s390/cio: sort out physical vs virtual pointers usage

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.

Use virt_to_phys() for intparm interrupt param

s390/cio: sort out physical vs virtual pointers usage

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.

Use virt_to_phys() for intparm interrupt parameter to
convert a 64-bit virtual address to the 32-bit physical
address, which is expected to be below 2GB.

Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

show more ...

s390/cio: remove uevent suppress from cio driver

commit fa1a8c23eb7d ("s390: cio: Delay uevents for subchannels")
introduced suppression of uevents for a subchannel until after it is
clear that the

s390/cio: remove uevent suppress from cio driver

commit fa1a8c23eb7d ("s390: cio: Delay uevents for subchannels")
introduced suppression of uevents for a subchannel until after it is
clear that the subchannel would not be unregistered again
immediately. This was done to avoid uevents being generated for I/O
subchannels with no valid device, which can happen on LPAR.

However, this also has some drawbacks: All subchannel drivers need to
manually remove the uevent suppression and generate an ADD uevent as
soon as they are sure that the subchannel will stay around. This misses
out on all uevents that are not the initial ADD uevent that would be
generated while uevents are suppressed; for example, all subchannels
were missing the BIND uevent.

As uevents being generated even for I/O subchannels without an
operational device turned out to be not as bad as missing uevents and
complicating the code flow, let's remove uevent suppression for
subchannels.

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
[cohuck@redhat.com: modified changelog]
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Link: https://lore.kernel.org/r/20211122103756.352463-2-vneethv@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

show more ...

s390/cio: Make struct css_driver::remove return void

The driver core ignores the return value of css_remove()
(because there is only little it can do when a device disappears) and
all callbacks retu

s390/cio: Make struct css_driver::remove return void

The driver core ignores the return value of css_remove()
(because there is only little it can do when a device disappears) and
all callbacks return 0 anyhow.

So make it impossible for future drivers to return an unused error code
by changing the remove prototype to return void.

The real motivation for this change is the quest to make struct
bus_type::remove return void, too.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

s390/cio: remove pm support from chsc subchannel driver

As part of removing the broken pm-support from s390 arch, remove
the pm-calls from chsc subchannel driver. The power-management
functions are

s390/cio: remove pm support from chsc subchannel driver

As part of removing the broken pm-support from s390 arch, remove
the pm-calls from chsc subchannel driver. The power-management
functions are unused since the 'commit 394216275c7d ("s390: remove
broken hibernate / power management support")'.

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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driver_find_device: Unify the match function with class_find_device()

The driver_find_device() accepts a match function pointer to
filter the devices for lookup, similar to bus/class_find_device().

driver_find_device: Unify the match function with class_find_device()

The driver_find_device() accepts a match function pointer to
filter the devices for lookup, similar to bus/class_find_device().
However, there is a minor difference in the prototype for the
match parameter for driver_find_device() with the now unified
version accepted by {bus/class}_find_device(), where it doesn't
accept a "const" qualifier for the data argument. This prevents
us from reusing the generic match functions for driver_find_device().

For this reason, change the prototype of the driver_find_device() to
make the "match" parameter in line with {bus/class}_find_device()
and adjust its callers to use the const qualifier. Also, we could
now promote the "data" parameter to const as we pass it down
as a const parameter to the match functions.

Cc: Corey Minyard <minyard@acm.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Cc: Shyam Sundar S K <shyam-sundar.s-k@amd.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

compat: Move compat_timespec/ timeval to compat_time.h

All the current architecture specific defines for these
are the same. Refactor these common defines to a common
header file.

The new common li

compat: Move compat_timespec/ timeval to compat_time.h

All the current architecture specific defines for these
are the same. Refactor these common defines to a common
header file.

The new common linux/compat_time.h is also useful as it
will eventually be used to hold all the defines that
are needed for compat time types that support non y2038
safe types. New architectures need not have to define these
new types as they will only use new y2038 safe syscalls.
This file can be deleted after y2038 when we stop supporting
non y2038 safe syscalls.

The patch also requires an operation similar to:

git grep "asm/compat\.h" | cut -d ":" -f 1 | xargs -n 1 sed -i -e "s%asm/compat.h%linux/compat.h%g"

Cc: acme@kernel.org
Cc: benh@kernel.crashing.org
Cc: borntraeger@de.ibm.com
Cc: catalin.marinas@arm.com
Cc: cmetcalf@mellanox.com
Cc: cohuck@redhat.com
Cc: davem@davemloft.net
Cc: deller@gmx.de
Cc: devel@driverdev.osuosl.org
Cc: gerald.schaefer@de.ibm.com
Cc: gregkh@linuxfoundation.org
Cc: heiko.carstens@de.ibm.com
Cc: hoeppner@linux.vnet.ibm.com
Cc: hpa@zytor.com
Cc: jejb@parisc-linux.org
Cc: jwi@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: mark.rutland@arm.com
Cc: mingo@redhat.com
Cc: mpe@ellerman.id.au
Cc: oberpar@linux.vnet.ibm.com
Cc: oprofile-list@lists.sf.net
Cc: paulus@samba.org
Cc: peterz@infradead.org
Cc: ralf@linux-mips.org
Cc: rostedt@goodmis.org
Cc: rric@kernel.org
Cc: schwidefsky@de.ibm.com
Cc: sebott@linux.vnet.ibm.com
Cc: sparclinux@vger.kernel.org
Cc: sth@linux.vnet.ibm.com
Cc: ubraun@linux.vnet.ibm.com
Cc: will.deacon@arm.com
Cc: x86@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: James Hogan <jhogan@kernel.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

show more ...

s390: cio: add SPDX identifiers to the remaining files

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/s390/cio/

s390: cio: add SPDX identifiers to the remaining files

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/s390/cio/ files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/debug: improve debug_event

debug_event currently truncates the data if used with a size larger than
the buf_size of the debug feature. For lots of callers of this function,
wrappers have been i

s390/debug: improve debug_event

debug_event currently truncates the data if used with a size larger than
the buf_size of the debug feature. For lots of callers of this function,
wrappers have been implemented that loop until all data is handled.

Move that functionality into debug_event_common and get rid of the wrappers.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/chsc: fix ioctl CHSC_INFO_CU command

Via CHSC_INFO_CU we ought to provide userspace with control unit
configuration data. Due to an erroneous request code we trigger the
wrong chsc command. Fix

s390/chsc: fix ioctl CHSC_INFO_CU command

Via CHSC_INFO_CU we ought to provide userspace with control unit
configuration data. Due to an erroneous request code we trigger the
wrong chsc command. Fix this copy and paste error.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/cio: Remove unused inline assemblies

There is no longer a need to maintain two versions of the same inline
assembly - one with exception handling, and one without - so get rid of
the duplicates

s390/cio: Remove unused inline assemblies

There is no longer a need to maintain two versions of the same inline
assembly - one with exception handling, and one without - so get rid of
the duplicates and adjust names accordingly. This applies to stsch_err
and msch_err which are now renamed to stsch and msch respectively,
while the original msch function is removed.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390: Delete unnecessary checks before the function call "debug_unregister"

The debug_unregister() function performs also input parameter validation.
Thus the test around the calls is not needed.

T

s390: Delete unnecessary checks before the function call "debug_unregister"

The debug_unregister() function performs also input parameter validation.
Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390: cio driver &__get_cpu_var replacements

Use this_cpu_ptr() instead of &__get_cpu_var()

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

s390/lowcore: replace lowcore irb array with a per-cpu variable

Remove the 96-byte irb array from the lowcore and create a per-cpu
variable instead. That way we will pick up any change in the defini

s390/lowcore: replace lowcore irb array with a per-cpu variable

Remove the 96-byte irb array from the lowcore and create a per-cpu
variable instead. That way we will pick up any change in the definition
of the struct irb automatically.

Acked-By: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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s390: improve debug feature usage

The maximum usable buffer size of the s390 debug feature (when using
the sprintf_view) is 11 * sizeof(long) (1 pointer for the format
string + 10 arguments). When a

s390: improve debug feature usage

The maximum usable buffer size of the s390 debug feature (when using
the sprintf_view) is 11 * sizeof(long) (1 pointer for the format
string + 10 arguments). When a larger buffer size is specified the
additional memory is unused and wasted per debug entry. So reducing
the buffer size to its maximum (or to the actual buffer size used)
will make more precious debug feature space usable.

For pci_msg, chsc_msg, and cio_crw we use the additional usable dbf
space to reduce the number of allocated pages.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/chsc: Use snprintf instead of sprintf

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/cio: Introduce on-close CHSC IOCTLs

Introduce two new ioctls CHSC_ON_CLOSE_SET and CHSC_ON_CLOSE_REMOVE
that allow to add and remove one CHSC that is unconditionally executed
when the CHSC devi

s390/cio: Introduce on-close CHSC IOCTLs

Introduce two new ioctls CHSC_ON_CLOSE_SET and CHSC_ON_CLOSE_REMOVE
that allow to add and remove one CHSC that is unconditionally executed
when the CHSC device node is closed.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/cio: Make /dev/chsc a single-open device

In order to allow serialization of dynamic I/O with this patch
the /dev/chsc character device can only be accessed by one
single opener. Any subsequent

s390/cio: Make /dev/chsc a single-open device

In order to allow serialization of dynamic I/O with this patch
the /dev/chsc character device can only be accessed by one
single opener. Any subsequent open calls are rejected with EBUSY.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/cio: Introduce generic synchronous CHSC IOCTL

This patch adds a new ioctl CHSC_START_SYNC that allows to
execute any synchronous CHSC that is provided by user space.

Signed-off-by: Michael Hol

s390/cio: Introduce generic synchronous CHSC IOCTL

This patch adds a new ioctl CHSC_START_SYNC that allows to
execute any synchronous CHSC that is provided by user space.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

s390/irq: remove split irq fields from /proc/stat

Now that irq sum accounting for /proc/stat's "intr" line works again we
have the oddity that the sum field (first field) contains only the sum
of th

s390/irq: remove split irq fields from /proc/stat

Now that irq sum accounting for /proc/stat's "intr" line works again we
have the oddity that the sum field (first field) contains only the sum
of the second (external irqs) and third field (I/O interrupts).
The reason for that is that these two fields are already sums of all other
fields. So if we would sum up everything we would count every interrupt
twice.
This is broken since the split interrupt accounting was merged two years
ago: 052ff461c8427629aee887ccc27478fc7373237c "[S390] irq: have detailed
statistics for interrupt types".
To fix this remove the split interrupt fields from /proc/stat's "intr"
line again and only have them in /proc/interrupts.

This restores the old behaviour, seems to be the only sane fix and mimics
a behaviour from other architectures where /proc/interrupts also contains
more than /proc/stat's "intr" line does.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

compat: fix compile breakage on s390

The new is_compat_task() define for the !COMPAT case in
include/linux/compat.h conflicts with a similar define in
arch/s390/include/asm/compat.h.

This is the mi

compat: fix compile breakage on s390

The new is_compat_task() define for the !COMPAT case in
include/linux/compat.h conflicts with a similar define in
arch/s390/include/asm/compat.h.

This is the minimal patch which fixes the build issues.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

[S390] chsc_sch: add support for irq statistics

Add support for CHSC I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Sch

[S390] chsc_sch: add support for irq statistics

Add support for CHSC I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

[S390] css_driver: remove duplicate members

Remove the owner and name members of struct
css_driver and convert all drivers to store
this data in the embedded struct device_driver.

Signed-off-by: Se

[S390] css_driver: remove duplicate members

Remove the owner and name members of struct
css_driver and convert all drivers to store
this data in the embedded struct device_driver.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

[S390] css: move chsc_private to drv_data

Use the subchannels drv_data to access chsc_private
for chsc subchannels.

Note: Also set the drv_data prior to the cio_enable_subchannel
call, since we can

[S390] css: move chsc_private to drv_data

Use the subchannels drv_data to access chsc_private
for chsc subchannels.

Note: Also set the drv_data prior to the cio_enable_subchannel
call, since we can receive an interrupt the moment we enable
the subchannel and the IRQ handler relies on this data.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

[S390] chsc: use the global page to determine the chp desriptor

chsc_determine_channel_path_desc is called by a wrapper
who allocates a response struct. The response data
is then memcpy'ed to this r

[S390] chsc: use the global page to determine the chp desriptor

chsc_determine_channel_path_desc is called by a wrapper
who allocates a response struct. The response data
is then memcpy'ed to this response struct by
chsc_determine_channel_path_desc.

Change chsc_determine_base_channel_path_desc to use the
global chsc_page and deliver it to the function doing
the actual chsc call. The channel path desriptor is
then directly read from the response data.

As a result we get rid of the additional allocation
for the response struct.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

show more ...

llseek: automatically add .llseek fop

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three

llseek: automatically add .llseek fop

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>

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