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Martin K. Petersen 321da3dc1f scsi: sd: usb_storage: uas: Access media prior to querying device properties 
It has been observed that some USB/UAS devices return generic properties
hardcoded in firmware for mode pages for a period of time after a device
has been discovered. The reported properties are either garbage or they do
not accurately reflect the characteristics of the physical storage device
attached in the case of a bridge.

Prior to commit 1e029397d1 ("scsi: sd: Reorganize DIF/DIX code to
avoid calling revalidate twice") we would call revalidate several
times during device discovery. As a result, incorrect values would
eventually get replaced with ones accurately describing the attached
storage. When we did away with the redundant revalidate pass, several
cases were reported where devices reported nonsensical values or would
end up in write-protected state.

An initial attempt at addressing this issue involved introducing a
delayed second revalidate invocation. However, this approach still
left some devices reporting incorrect characteristics.

Tasos Sahanidis debugged the problem further and identified that
introducing a READ operation prior to MODE SENSE fixed the problem and that
it wasn't a timing issue. Issuing a READ appears to cause the devices to
update their state to reflect the actual properties of the storage
media. Device properties like vendor, model, and storage capacity appear to
be correctly reported from the get-go. It is unclear why these devices
defer populating the remaining characteristics.

Match the behavior of a well known commercial operating system and
trigger a READ operation prior to querying device characteristics to
force the device to populate the mode pages.

The additional READ is triggered by a flag set in the USB storage and
UAS drivers. We avoid issuing the READ for other transport classes
since some storage devices identify Linux through our particular
discovery command sequence.

Link: https://lore.kernel.org/r/20240213143306.2194237-1-martin.petersen@oracle.com
Fixes: 1e029397d1 ("scsi: sd: Reorganize DIF/DIX code to avoid calling revalidate twice")
Cc: stable@vger.kernel.org
Reported-by: Tasos Sahanidis <tasos@tasossah.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Tasos Sahanidis <tasos@tasossah.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2024-02-14 12:46:47 -05:00
arch powerpc fixes for 6.8 #2 2024-01-21 11:04:29 -08:00
block for-6.8/block-2024-01-18 2024-01-18 18:22:40 -08:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: scomp - fix req->dst buffer overflow 2023-12-29 11:25:56 +08:00
Documentation Updates for time and clocksources: 2024-01-21 11:14:40 -08:00
drivers scsi: sd: usb_storage: uas: Access media prior to querying device properties 2024-02-14 12:46:47 -05:00
fs More bcachefs updates for 6.7-rc1 2024-01-21 14:01:12 -08:00
include scsi: sd: usb_storage: uas: Access media prior to querying device properties 2024-02-14 12:46:47 -05:00
init Driver core changes for 6.8-rc1 2024-01-18 09:48:40 -08:00
io_uring for-6.8/io_uring-2024-01-18 2024-01-18 18:17:57 -08:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel Updates for time and clocksources: 2024-01-21 11:14:40 -08:00
lib RISC-V Patches for the 6.8 Merge Window, Part 4 2024-01-20 11:06:04 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
net Assorted CephFS fixes and cleanups with nothing standing out. 2024-01-19 09:58:55 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples RISC-V Patches for the 6.8 Merge Window, Part 4 2024-01-20 11:06:04 -08:00
scripts Coccinelle change for v6.8 2024-01-20 14:20:34 -08:00
security + Features 2024-01-19 10:53:55 -08:00
sound sound fixes for 6.8-rc1 2024-01-19 12:30:29 -08:00
tools RISC-V Patches for the 6.8 Merge Window, Part 4 2024-01-20 11:06:04 -08:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch '6.8/scsi-staging' into 6.8/scsi-fixes 2024-01-22 15:49:29 -05:00
Makefile Linux 6.8-rc1 2024-01-21 14:11:32 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.