No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Benjamin Block 1749ef00f7 scsi: core: replace GFP_ATOMIC with GFP_KERNEL in scsi_scan.c
We had a test-report where, under memory pressure, adding LUNs to the
systems would fail (the tests add LUNs strictly in sequence):

[ 5525.853432] scsi 0:0:1:1088045124: Direct-Access     IBM      2107900          .148 PQ: 0 ANSI: 5
[ 5525.853826] scsi 0:0:1:1088045124: alua: supports implicit TPGS
[ 5525.853830] scsi 0:0:1:1088045124: alua: device naa.6005076303ffd32700000000000044da port group 0 rel port 43
[ 5525.853931] sd 0:0:1:1088045124: Attached scsi generic sg10 type 0
[ 5525.854075] sd 0:0:1:1088045124: [sdk] Disabling DIF Type 1 protection
[ 5525.855495] sd 0:0:1:1088045124: [sdk] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB)
[ 5525.855606] sd 0:0:1:1088045124: [sdk] Write Protect is off
[ 5525.855609] sd 0:0:1:1088045124: [sdk] Mode Sense: ed 00 00 08
[ 5525.855795] sd 0:0:1:1088045124: [sdk] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 5525.857838]  sdk: sdk1
[ 5525.859468] sd 0:0:1:1088045124: [sdk] Attached SCSI disk
[ 5525.865073] sd 0:0:1:1088045124: alua: transition timeout set to 60 seconds
[ 5525.865078] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA
[ 5526.015070] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA
[ 5526.015213] sd 0:0:1:1088045124: alua: port group 00 state A preferred supports tolusnA
[ 5526.587439] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured
[ 5526.588562] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured

Looking at the code of scsi_alloc_sdev(), and all the calling contexts,
there seems to be no reason to use GFP_ATMOIC here. All the different
call-contexts use a mutex at some point, and nothing in between that
requires no sleeping, as far as I could see. Additionally, the code that
later allocates the block queue for the device (scsi_mq_alloc_queue())
already uses GFP_KERNEL.

There are similar allocations in two other functions:
scsi_probe_and_add_lun(), and scsi_add_lun(),; that can also be done with
GFP_KERNEL.

Here is the contexts for the three functions so far:

    scsi_alloc_sdev()
        scsi_probe_and_add_lun()
            scsi_sequential_lun_scan()
                __scsi_scan_target()
                    scsi_scan_target()
                        mutex_lock()
                    scsi_scan_channel()
                        scsi_scan_host_selected()
                            mutex_lock()
            scsi_report_lun_scan()
                __scsi_scan_target()
    	            ...
            __scsi_add_device()
                mutex_lock()
            __scsi_scan_target()
                ...
        scsi_report_lun_scan()
            ...
        scsi_get_host_dev()
            mutex_lock()

    scsi_probe_and_add_lun()
        ...

    scsi_add_lun()
        scsi_probe_and_add_lun()
            ...

So replace all these, and give them a bit of a better chance to succeed,
with more chances of reclaim.

Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-02-27 09:39:28 -05:00
arch Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
block scsi: block: remove bidi support 2019-02-05 21:30:27 -05:00
certs
crypto
Documentation scsi: ufs-bsg: Allow reading descriptors 2019-02-27 09:00:02 -05:00
drivers scsi: core: replace GFP_ATOMIC with GFP_KERNEL in scsi_scan.c 2019-02-27 09:39:28 -05:00
firmware
fs scsi: fs: remove exofs 2019-02-05 21:28:13 -05:00
include scsi: kill command serial number 2019-02-27 09:19:24 -05:00
init
ipc
kernel Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
lib Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
LICENSES
mm
net
samples
scripts
security
sound
tools Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS scsi: MAINTAINERS: SCSI initiator and target tweaks 2019-02-26 10:07:29 -05:00
Makefile Linux 5.0-rc1 2019-01-06 17:08:20 -08:00
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.