attempts to retrieve only the Caching mode
page by setting the page code to 8 and actually attempting
to retrieve it if and only if the transport allows it.

The method implemented here is that if the transport doesn't
allow retrieval of the Caching mode page and the device is
not RBC, then we ask for all pages supported by setting the
page code to 0x3F (similarly to how the WP bit is retrieved
above), and then we search for the Caching mode page in the
mode parameter data returned.

With this patch, devices over SATA, report this (no change):

Oct 22 18:45:58 localhost kernel: sd 0:0:0:0: [sda] 976773168 512-byte logical blocks: (500 GB/465 GiB)
Oct 22 18:45:58 localhost kernel: sd 0:0:0:0: Attached scsi generic sg0 type 0
Oct 22 18:45:58 localhost kernel: sd 0:0:0:0: [sda] Write Protect is off
Oct 22 18:45:58 localhost kernel: sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
Oct 22 18:45:58 localhost kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

Smart devices report their Caching mode page. This is a
change where we'd previously see the kernel making
assumption about the device's cache being write-through:

Oct 22 18:45:58 localhost kernel: sd 6:0:0:0: Attached scsi generic sg2 type 0
Oct 22 18:45:58 localhost kernel: sd 6:0:0:0: [sdb] 610472646 4096-byte logical blocks: (2.50 TB/2.27 TiB)
Oct 22 18:45:58 localhost kernel: sd 6:0:0:0: [sdb] Write Protect is off
Oct 22 18:45:58 localhost kernel: sd 6:0:0:0: [sdb] Mode Sense: 47 00 10 08
Oct 22 18:45:58 localhost kernel: sd 6:0:0:0: [sdb] Write cache: enabled, read cache: enabled, supports DPO and FUA

And "dumb" devices over BBB, are correctly shown not to
support reporting the Caching mode page:

Oct 22 18:49:06 localhost kernel: sd 7:0:0:0: [sdc] 15663104 512-byte logical blocks: (8.01 GB/7.46 GiB)
Oct 22 18:49:06 localhost kernel: sd 7:0:0:0: [sdc] Write Protect is off
Oct 22 18:49:06 localhost kernel: sd 7:0:0:0: [sdc] Mode Sense: 23 00 00 00
Oct 22 18:49:06 localhost kernel: sd 7:0:0:0: [sdc] No Caching mode page present
Oct 22 18:49:06 localhost kernel: sd 7:0:0:0: [sdc] Assuming drive cache: write through

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2010-12-21 12:23:53 -06:00
..
accessibility
acpi Merge branch 'bugzilla-23002' into release 2010-12-13 22:40:54 -05:00
amba
ata sata_via: apply magic FIFO fix to vt6420 too 2010-11-19 13:16:26 -05:00
atm atm: correct sysfs 'device' link creation and parent relationships 2010-12-10 15:45:05 -08:00
auxdisplay
base PM: Allow devices to be removed during late suspend and early resume 2010-11-11 01:50:53 +01:00
block xen: Provide a variant of __RING_SIZE() that is an integer constant expression 2010-12-15 12:34:28 -08:00
bluetooth Bluetooth: Add new PID for Atheros 3011 2010-12-01 15:51:01 -02:00
cdrom cdrom: gdrom: ctrl_in/outX to __raw_read/writeX conversion. 2010-10-27 14:33:39 +09:00
char agp/intel: Fix wrong kunmap in i830_cleanup() 2010-12-05 10:40:17 +00:00
clocksource ARM: shmobile: remove sh_timer_config clk member 2010-10-31 10:40:39 -04:00
connector connector: add module alias 2010-12-10 12:27:49 -08:00
cpufreq [CPUFREQ] add sampling_down_factor tunable to improve ondemand performance 2010-10-22 11:44:47 -04:00
cpuidle
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2010-11-13 09:55:56 -08:00
dca
dio
dma Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx 2010-12-14 13:35:47 -08:00
edac amd64_edac: Fix interleaving check 2010-12-08 19:52:54 +01:00
eisa
firewire firewire: ohci: fix regression with Agere FW643 rev 06, disable MSI 2010-12-12 15:47:02 +01:00
firmware dmi: log board, system, and BIOS information 2010-10-27 18:03:05 -07:00
gpio cs5535-gpio: apply CS5536 errata workaround for GPIOs 2010-12-02 14:51:15 -08:00
gpu drm/radeon/kms: don't apply 7xx HDP flush workaround on AGP 2010-12-09 17:59:24 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2010-12-02 17:40:04 -08:00
hwmon Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging 2010-12-14 13:36:26 -08:00
i2c i2c_intel_mid: Fix slash in sysfs name 2010-12-14 18:46:01 -08:00
ide ide: clean up timed out request handling 2010-10-26 10:17:30 -07:00
idle intel_idle: recognize ARAT on WSM-EX 2010-12-02 01:19:32 -05:00
ieee802154
infiniband IB/uverbs: Handle large number of entries in poll CQ 2010-12-08 15:23:49 -08:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-12-08 06:34:02 -08:00
isdn isdn: icn: Fix stack corruption bug. 2010-11-24 11:19:05 -08:00
leds leds: fix up dependencies 2010-12-02 14:51:15 -08:00
lguest
macintosh leds: fix up dependencies 2010-12-02 14:51:15 -08:00
mca
md md: protect against NULL reference when waiting to start a raid10. 2010-12-09 17:02:14 +11:00
media Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-12-05 16:41:13 -08:00
memstick
message SCSI host lock push-down 2010-11-16 13:33:23 -08:00
mfd mfd: Fix a memory leak when unload mc13xxx-core module 2010-10-29 00:30:43 +02:00
misc drivers/misc/isl29020.c: remove incorrect kfree in isl29020_remove() 2010-11-25 06:50:47 +09:00
mmc mmc: sdhci: 8-bit bus width changes 2010-11-22 15:12:04 -05:00
mtd Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 2010-12-14 17:36:35 -08:00
net xen: Provide a variant of __RING_SIZE() that is an integer constant expression 2010-12-15 12:34:28 -08:00
nubus
of
oprofile Merge branches 'perf-fixes-for-linus' and 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-30 11:43:26 -07:00
parisc parisc: KittyHawk LCD fix 2010-12-04 11:18:25 -05:00
parport Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
pci Merge branch 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2010-11-25 07:42:03 +09:00
pcmcia ARM: 6456/1: Fix for building DEBUG with sa11xx_base.c as a module. 2010-12-04 12:47:48 +00:00
platform wmi: use memcmp instead of strncmp to compare GUIDs 2010-12-06 17:19:13 -05:00
pnp ACPI/PNP: avoid section mismatch warning 2010-12-11 02:01:47 -05:00
power power: Revert "power_supply: Mark twl4030_charger as broken" 2010-10-29 00:30:44 +02:00
pps
ps3
rapidio rapidio: use resource_size() 2010-11-12 07:55:30 -08:00
regulator regulator: tps6586x: correct register table 2010-12-09 09:23:43 +00:00
rtc Merge branches 'sh/rtc' and 'common/clkfwk' into sh/urgent 2010-11-10 18:15:44 +09:00
s390 [SCSI] zfcp: Issue FCP command without holding SCSI host_lock 2010-12-09 09:41:23 -06:00
sbus Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2010-10-25 08:19:14 -07:00
scsi [SCSI] Retrieve the Caching mode page 2010-12-21 12:23:53 -06:00
serial Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb 2010-12-14 14:35:04 -08:00
sfi
sh Merge branch 'common/clkfwk' into sh-fixes-for-linus 2010-11-19 16:43:23 +09:00
sn
spi dw_spi: Fix missing final read in some polling situations 2010-12-14 18:48:59 -08:00
ssb ssb: b43-pci-bridge: Add new vendor for BCM4318 2010-11-22 15:19:31 -05:00
staging Merge branch 'staging-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6 2010-12-02 12:59:11 -08:00
tc
telephony Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2010-10-22 10:52:56 -07:00
thermal
tty Merge branch 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2010-12-02 12:58:16 -08:00
uio uio: Change mail address of Hans J. Koch 2010-11-10 16:57:11 -08:00
usb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-14 17:33:40 -08:00
uwb UWB: Return UWB_RSV_ALLOC_NOT_FOUND rather than crashing on NULL dereference if kzalloc fails 2010-11-11 07:14:07 -08:00
vhost vhost: correctly set bits of dirty pages 2010-11-29 10:26:55 +02:00
video fbdev: Fix fb_find_nearest_mode refresh comparison 2010-12-14 18:03:49 +09:00
virtio virtio: fix format of sysfs driver/vendor files 2010-11-24 15:21:12 +10:30
vlynq
w1 w1: don't allow arbitrary users to remove w1 devices 2010-10-27 18:03:17 -07:00
watchdog watchdog: it8712f_wdt: add note to Kconfig 2010-12-02 14:10:32 +00:00
xen Merge branch '2.6.37-rc4-pvhvm-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm 2010-12-03 11:30:57 -08:00
zorro BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
Kconfig
Makefile TTY: create drivers/tty and move the tty core files there 2010-11-05 08:10:33 -07:00