When we have DMA QMAN with multiple streams, we need to know whether the
command buffer contains at least one DMA packet in order to configure the
barriers correctly when adding the 2xMSG_PROT at the end of the JOB. If
there is no DMA packet, then there is no need to put engine barrier. This
is relevant only for GAUDI as GOYA doesn't have streams so the engine can't
be busy by another stream.
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Retrieve from the firmware the DMA mask value we need to set according to
the device's PCI controller configuration. This is needed when working on
POWER9 machines, as the device's PCI controller is configured in a
different way in those machines.
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Add comments for the various errors and states of the firmware during boot.
Add a mapping of a new register that will tell the driver whether the
firmware executed the request from the driver or if it has encountered an
error.
Add a new enum for the possible values of this register.
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
When doing training, the DL framework (e.g. tensorflow) performs hundreds
of thousands of memory allocations and mappings. In case the driver needs
to perform hard-reset during training, the driver kills the application and
unmaps all those memory allocations. Unfortunately, because of that large
amount of mappings, the driver isn't able to do that in the current timeout
(5 seconds). Therefore, increase the timeout significantly to 30 seconds
to avoid situation where the driver resets the device with active mappings,
which sometime can cause a kernel bug.
BTW, it doesn't mean we will spend all the 30 seconds because the reset
thread checks every one second if the unmap operation is done.
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
When the system administrator asks the driver to soft or hard reset the
device through sysfs, the driver should display a warning in the kernel log
to explain why it suddenly resets the device.
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Move the code of device CPU initialization from being ASIC-Dependent to
common code. In addition, add support for the new error reporting feature
of the firmware boot code.
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
We want to remove the following restrictions/assumptions in our driver:
1. The H/W queue index is also the completion queue index.
2. The H/W queue index is also the IRQ number of the completion queue.
3. All queues of the same type have consecutive indexes.
Therefore we add the support for H/W queues of the same type with
nonconsecutive indexes and completion queue index and IRQ number different
than the H/W queue index.
Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Stop-on-error mode in DMA is useful as it stops the transaction
immediately upon error e.g. page fault.
But it may cause the next command submission to fail as is leaves the DMA
in unstable state.
Therefore we remove the stop-on-error configuration from the DMA.
Stop-on-err is still available for debug.
Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Upon reset of the ASIC, the driver would have waited for the CPU to come
out of reset before finishing the reset process. This was done for the
purpose of making the CPU available to answer FLR requests. However, when a
VM shuts down, the driver isn't removed so a reset never happens.
Therefore, remove this waiting period as we don't need it.
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Adding bulk read support:
Sending a 'trigger' command in the dedicated sysfs entry of bus master
device send a conversion command for all the slaves on the bus. The sysfs
entry is added as soon as at least one device supporting this feature
is detected on the bus.
The behavior of the sysfs reading temperature on the device is as follow:
* If no bulk read pending, trigger a conversion on the device, wait for
the conversion to be done, read the temperature in device RAM
* If a bulk read has been trigger, access directly the device RAM
This behavior is the same on the 2 sysfs entries ('temperature' and
'w1_slave').
Reading the therm_bulk_read sysfs give the status of bulk operations:
* '-1': conversion in progress on at least 1 sensor
* '1': conversion complete but at least one sensor has not been read yet
* '0': no bulk operation. Reading temperature on ecah device will trigger
a conversion
As not all devices support bulk read feature, it has been added in device
family structure.
The attribute is set at master level as soon as a supporting device is
discover. It is removed when the last supported device leave the bus.
The count of supported device is kept with the static counter
bulk_read_device_counter.
A strong pull up is apply on the line if at least one device required it.
The duration of the pull up is the max time required by a device on the
line, which depends on the resolution settings of each device. The strong
pull up could be adjust with the a module parameter.
Updating documentation in Documentation/ABI/testing/sysfs-driver-w1_therm
and Documentation/w1/slaves/w1_therm.rst accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203820.411483-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding device alarms settings by a dedicated sysfs entry alarms (RW):
read or write TH and TL in the device RAM. Checking devices in alarm
state could be performed using the master search command.
As alarms temperature level are store in a 8 bit register on the device
and are signed values, a safe cast shall be performed using the min and
max temperature that device are able to measure. This is done by
int_to_short inline function.
A 'write_data' field is added in the device structure, to bind the
correct writing function, as some devices may have 2 or 3 bytes RAM.
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203801.411253-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Optimizing temperature reading by reducing waiting conversion time
according to device resolution settings, as per device specification.
This is device dependent as not all the devices supports resolution
setting, so it has been added in device family structures.
The process to read the temperature on the device has been adapted in a
new function 'convert_t()', which replace the former 'read_therm()', is
introduce to deal with this timing. Strong pull up is also applied during
the required time, according to device power status needs and
'strong_pullup' module parameter.
'temperature_from_RAM()' function is introduced to get the correct
temperature computation (device dependent) from device RAM data.
An new sysfs entry has been added to ouptut only temperature. The old
entry w1_slave has been kept for compatibility, without changing its
output format.
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203742.411039-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver implement 2 hardware functions to access device RAM:
* copy_scratchpad
* recall_scratchpad
They act according to device specifications.
As EEPROM operations are not device dependent (all w1_therm can perform
EEPROM read/write operation following the same protocol), it is removed
from device families structures.
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203725.410844-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding resolution sysfs entry (RW) to get or set the device resolution
Write values are managed as follow:
* '9..12': resolution to set in bit
* Anything else: do nothing
Read values are :
* '9..12': device resolution in bit
* '-xx': xx is kernel error when reading the resolution
Only supported devices will show the sysfs entry. A new family has been
created for DS18S20 devices as they do not implement resolution feature.
The resolution of each device is check when the device is
discover by the bus master, in 'w1_therm_add_slave(struct w1_slave *)'.
The status is stored in the device structure w1_therm_family_data so
that the driver always knows the resolution of each device, which could
be used later to determine the required conversion duration (resolution
dependent).
The resolution is re evaluate each time a user read or write the sysfs
entry.
To avoid looping through the w1_therm_families at run time, the pointer
'specific_functions' is set up to the correct 'w1_therm_family_converter'
when the slave is added (which mean when it is discovered by the master).
This initialization is done by a helper function
'device_family(struct w1_slave *sl)', and a dedicated macro
'SLAVE_SPECIFIC_FUNC(sl)' allow the access to the specific function of the
slave device.
'read_scratchpad' and 'write_scratchpad' are the hardware functions to
access the device RAM, as per protocol specification.
It cancel the former 'precision' functions, which was only set and never
read (so not stored in the device struct).
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203708.410649-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding ext_power sysfs entry (RO). Return the power status of the device:
- 0: device parasite powered
- 1: device externally powered
- xx: xx is kernel error
The power status of each device is check when the device is
discover by the bus master, in 'w1_therm_add_slave(struct w1_slave *)'.
The status is stored in the device structure w1_therm_family_data so
that the driver always knows the power state of each device, which could
be used later to determine the required strong pull up to apply on the
line.
The power status is re evaluate each time the sysfs ext_power read by
a user.
The hardware function 'read_powermode(struct w1_slave *sl)' act just as
per device specifications, sending W1_READ_PSUPPLY command on the bus,
and issue a read time slot, reading only one bit.
A helper function 'bool bus_mutex_lock(struct mutex *lock)' is introduced.
It try to aquire the bus mutex several times (W1_THERM_MAX_TRY), waiting
W1_THERM_RETRY_DELAY between two attempt.
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203650.410439-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix reset_select_slave issue during devices discovery by the master on
bus. The w1_reset_select_slave() from w1_io.c, which was previously used,
assume that if the slave count is 1 there is only one slave attached on
the bus. This is not always true. For example when discovering devices,
when the first device is discover by the bus master, its slave count is
1, but some other slaves may be on the bus.
In that case instead of adressing command to the attached slave the
master throw a SKIP ROM command so that all slaves attached on the bus
will answer simultenaously causing data collision.
A dedicated reset_select_slave() function is implemented here,
it always perform an adressing to each slave using the MATCH ROM
command.
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203610.409975-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding code comments to split code in dedicated parts. After the global
declarations (defines, macros and function declarations), code is organized
as follow :
- Device and family dependent structures and functions
- Interfaces functions
- Helpers functions
- Hardware functions
- Sysfs interface functions
Signed-off-by: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203535.409599-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 2a127da461 ("nvmem: add support for the write-protect pin")
added support for handling write-protect pins to the nvmem core, and
Commit 1c89074bf8 ("eeprom: at24: remove the write-protect pin support")
retrofitted the at24 driver to use this support.
These changes broke write() on the nvmem sysfs attribute for eeproms
which utilize a write-protect pin, as the write callback invokes the
nvmem device's reg_write callback directly which no longer handles
changing the state of the write-protect pin.
Change the read and write callbacks for the sysfs attribute to invoke
nvmme_reg_read/nvmem_reg_write helpers which handle this, rather than
calling reg_read/reg_write directly.
Fixes: 2a127da461 ("nvmem: add support for the write-protect pin")
Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200511145042.31223-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Moritz writes:
FPGA Manager changes for 5.8
Here's the first set of changes for the 5.8-rc1 merge window.
Dominic's change adds support for accessing AFU regions with gdb.
Gustavo's change is a cleanup patch regarding variable lenght arrays.
Richard's changes update dt-bindings and add support for stratix and agilex.
Sergiu's changes update spi transfers with the new delay field.
Xu's change addresses an issue with a wrong return value.
Shubhrajyoti's change makes the Zynq FPGA driver return -EPROBE_DEFER on
check of devm_clk_get failure.
Xu's change for DFL enables multiple opens.
All of these patches have been reviewed, have appropriate Acked-by's and
have been in the last few linux-next releases without issues.
Signed-off-by: Moritz Fischer <mdf@kernel.org>
* tag 'fpga-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mdf/linux-fpga:
fpga: dfl: afu: support debug access to memory-mapped afu regions
fpga: dfl.h: Replace zero-length array with flexible-array member
arm64: dts: agilex: correct service layer driver's compatible value
dt-bindings, firmware: add compatible value Intel Stratix10 service layer binding
fpga: stratix10-soc: add compatible property value for intel agilex
arm64: dts: agilex: correct FPGA manager driver's compatible value
dt-bindings: fpga: add compatible value to Stratix10 SoC FPGA manager binding
fpga: machxo2-spi: Use new structure for SPI transfer delays
fpga: ice40-spi: Use new structure for SPI transfer delays
fpga: dfl: support multiple opens on feature device node.
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507185318.GA14393@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull x86 fixes from Thomas Gleixner:
"A set of fixes for x86:
- Ensure that direct mapping alias is always flushed when changing
page attributes. The optimization for small ranges failed to do so
when the virtual address was in the vmalloc or module space.
- Unbreak the trace event registration for syscalls without arguments
caused by the refactoring of the SYSCALL_DEFINE0() macro.
- Move the printk in the TSC deadline timer code to a place where it
is guaranteed to only be called once during boot and cannot be
rearmed by clearing warn_once after boot. If it's invoked post boot
then lockdep rightfully complains about a potential deadlock as the
calling context is different.
- A series of fixes for objtool and the ORC unwinder addressing
variety of small issues:
- Stack offset tracking for indirect CFAs in objtool ignored
subsequent pushs and pops
- Repair the unwind hints in the register clearing entry ASM code
- Make the unwinding in the low level exit to usermode code stop
after switching to the trampoline stack. The unwind hint is no
longer valid and the ORC unwinder emits a warning as it can't
find the registers anymore.
- Fix unwind hints in switch_to_asm() and rewind_stack_do_exit()
which caused objtool to generate bogus ORC data.
- Prevent unwinder warnings when dumping the stack of a
non-current task as there is no way to be sure about the
validity because the dumped stack can be a moving target.
- Make the ORC unwinder behave the same way as the frame pointer
unwinder when dumping an inactive tasks stack and do not skip
the first frame.
- Prevent ORC unwinding before ORC data has been initialized
- Immediately terminate unwinding when a unknown ORC entry type
is found.
- Prevent premature stop of the unwinder caused by IRET frames.
- Fix another infinite loop in objtool caused by a negative
offset which was not catched.
- Address a few build warnings in the ORC unwinder and add
missing static/ro_after_init annotations"
* tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/unwind/orc: Move ORC sorting variables under !CONFIG_MODULES
x86/apic: Move TSC deadline timer debug printk
ftrace/x86: Fix trace event registration for syscalls without arguments
x86/mm/cpa: Flush direct map alias during cpa
objtool: Fix infinite loop in for_offset_range()
x86/unwind/orc: Fix premature unwind stoppage due to IRET frames
x86/unwind/orc: Fix error path for bad ORC entry type
x86/unwind/orc: Prevent unwinding before ORC initialization
x86/unwind/orc: Don't skip the first frame for inactive tasks
x86/unwind: Prevent false warnings for non-current tasks
x86/unwind/orc: Convert global variables to static
x86/entry/64: Fix unwind hints in rewind_stack_do_exit()
x86/entry/64: Fix unwind hints in __switch_to_asm()
x86/entry/64: Fix unwind hints in kernel exit path
x86/entry/64: Fix unwind hints in register clearing code
objtool: Fix stack offset tracking for indirect CFAs
Pull objtool fix from Thomas Gleixner:
"A single fix for objtool to prevent an infinite loop in the
jump table search which can be triggered when building the
kernel with '-ffunction-sections'"
* tag 'objtool-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix infinite loop in find_jump_table()
Pull locking fix from Thomas Gleixner:
"A single fix for the fallout of the recent futex uacess rework.
With those changes GCC9 fails to analyze arch_futex_atomic_op_inuser()
correctly and emits a 'maybe unitialized' warning. While we usually
ignore compiler stupidity the conditional store is pointless anyway
because the correct case has to store. For the fault case the extra
store does no harm"
* tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ARM: futex: Address build warning
Pull iommu fixes from Joerg Roedel:
- Race condition fixes for the AMD IOMMU driver.
These are five patches fixing two race conditions around
increase_address_space(). The first race condition was around the
non-atomic update of the domain page-table root pointer and the
variable containing the page-table depth (called mode). This is fixed
now be merging page-table root and mode into one 64-bit field which
is read/written atomically.
The second race condition was around updating the page-table root
pointer and making it public before the hardware caches were flushed.
This could cause addresses to be mapped and returned to drivers which
are not reachable by IOMMU hardware yet, causing IO page-faults. This
is fixed too by adding the necessary flushes before a new page-table
root is published.
Related to the race condition fixes these patches also add a missing
domain_flush_complete() barrier to update_domain() and a fix to bail
out of the loop which tries to increase the address space when the
call to increase_address_space() fails.
Qian was able to trigger the race conditions under high load and
memory pressure within a few days of testing. He confirmed that he
has seen no issues anymore with the fixes included here.
- Fix for a list-handling bug in the VirtIO IOMMU driver.
* tag 'iommu-fixes-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/virtio: Reverse arguments to list_add
iommu/amd: Do not flush Device Table in iommu_map_page()
iommu/amd: Update Device Table in increase_address_space()
iommu/amd: Call domain_flush_complete() in update_domain()
iommu/amd: Do not loop forever when trying to increase address space
iommu/amd: Fix race in increase_address_space()/fetch_pte()
Pull block fixes from Jens Axboe:
- a small series fixing a use-after-free of bdi name (Christoph,Yufen)
- NVMe fix for a regression with the smaller CQ update (Alexey)
- NVMe fix for a hang at namespace scanning error recovery (Sagi)
- fix race with blk-iocost iocg->abs_vdebt updates (Tejun)
* tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block:
nvme: fix possible hang when ns scanning fails during error recovery
nvme-pci: fix "slimmer CQ head update"
bdi: add a ->dev_name field to struct backing_dev_info
bdi: use bdi_dev_name() to get device name
bdi: move bdi_dev_name out of line
vboxsf: don't use the source name in the bdi name
iocost: protect iocg->abs_vdebt with iocg->waitq.lock
It seems that for whatever reason, gcc-10 ends up not inlining a couple
of functions that used to be inlined before. Even if they only have one
single callsite - it looks like gcc may have decided that the code was
unlikely, and not worth inlining.
The code generation difference is harmless, but caused a few new section
mismatch errors, since the (now no longer inlined) function wasn't in
the __init section, but called other init functions:
Section mismatch in reference from the function kexec_free_initrd() to the function .init.text:free_initrd_mem()
Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memremap()
Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memunmap()
So add the appropriate __init annotation to make modpost not complain.
In both cases there were trivially just a single callsite from another
__init function.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull RISC-V fixes from Palmer Dabbelt:
"A smattering of fixes and cleanups:
- Dead code removal.
- Exporting riscv_cpuid_to_hartid_mask for modules.
- Per-CPU tracking of ISA features.
- Setting max_pfn correctly when probing memory.
- Adding a note to the VDSO so glibc can check the kernel's version
without a uname().
- A fix to force the bootloader to initialize the boot spin tables,
which still get used as a fallback when SBI-0.1 is enabled"
* tag 'riscv-for-linus-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: Remove unused code from STRICT_KERNEL_RWX
riscv: force __cpu_up_ variables to put in data section
riscv: add Linux note to vdso
riscv: set max_pfn to the PFN of the last page
RISC-V: Remove N-extension related defines
RISC-V: Add bitmap reprensenting ISA features common across CPUs
RISC-V: Export riscv_cpuid_to_hartid_mask() API
gcc-10 has started warning about conflicting types for a few new
built-in functions, particularly 'free()'.
This results in warnings like:
crypto/xts.c:325:13: warning: conflicting types for built-in function ‘free’; expected ‘void(void *)’ [-Wbuiltin-declaration-mismatch]
because the crypto layer had its local freeing functions called
'free()'.
Gcc-10 is in the wrong here, since that function is marked 'static', and
thus there is no chance of confusion with any standard library function
namespace.
But the simplest thing to do is to just use a different name here, and
avoid this gcc mis-feature.
[ Side note: gcc knowing about 'free()' is in itself not the
mis-feature: the semantics of 'free()' are special enough that a
compiler can validly do special things when seeing it.
So the mis-feature here is that gcc thinks that 'free()' is some
restricted name, and you can't shadow it as a local static function.
Making the special 'free()' semantics be a function attribute rather
than tied to the name would be the much better model ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc-10 now warns about passing aliasing pointers to functions that take
restricted pointers.
That's actually a great warning, and if we ever start using 'restrict'
in the kernel, it might be quite useful. But right now we don't, and it
turns out that the only thing this warns about is an idiom where we have
declared a few functions to be "printf-like" (which seems to make gcc
pick up the restricted pointer thing), and then we print to the same
buffer that we also use as an input.
And people do that as an odd concatenation pattern, with code like this:
#define sysfs_show_gen_prop(buffer, fmt, ...) \
snprintf(buffer, PAGE_SIZE, "%s"fmt, buffer, __VA_ARGS__)
where we have 'buffer' as both the destination of the final result, and
as the initial argument.
Yes, it's a bit questionable. And outside of the kernel, people do have
standard declarations like
int snprintf( char *restrict buffer, size_t bufsz,
const char *restrict format, ... );
where that output buffer is marked as a restrict pointer that cannot
alias with any other arguments.
But in the context of the kernel, that 'use snprintf() to concatenate to
the end result' does work, and the pattern shows up in multiple places.
And we have not marked our own version of snprintf() as taking restrict
pointers, so the warning is incorrect for now, and gcc picks it up on
its own.
If we do start using 'restrict' in the kernel (and it might be a good
idea if people find places where it matters), we'll need to figure out
how to avoid this issue for snprintf and friends. But in the meantime,
this warning is not useful.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the final array bounds warning removal for gcc-10 for now.
Again, the warning is good, and we should re-enable all these warnings
when we have converted all the legacy array declaration cases to
flexible arrays. But in the meantime, it's just noise.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the controller is reconnecting, the host fails I/O and admin
commands as the host cannot reach the controller. ns scanning may
revalidate namespaces during that period and it is wrong to remove
namespaces due to these failures as we may hang (see 205da24343).
One command that may fail is nvme_identify_ns_descs. Since we return
success due to having ns identify descriptor list optional, we continue
to compare ns identifiers in nvme_revalidate_disk, obviously fail and
return -ENODEV to nvme_validate_ns, which will remove the namespace.
Exactly what we don't want to happen.
Fixes: 22802bf742 ("nvme: Namepace identification descriptor list is optional")
Tested-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pre-incrementing ->cq_head can't be done in memory because OOB value
can be observed by another context.
This devalues space savings compared to original code :-\
$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-32 (-32)
Function old new delta
nvme_poll_irqdisable 464 456 -8
nvme_poll 455 447 -8
nvme_irq 388 380 -8
nvme_dev_disable 955 947 -8
But the code is minimal now: one read for head, one read for q_depth,
one increment, one comparison, single instruction phase bit update and
one write for new head.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: John Garry <john.garry@huawei.com>
Tested-by: John Garry <john.garry@huawei.com>
Fixes: e2a366a4b0 ("nvme-pci: slimmer CQ head update")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cache a copy of the name for the life time of the backing_dev_info
structure so that we can reference it even after unregistering.
Fixes: 68f23b8906 ("memcg: fix a crash in wb_workfn when a device disappears")
Reported-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
