linux-toradex.git/drivers/s390/block/Kconfig, branch v5.0

dax: introduce CONFIG_DAX_DRIVER

2018-04-03T12:41:19+00:00

In support of allowing device-mapper to compile out idle/dead code when
there are no dax providers in the system, introduce the DAX_DRIVER
symbol. This is selected by all leaf drivers that device-mapper might be
layered on top. This allows device-mapper to conditionally 'select DAX'
only when a provider is present.

Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Reported-by: Bart Van Assche 
Reviewed-by: Mike Snitzer 
Signed-off-by: Dan Williams

dax: require 'struct page' by default for filesystem dax

2018-01-20T00:50:53+00:00

If a dax buffer from a device that does not map pages is passed to
read(2) or write(2) as a target for direct-I/O it triggers SIGBUS. If
gdb attempts to examine the contents of a dax buffer from a device that
does not map pages it triggers SIGBUS. If fork(2) is called on a process
with a dax mapping from a device that does not map pages it triggers
SIGBUS. 'struct page' is required otherwise several kernel code paths
break in surprising ways. Disable filesystem-dax on devices that do not
map pages.

In addition to needing pfn_to_page() to be valid we also require devmap
pages.  We need this to detect dax pages in the get_user_pages_fast()
path and so that we can stop managing the VM_MIXEDMAP flag. For DAX
drivers that have not supported get_user_pages() to date we allow them
to opt-in to supporting DAX with the CONFIG_FS_DAX_LIMITED configuration
option which requires ->direct_access() to return pfn_t_special() pfns.
This leaves DAX support in brd disabled and scheduled for removal.

Note that when the initial dax support was being merged a few years back
there was concern that struct page was unsuitable for use with next
generation persistent memory devices. The theoretical concern was that
struct page access, being such a hotly used data structure in the
kernel, would lead to media wear out. While that was a reasonable
conservative starting position it has not held true in practice. We have
long since committed to using devm_memremap_pages() to support higher
order kernel functionality that needs get_user_pages() and
pfn_to_page().


Cc: Jeff Moyer 
Cc: Ross Zwisler 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Reviewed-by: Jan Kara 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Gerald Schaefer 
Signed-off-by: Dan Williams

s390: add a few more SPDX identifiers

2017-12-05T06:51:09+00:00

Add the correct SPDX license to a few more files under arch/s390 and
drivers/s390 which have been missed to far.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

Signed-off-by: Martin Schwidefsky

s390/scm: remove cluster option

2017-06-12T14:25:55+00:00

Remove CONFIG_SCM_BLOCK_CLUSTER_WRITE and related code. This quirk is
no longer needed on current hardware.

Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

dcssblk: add dax_operations support

2017-04-19T22:14:36+00:00

Setup a dax_dev to have the same lifetime as the dcssblk block device
and add a ->direct_access() method that is equivalent to
dcssblk_direct_access(). Once fs/dax.c has been converted to use
dax_operations the old dcssblk_direct_access() will be removed.

Reported-by: Gerald Schaefer 
Acked-by: Gerald Schaefer 
Signed-off-by: Dan Williams

s390/scm_block: force cluster writes

2012-09-26T13:45:01+00:00

Force writes to Storage Class Memory (SCM) to be in done in clusters.

Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

s390: add scm block driver

2012-09-26T13:45:01+00:00

Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.

Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

[S390] cleanup s390 Kconfig

2011-01-05T11:47:23+00:00

Make use of def_bool and def_tristate where possible and add sensible
defaults to the config symbols where applicable. This shortens the
defconfig file by another ~40 lines.

Signed-off-by: Martin Schwidefsky

[S390] dasd: fix double elevator_exit call when deadline iosched fails to load

2008-04-17T05:46:55+00:00

I compiled the kernel without deadline, and the dasd code exits the old
scheduler (CFQ), fails to load the new one (deadline), and then things just
hang - with one of these (sorry about the weird chars - I copy & pasted it
from a 3270 console):

dasd(eckd): 0.0.0151: 3390/0A(CU:3990/01) Cyl:3338 Head:15 Sec:224
------------ cut here ------------
Badness at kernel/mutex.c:134
Modules linked in: dasd_eckd_mod dasd_mod
CPU: 0 Not tainted 2.6.25-rc3 #9
Process exe (pid: 538, task: 000000000d172000, ksp: 000000000d21ef88)
Krnl PSW : 0404000180000000 000000000022fb5c (mutex_lock_nested+0x2a4/0x2cc)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000024218 000000000076fc78 0000000000000000 000000000000000f
           000000000022f92e 0000000000449898 000000000f921c00 000003e000162590
           00000000001539c4 000000000d172000 070000007fffffff 000000000d21f400
           000000000f8f2560 00000000002413f8 000000000022fb44 000000000d21f400
Krnl Code: 000000000022fb50: bf2f1000           icm     %r2,15,0(%r1)
           000000000022fb54: a774fef6           brc     7,22f940
           000000000022fb58: a7f40001           brc     15,22fb5a
          >000000000022fb5c: a7f4fef2           brc     15,22f940
           000000000022fb60: c0e5fffa112a       brasl   %r14,171db4
           000000000022fb66: 1222               ltr     %r2,%r2
           000000000022fb68: a784fedb           brc     8,22f91e
           000000000022fb6c: c010002a0086       larl    %r1,76fc78
Call Trace:
(<000000000022f92e> mutex_lock_nested+0x76/0x2cc)
 <00000000001539c4> elevator_exit+0x38/0x80
 <0000000000156ffe> blk_cleanup_queue+0x62/0x7c
 <000003e0001d5414> dasd_change_state+0xe0/0x8ec
 <000003e0001d5cae> dasd_set_target_state+0x8e/0x9c
 <000003e0001d5f74> dasd_generic_set_online+0x160/0x284
 <000003e00011e83a> dasd_eckd_set_online+0x2e/0x40
 <0000000000199bf4> ccw_device_set_online+0x170/0x2c0
 <0000000000199d9e> online_store_recog_and_online+0x5a/0x14c
 <000000000019a08a> online_store+0xbe/0x2ec
 <000000000018456c> dev_attr_store+0x38/0x58
 <000000000010efbc> sysfs_write_file+0x130/0x190
 <00000000000af582> vfs_write+0xb2/0x160
 <00000000000afc7c> sys_write+0x54/0x9c
 <0000000000025e16> sys32_write+0x2e/0x50
 <0000000000024218> sysc_noemu+0x10/0x16
 <0000000077e82bd2> 0x77e82bd2

Set elevator pointer to NULL in order to avoid double elevator_exit
calls when elevator_init call for deadline iosched fails.
Also make sure the dasd device driver depends on IOSCHED_DEADLINE so
the default IO scheduler of the dasd driver is present.

Signed-off-by: Josef 'Jeff' Sipek 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens

[S390] Kconfig: use common Kconfig files for s390.

2007-05-10T13:46:08+00:00

Disband drivers/s390/Kconfig, use the common Kconfig files. The s390
specific config options from drivers/s390/Kconfig are moved to the
respective common Kconfig files.

Signed-off-by: Martin Schwidefsky