* [PATCH v5 4/9] driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
2026-04-06 23:22 ` [PATCH v5 0/9] driver core: Fix some race conditions Douglas Anderson
@ 2026-04-06 23:22 ` Douglas Anderson
2026-04-06 23:23 ` [PATCH v5 9/9] driver core: Replace dev->offline + ->offline_disabled with accessors Douglas Anderson
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Douglas Anderson @ 2026-04-06 23:22 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich, Alan Stern
Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet,
Leon Romanovsky, Christoph Hellwig, Robin Murphy, maz,
Alexander Lobakin, Saravana Kannan, Douglas Anderson,
Andrew Morton, Jason Gunthorpe, driver-core, iommu, linux-kernel,
linux-mm, m.szyprowski
In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_skip_sync" over to the "flags"
field so modifications are safe.
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).
NOTE: even though previously we only took up a bit if
CONFIG_DMA_NEED_SYNC, in this change I reserve the bit
unconditionally. While we could get the "dynamic" behavior by changing
the flags definition to be an unnumbered "enum", Greg has requested
that the numbers be stable.
(no changes since v4)
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- New
include/linux/device.h | 8 ++++----
include/linux/dma-map-ops.h | 4 ++--
include/linux/dma-mapping.h | 2 +-
kernel/dma/mapping.c | 8 ++++----
mm/hmm.c | 2 +-
5 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/include/linux/device.h b/include/linux/device.h
index 620306e8380a..c38593cf2583 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -471,11 +471,14 @@ struct device_physical_location {
* until other devices probe successfully.
* @DEV_FLAG_DMA_IOMMU: Device is using default IOMMU implementation for DMA and
* doesn't rely on dma_ops structure.
+ * @DEV_FLAG_DMA_SKIP_SYNC: DMA sync operations can be skipped for coherent
+ * buffers.
*/
enum struct_device_flags {
DEV_FLAG_READY_TO_PROBE = 0,
DEV_FLAG_CAN_MATCH = 1,
DEV_FLAG_DMA_IOMMU = 2,
+ DEV_FLAG_DMA_SKIP_SYNC = 3,
DEV_FLAG_COUNT
};
@@ -569,7 +572,6 @@ enum struct_device_flags {
* and optionall (if the coherent mask is large enough) also
* for dma allocations. This flag is managed by the dma ops
* instance from ->dma_supported.
- * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers.
* @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
*
* At the lowest level, every device in a Linux system is represented by an
@@ -686,9 +688,6 @@ struct device {
#ifdef CONFIG_DMA_OPS_BYPASS
bool dma_ops_bypass : 1;
#endif
-#ifdef CONFIG_DMA_NEED_SYNC
- bool dma_skip_sync:1;
-#endif
DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
};
@@ -718,6 +717,7 @@ static inline bool dev_test_and_set_##accessor_name(struct device *dev) \
__create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
__create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
__create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
+__create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
#undef __create_dev_flag_accessors
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 60b63756df82..edd7de60a957 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -245,8 +245,8 @@ static inline void dma_reset_need_sync(struct device *dev)
{
#ifdef CONFIG_DMA_NEED_SYNC
/* Reset it only once so that the function can be called on hotpath */
- if (unlikely(dev->dma_skip_sync))
- dev->dma_skip_sync = false;
+ if (unlikely(dev_dma_skip_sync(dev)))
+ dev_clear_dma_skip_sync(dev);
#endif
}
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 99ef042ecdb4..ef4feb2b37d8 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -419,7 +419,7 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr);
static inline bool dma_dev_need_sync(const struct device *dev)
{
/* Always call DMA sync operations when debugging is enabled */
- return !dev->dma_skip_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG);
+ return !dev_dma_skip_sync(dev) || IS_ENABLED(CONFIG_DMA_API_DEBUG);
}
static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 6d3dd0bd3a88..76fc65d1a8a4 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -467,7 +467,7 @@ bool dma_need_unmap(struct device *dev)
{
if (!dma_map_direct(dev, get_dma_ops(dev)))
return true;
- if (!dev->dma_skip_sync)
+ if (!dev_dma_skip_sync(dev))
return true;
return IS_ENABLED(CONFIG_DMA_API_DEBUG);
}
@@ -483,16 +483,16 @@ static void dma_setup_need_sync(struct device *dev)
* mapping, if any. During the device initialization, it's
* enough to check only for the DMA coherence.
*/
- dev->dma_skip_sync = dev_is_dma_coherent(dev);
+ dev_assign_dma_skip_sync(dev, dev_is_dma_coherent(dev));
else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu &&
!ops->sync_sg_for_device && !ops->sync_sg_for_cpu)
/*
* Synchronization is not possible when none of DMA sync ops
* is set.
*/
- dev->dma_skip_sync = true;
+ dev_set_dma_skip_sync(dev);
else
- dev->dma_skip_sync = false;
+ dev_clear_dma_skip_sync(dev);
}
#else /* !CONFIG_DMA_NEED_SYNC */
static inline void dma_setup_need_sync(struct device *dev) { }
diff --git a/mm/hmm.c b/mm/hmm.c
index 5955f2f0c83d..c72c9ddfdb2f 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -709,7 +709,7 @@ int hmm_dma_map_alloc(struct device *dev, struct hmm_dma_map *map,
* best approximation to ensure no swiotlb buffering happens.
*/
#ifdef CONFIG_DMA_NEED_SYNC
- dma_need_sync = !dev->dma_skip_sync;
+ dma_need_sync = !dev_dma_skip_sync(dev);
#endif /* CONFIG_DMA_NEED_SYNC */
if (dma_need_sync || dma_addressing_limited(dev))
return -EOPNOTSUPP;
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v5 9/9] driver core: Replace dev->offline + ->offline_disabled with accessors
2026-04-06 23:22 ` [PATCH v5 0/9] driver core: Fix some race conditions Douglas Anderson
2026-04-06 23:22 ` [PATCH v5 4/9] driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync() Douglas Anderson
@ 2026-04-06 23:23 ` Douglas Anderson
2026-04-07 8:57 ` [PATCH v5 0/9] driver core: Fix some race conditions Marek Szyprowski
2026-04-07 22:58 ` Danilo Krummrich
3 siblings, 0 replies; 5+ messages in thread
From: Douglas Anderson @ 2026-04-06 23:23 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich, Alan Stern
Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet,
Leon Romanovsky, Christoph Hellwig, Robin Murphy, maz,
Alexander Lobakin, Saravana Kannan, Douglas Anderson, Mark Brown,
ardb, catalin.marinas, chleroy, david, driver-core, kees,
kevin.brodsky, lenb, linux-acpi, linux-arm-kernel, linux-cxl,
linux-kernel, linux-mm, linuxppc-dev, maddy, miko.lenczewski,
mpe, npiggin, osalvador, oupton, peterz, tglx, will, yangyicong,
yeoreum.yun
In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "offline" and "offline_disabled" over
to the "flags" field so modifications are safe.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).
(no changes since v4)
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- New
arch/arm64/kernel/cpufeature.c | 2 +-
.../powerpc/platforms/pseries/hotplug-memory.c | 4 ++--
drivers/acpi/scan.c | 2 +-
drivers/base/core.c | 18 +++++++++---------
drivers/base/cpu.c | 4 ++--
drivers/base/memory.c | 2 +-
include/linux/device.h | 12 ++++++------
kernel/cpu.c | 4 ++--
8 files changed, 24 insertions(+), 24 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 32c2dbcc0c64..c832aa565dc2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -4042,7 +4042,7 @@ static int enable_mismatched_32bit_el0(unsigned int cpu)
*/
lucky_winner = cpu_32bit ? cpu : cpumask_any_and(cpu_32bit_el0_mask,
cpu_active_mask);
- get_cpu_device(lucky_winner)->offline_disabled = true;
+ dev_set_offline_disabled(get_cpu_device(lucky_winner));
setup_elf_hwcaps(compat_elf_hwcaps);
elf_hwcap_fixup();
pr_info("Asymmetric 32-bit EL0 support detected on CPU %u; CPU hot-unplug disabled on CPU %u\n",
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index b2f14db59034..75f85a5da981 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -213,9 +213,9 @@ static int dlpar_change_lmb_state(struct drmem_lmb *lmb, bool online)
return -EINVAL;
}
- if (online && mem_block->dev.offline)
+ if (online && dev_offline(&mem_block->dev))
rc = device_online(&mem_block->dev);
- else if (!online && !mem_block->dev.offline)
+ else if (!online && !dev_offline(&mem_block->dev))
rc = device_offline(&mem_block->dev);
else
rc = 0;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e8cdbdb46fdb..1353adbcc234 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -122,7 +122,7 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
mutex_lock_nested(&adev->physical_node_lock, SINGLE_DEPTH_NESTING);
list_for_each_entry(pn, &adev->physical_node_list, node)
- if (device_supports_offline(pn->dev) && !pn->dev->offline) {
+ if (device_supports_offline(pn->dev) && !dev_offline(pn->dev)) {
if (uevent)
kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 30825bf83234..4f293aed879a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2788,7 +2788,7 @@ static ssize_t online_show(struct device *dev, struct device_attribute *attr,
bool val;
device_lock(dev);
- val = !dev->offline;
+ val = !dev_offline(dev);
device_unlock(dev);
return sysfs_emit(buf, "%u\n", val);
}
@@ -2913,7 +2913,7 @@ static int device_add_attrs(struct device *dev)
if (error)
goto err_remove_type_groups;
- if (device_supports_offline(dev) && !dev->offline_disabled) {
+ if (device_supports_offline(dev) && !dev_offline_disabled(dev)) {
error = device_create_file(dev, &dev_attr_online);
if (error)
goto err_remove_dev_groups;
@@ -4180,7 +4180,7 @@ static int device_check_offline(struct device *dev, void *not_used)
if (ret)
return ret;
- return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
+ return device_supports_offline(dev) && !dev_offline(dev) ? -EBUSY : 0;
}
/**
@@ -4198,7 +4198,7 @@ int device_offline(struct device *dev)
{
int ret;
- if (dev->offline_disabled)
+ if (dev_offline_disabled(dev))
return -EPERM;
ret = device_for_each_child(dev, NULL, device_check_offline);
@@ -4207,13 +4207,13 @@ int device_offline(struct device *dev)
device_lock(dev);
if (device_supports_offline(dev)) {
- if (dev->offline) {
+ if (dev_offline(dev)) {
ret = 1;
} else {
ret = dev->bus->offline(dev);
if (!ret) {
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
- dev->offline = true;
+ dev_set_offline(dev);
}
}
}
@@ -4238,11 +4238,11 @@ int device_online(struct device *dev)
device_lock(dev);
if (device_supports_offline(dev)) {
- if (dev->offline) {
+ if (dev_offline(dev)) {
ret = dev->bus->online(dev);
if (!ret) {
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
- dev->offline = false;
+ dev_clear_offline(dev);
}
} else {
ret = 1;
@@ -4716,7 +4716,7 @@ static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
if (error)
return error;
- if (device_supports_offline(dev) && !dev->offline_disabled) {
+ if (device_supports_offline(dev) && !dev_offline_disabled(dev)) {
/* Change online device attributes of @dev to @kuid/@kgid. */
error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
kuid, kgid);
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 875abdc9942e..19d288a3c80c 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -422,8 +422,8 @@ int register_cpu(struct cpu *cpu, int num)
cpu->dev.id = num;
cpu->dev.bus = &cpu_subsys;
cpu->dev.release = cpu_device_release;
- cpu->dev.offline_disabled = !cpu->hotpluggable;
- cpu->dev.offline = !cpu_online(num);
+ dev_assign_offline_disabled(&cpu->dev, !cpu->hotpluggable);
+ dev_assign_offline(&cpu->dev, !cpu_online(num));
cpu->dev.of_node = of_get_cpu_node(num, NULL);
cpu->dev.groups = common_cpu_attr_groups;
if (cpu->hotpluggable)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index a3091924918b..5005654f44fa 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -697,7 +697,7 @@ static int __add_memory_block(struct memory_block *memory)
memory->dev.id = memory->start_section_nr / sections_per_block;
memory->dev.release = memory_block_release;
memory->dev.groups = memory_memblk_attr_groups;
- memory->dev.offline = memory->state == MEM_OFFLINE;
+ dev_assign_offline(&memory->dev, memory->state == MEM_OFFLINE);
ret = device_register(&memory->dev);
if (ret) {
diff --git a/include/linux/device.h b/include/linux/device.h
index a79865a212e9..d695f7537112 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -485,6 +485,8 @@ struct device_physical_location {
* architecture supports non-coherent devices.
* @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
* ancestor device.
+ * @DEV_FLAG_OFFLINE_DISABLED: If set, the device is permanently online.
+ * @DEV_FLAG_OFFLINE: Set after successful invocation of bus type's .offline().
*/
enum struct_device_flags {
DEV_FLAG_READY_TO_PROBE = 0,
@@ -495,6 +497,8 @@ enum struct_device_flags {
DEV_FLAG_STATE_SYNCED = 5,
DEV_FLAG_DMA_COHERENT = 6,
DEV_FLAG_OF_NODE_REUSED = 7,
+ DEV_FLAG_OFFLINE_DISABLED = 8,
+ DEV_FLAG_OFFLINE = 9,
DEV_FLAG_COUNT
};
@@ -573,9 +577,6 @@ enum struct_device_flags {
* @removable: Whether the device can be removed from the system. This
* should be set by the subsystem / bus driver that discovered
* the device.
- *
- * @offline_disabled: If set, the device is permanently online.
- * @offline: Set after successful invocation of bus type's .offline().
* @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
*
* At the lowest level, every device in a Linux system is represented by an
@@ -680,9 +681,6 @@ struct device {
enum device_removable removable;
- bool offline_disabled:1;
- bool offline:1;
-
DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
};
@@ -716,6 +714,8 @@ __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
__create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
__create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
+__create_dev_flag_accessors(offline_disabled, DEV_FLAG_OFFLINE_DISABLED);
+__create_dev_flag_accessors(offline, DEV_FLAG_OFFLINE);
#undef __create_dev_flag_accessors
diff --git a/kernel/cpu.c b/kernel/cpu.c
index bc4f7a9ba64e..f975bb34915b 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2639,7 +2639,7 @@ static void cpuhp_offline_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
- dev->offline = true;
+ dev_set_offline(dev);
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
}
@@ -2648,7 +2648,7 @@ static void cpuhp_online_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
- dev->offline = false;
+ dev_clear_offline(dev);
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
}
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v5 0/9] driver core: Fix some race conditions
2026-04-06 23:22 ` [PATCH v5 0/9] driver core: Fix some race conditions Douglas Anderson
2026-04-06 23:22 ` [PATCH v5 4/9] driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync() Douglas Anderson
2026-04-06 23:23 ` [PATCH v5 9/9] driver core: Replace dev->offline + ->offline_disabled with accessors Douglas Anderson
@ 2026-04-07 8:57 ` Marek Szyprowski
2026-04-07 22:58 ` Danilo Krummrich
3 siblings, 0 replies; 5+ messages in thread
From: Marek Szyprowski @ 2026-04-07 8:57 UTC (permalink / raw)
To: Douglas Anderson, Greg Kroah-Hartman, Rafael J . Wysocki,
Danilo Krummrich, Alan Stern
Cc: Leon Romanovsky, Christoph Hellwig, Robin Murphy, driver-core,
iommu, linux-acpi, linux-arm-kernel, linux-kernel, linux-mm,
linux-pci, linux-usb, linux
On 07.04.2026 01:22, Douglas Anderson wrote:
> The main goal of this series is to fix the observed bug talked about
> in the first patch ("driver core: Don't let a device probe until it's
> ready"). That patch fixes a problem that has been observed in the real
> world and could land even if the rest of the patches are found
> unacceptable or need to be spun.
>
> That said, during patch review Danilo correctly pointed out that many
> of the bitfield accesses in "struct device" are unsafe. I added a
> bunch of patches in the series to address each one.
>
> Danilo said he's most worried about "can_match", so I put that one
> first. After that, I tried to transition bitfields to flags in reverse
> order to when the bitfield was added.
>
> Even if transitioning from bitfields to flags isn't truly needed for
> correctness, it seems silly (and wasteful of space in struct device)
> to have some in bitfields and some as flags. Thus I didn't spend time
> for each bitfield showing that it's truly needed for correctness.
>
> Transition was done semi manually. Presumably someone skilled at
> coccinelle could do a better job, but I just used sed in a heavy-
> handed manner and then reviewed/fixed the results, undoing anything my
> script got wrong. My terrible/ugly script was:
>
> var=can_match
> caps="${var^^}"
> for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
> echo $f
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
> done
>
> From v3 to v4, I transitioned to accessor functions with another ugly
> sed script. I had git format the old patches, then transformed them
> with:
>
> for f in *.patch; do
> echo $f
> sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> done
>
> ...and then did a few manual touchups for spacing.
>
> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
>
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.
The dma-mapping related bits are probably not race prone, but if you plan
to refactor that part I won't object.
Acked-by: Marek Szyprowski
> Changes in v5:
> - ready_to_prove => ready_to_probe typo
> - device_lock() while calling dev_set_ready_to_probe()
> - Add comment before "can_match = true" from Danilo.
> - undef __create_dev_flag_accessors
>
> Changes in v4:
> - Use accessor functions for flags
>
> Changes in v3:
> - Use a new "flags" bitfield
> - Add missing \n in probe error message
>
> Changes in v2:
> - Instead of adjusting the ordering, use "ready_to_probe" flag
>
> Douglas Anderson (9):
> driver core: Don't let a device probe until it's ready
> driver core: Replace dev->can_match with dev_can_match()
> driver core: Replace dev->dma_iommu with dev_dma_iommu()
> driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
> driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
> driver core: Replace dev->state_synced with dev_state_synced()
> driver core: Replace dev->dma_coherent with dev_dma_coherent()
> driver core: Replace dev->of_node_reused with dev_of_node_reused()
> driver core: Replace dev->offline + ->offline_disabled with accessors
>
> arch/arc/mm/dma.c | 4 +-
> arch/arm/mach-highbank/highbank.c | 2 +-
> arch/arm/mach-mvebu/coherency.c | 2 +-
> arch/arm/mm/dma-mapping-nommu.c | 4 +-
> arch/arm/mm/dma-mapping.c | 28 ++--
> arch/arm64/kernel/cpufeature.c | 2 +-
> arch/arm64/mm/dma-mapping.c | 2 +-
> arch/mips/mm/dma-noncoherent.c | 2 +-
> arch/powerpc/kernel/dma-iommu.c | 8 +-
> .../platforms/pseries/hotplug-memory.c | 4 +-
> arch/riscv/mm/dma-noncoherent.c | 2 +-
> drivers/acpi/scan.c | 2 +-
> drivers/base/core.c | 55 +++++---
> drivers/base/cpu.c | 4 +-
> drivers/base/dd.c | 36 ++++--
> drivers/base/memory.c | 2 +-
> drivers/base/pinctrl.c | 2 +-
> drivers/base/platform.c | 2 +-
> drivers/dma/ti/k3-udma-glue.c | 6 +-
> drivers/dma/ti/k3-udma.c | 6 +-
> drivers/iommu/dma-iommu.c | 9 +-
> drivers/iommu/iommu.c | 5 +-
> drivers/net/pcs/pcs-xpcs-plat.c | 2 +-
> drivers/of/device.c | 6 +-
> drivers/pci/of.c | 2 +-
> drivers/pci/pwrctrl/core.c | 2 +-
> drivers/regulator/bq257xx-regulator.c | 2 +-
> drivers/regulator/rk808-regulator.c | 2 +-
> drivers/tty/serial/serial_base_bus.c | 2 +-
> drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
> include/linux/device.h | 122 ++++++++++++------
> include/linux/dma-map-ops.h | 6 +-
> include/linux/dma-mapping.h | 2 +-
> include/linux/iommu-dma.h | 3 +-
> kernel/cpu.c | 4 +-
> kernel/dma/mapping.c | 12 +-
> mm/hmm.c | 2 +-
> 37 files changed, 218 insertions(+), 142 deletions(-)
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v5 0/9] driver core: Fix some race conditions
2026-04-06 23:22 ` [PATCH v5 0/9] driver core: Fix some race conditions Douglas Anderson
` (2 preceding siblings ...)
2026-04-07 8:57 ` [PATCH v5 0/9] driver core: Fix some race conditions Marek Szyprowski
@ 2026-04-07 22:58 ` Danilo Krummrich
3 siblings, 0 replies; 5+ messages in thread
From: Danilo Krummrich @ 2026-04-07 22:58 UTC (permalink / raw)
To: Douglas Anderson, m.szyprowski, Robin Murphy
Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Alan Stern,
Alexey Kardashevskiy, Johan Hovold, Eric Dumazet,
Leon Romanovsky, Christoph Hellwig, maz, Alexander Lobakin,
Saravana Kannan, Andrew Morton, Frank.Li, Jason Gunthorpe, alex,
alexander.stein, andre.przywara, andrew, andrew,
andriy.shevchenko, aou, ardb, astewart, bhelgaas, brgl, broonie,
catalin.marinas, chleroy, davem, david, devicetree, dmaengine,
driver-core, gbatra, gregory.clement, hkallweit1, iommu,
jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb,
lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
maddy, mani, miko.lenczewski, mpe, netdev, npiggin, osalvador,
oupton, pabeni, palmer, peter.ujfalusi, peterz, pjw, robh,
sebastian.hesselbarth, tglx, tsbogend, vgupta, vkoul, will,
willy, yangyicong, yeoreum.yun
On Tue Apr 7, 2026 at 1:22 AM CEST, Douglas Anderson wrote:
Applied to driver-core-testing, thanks!
> Douglas Anderson (9):
> driver core: Don't let a device probe until it's ready
> driver core: Replace dev->can_match with dev_can_match()
> driver core: Replace dev->dma_iommu with dev_dma_iommu()
> driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
> driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
> driver core: Replace dev->state_synced with dev_state_synced()
> driver core: Replace dev->dma_coherent with dev_dma_coherent()
[ Since all DEV_FLAG_DMA_COHERENT accessors are exposed unconditionally,
also drop the CONFIG guards around dev_assign_dma_coherent() in
device_initialize() to ensure a correct default value. - Danilo ]
> driver core: Replace dev->of_node_reused with dev_of_node_reused()
> driver core: Replace dev->offline + ->offline_disabled with accessors
^ permalink raw reply [flat|nested] 5+ messages in thread