Hi,
Since patch #7 and #8 from the series:
[PATCH v1 00/25] seqlock: Extend seqcount API with associated locks https://lore.kernel.org/lkml/20200519214547.352050-1-a.darwish@linutronix.de
are now pending on the lockdep/x86 IRQ state tracking patch series:
[PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi https://lkml.kernel.org/r/20200529212728.795169701@infradead.org
[PATCH v3 0/5] lockdep: Change IRQ state tracking to use per-cpu variables https://lkml.kernel.org/r/20200529213550.683440625@infradead.org
This is a repost only of the seqcount_t call sites bugfixes that were on top of the seqlock patch series.
These fixes are independent, and can thus be merged on their own. I'm reposting them now so they can at least hit -rc2 or -rc3.
Changelog-v2:
- patch #1: Add a missing up_read() on netdev_get_name() error path exit. Thanks to Dan/kbuild-bot report.
- patch #4: new patch, invalid preemptible context found by the new lockdep checks added in the seqlock series + kbuild-bot.
Thanks,
8<--------------
Ahmed S. Darwish (6): net: core: device_rename: Use rwsem instead of a seqcount net: phy: fixed_phy: Remove unused seqcount u64_stats: Document writer non-preemptibility requirement net: mdiobus: Disable preemption upon u64_stats update block: nr_sects_write(): Disable preemption on seqcount write dma-buf: Remove custom seqcount lockdep class key
block/blk.h | 2 ++ drivers/dma-buf/dma-resv.c | 9 +------ drivers/net/phy/fixed_phy.c | 26 ++++++++------------ drivers/net/phy/mdio_bus.c | 2 ++ include/linux/dma-resv.h | 2 -- include/linux/u64_stats_sync.h | 43 ++++++++++++++++++---------------- net/core/dev.c | 40 ++++++++++++++----------------- 7 files changed, 56 insertions(+), 68 deletions(-)
base-commit: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 -- 2.20.1
Commit 3c3b177a9369 ("reservation: add support for read-only access using rcu") introduced a sequence counter to manage updates to reservations. Back then, the reservation object initializer reservation_object_init() was always inlined.
Having the sequence counter initialization inlined meant that each of the call sites would have a different lockdep class key, which would've broken lockdep's deadlock detection. The aforementioned commit thus introduced, and exported, a custom seqcount lockdep class key and name.
The commit 8735f16803f00 ("dma-buf: cleanup reservation_object_init...") transformed the reservation object initializer to a normal non-inlined C function. seqcount_init(), which automatically defines the seqcount lockdep class key and must be called non-inlined, can now be safely used.
Remove the seqcount custom lockdep class key, name, and export. Use seqcount_init() inside the dma reservation object initializer.
Signed-off-by: Ahmed S. Darwish a.darwish@linutronix.de Reviewed-by: Sebastian Andrzej Siewior bigeasy@linutronix.de --- drivers/dma-buf/dma-resv.c | 9 +-------- include/linux/dma-resv.h | 2 -- 2 files changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 4264e64788c4..590ce7ad60a0 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -50,12 +50,6 @@ DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class);
-struct lock_class_key reservation_seqcount_class; -EXPORT_SYMBOL(reservation_seqcount_class); - -const char reservation_seqcount_string[] = "reservation_seqcount"; -EXPORT_SYMBOL(reservation_seqcount_string); - /** * dma_resv_list_alloc - allocate fence list * @shared_max: number of fences we need space for @@ -134,9 +128,8 @@ subsys_initcall(dma_resv_lockdep); void dma_resv_init(struct dma_resv *obj) { ww_mutex_init(&obj->lock, &reservation_ww_class); + seqcount_init(&obj->seq);
- __seqcount_init(&obj->seq, reservation_seqcount_string, - &reservation_seqcount_class); RCU_INIT_POINTER(obj->fence, NULL); RCU_INIT_POINTER(obj->fence_excl, NULL); } diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index ee50d10f052b..a6538ae7d93f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -46,8 +46,6 @@ #include <linux/rcupdate.h>
extern struct ww_class reservation_ww_class; -extern struct lock_class_key reservation_seqcount_class; -extern const char reservation_seqcount_string[];
/** * struct dma_resv_list - a list of shared fences
On Wed, Jun 03, 2020 at 04:49:49PM +0200, Ahmed S. Darwish wrote:
Commit 3c3b177a9369 ("reservation: add support for read-only access using rcu") introduced a sequence counter to manage updates to reservations. Back then, the reservation object initializer reservation_object_init() was always inlined.
Having the sequence counter initialization inlined meant that each of the call sites would have a different lockdep class key, which would've broken lockdep's deadlock detection. The aforementioned commit thus introduced, and exported, a custom seqcount lockdep class key and name.
The commit 8735f16803f00 ("dma-buf: cleanup reservation_object_init...") transformed the reservation object initializer to a normal non-inlined C function. seqcount_init(), which automatically defines the seqcount lockdep class key and must be called non-inlined, can now be safely used.
Remove the seqcount custom lockdep class key, name, and export. Use seqcount_init() inside the dma reservation object initializer.
Signed-off-by: Ahmed S. Darwish a.darwish@linutronix.de Reviewed-by: Sebastian Andrzej Siewior bigeasy@linutronix.de
Patch lgtm, and Ahmed says plan is that this should land through -tip since it's part of a larger series, so
Acked-by: Daniel Vetter daniel.vetter@ffwll.ch
for merging through whatever tree/branch fits bets. I don't expect conflicts here, nothing in-flight touching this. I expect this will show up in 5.9-rc1 or so.
Cheers, Daniel
drivers/dma-buf/dma-resv.c | 9 +-------- include/linux/dma-resv.h | 2 -- 2 files changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 4264e64788c4..590ce7ad60a0 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -50,12 +50,6 @@ DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class);
-struct lock_class_key reservation_seqcount_class; -EXPORT_SYMBOL(reservation_seqcount_class);
-const char reservation_seqcount_string[] = "reservation_seqcount"; -EXPORT_SYMBOL(reservation_seqcount_string);
/**
- dma_resv_list_alloc - allocate fence list
- @shared_max: number of fences we need space for
@@ -134,9 +128,8 @@ subsys_initcall(dma_resv_lockdep); void dma_resv_init(struct dma_resv *obj) { ww_mutex_init(&obj->lock, &reservation_ww_class);
- seqcount_init(&obj->seq);
- __seqcount_init(&obj->seq, reservation_seqcount_string,
&reservation_seqcount_class);} diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index ee50d10f052b..a6538ae7d93f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -46,8 +46,6 @@ #include <linux/rcupdate.h>
extern struct ww_class reservation_ww_class; -extern struct lock_class_key reservation_seqcount_class; -extern const char reservation_seqcount_string[];
/**
- struct dma_resv_list - a list of shared fences
-- 2.20.1
On Wed, Jun 03, 2020 at 04:49:43PM +0200, Ahmed S. Darwish wrote:
Hi,
Since patch #7 and #8 from the series:
[PATCH v1 00/25] seqlock: Extend seqcount API with associated locks https://lore.kernel.org/lkml/20200519214547.352050-1-a.darwish@linutronix.de
are now pending on the lockdep/x86 IRQ state tracking patch series:
[PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi https://lkml.kernel.org/r/20200529212728.795169701@infradead.org
[PATCH v3 0/5] lockdep: Change IRQ state tracking to use per-cpu variables https://lkml.kernel.org/r/20200529213550.683440625@infradead.org
This is a repost only of the seqcount_t call sites bugfixes that were on top of the seqlock patch series.
These fixes are independent, and can thus be merged on their own. I'm reposting them now so they can at least hit -rc2 or -rc3.
I'm confused on what I should do with patch 6 here for dma-buf. Looks like just a good cleanup/prep work, so I'd queue it for linux-next and 5.9, but sounds like you want this in earlier. Do you need this in 5.8-rc for some work meant for 5.9? Will this go in through some topic branch directly? Should I apply it?
Patch itself lgtm, I'm just confused what I should do with it. -Daniel
Changelog-v2:
patch #1: Add a missing up_read() on netdev_get_name() error path exit. Thanks to Dan/kbuild-bot report.
patch #4: new patch, invalid preemptible context found by the new lockdep checks added in the seqlock series + kbuild-bot.
Thanks,
8<--------------
Ahmed S. Darwish (6): net: core: device_rename: Use rwsem instead of a seqcount net: phy: fixed_phy: Remove unused seqcount u64_stats: Document writer non-preemptibility requirement net: mdiobus: Disable preemption upon u64_stats update block: nr_sects_write(): Disable preemption on seqcount write dma-buf: Remove custom seqcount lockdep class key
block/blk.h | 2 ++ drivers/dma-buf/dma-resv.c | 9 +------ drivers/net/phy/fixed_phy.c | 26 ++++++++------------ drivers/net/phy/mdio_bus.c | 2 ++ include/linux/dma-resv.h | 2 -- include/linux/u64_stats_sync.h | 43 ++++++++++++++++++---------------- net/core/dev.c | 40 ++++++++++++++----------------- 7 files changed, 56 insertions(+), 68 deletions(-)
base-commit: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162
2.20.1
On Thu, Jun 04, 2020 at 09:28:41AM +0200, Daniel Vetter wrote:
On Wed, Jun 03, 2020 at 04:49:43PM +0200, Ahmed S. Darwish wrote:
Hi,
Since patch #7 and #8 from the series:
[PATCH v1 00/25] seqlock: Extend seqcount API with associated locks https://lore.kernel.org/lkml/20200519214547.352050-1-a.darwish@linutronix.de
are now pending on the lockdep/x86 IRQ state tracking patch series:
[PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi https://lkml.kernel.org/r/20200529212728.795169701@infradead.org
[PATCH v3 0/5] lockdep: Change IRQ state tracking to use per-cpu variables https://lkml.kernel.org/r/20200529213550.683440625@infradead.org
This is a repost only of the seqcount_t call sites bugfixes that were on top of the seqlock patch series.
These fixes are independent, and can thus be merged on their own. I'm reposting them now so they can at least hit -rc2 or -rc3.
I'm confused on what I should do with patch 6 here for dma-buf. Looks like just a good cleanup/prep work, so I'd queue it for linux-next and 5.9, but sounds like you want this in earlier. Do you need this in 5.8-rc for some work meant for 5.9? Will this go in through some topic branch directly? Should I apply it?
Patch itself lgtm, I'm just confused what I should do with it.
My apologies for the confusion. The cover letter is indeed misleading w.r.t. the dma-buf patch. It isn't a bugfix, so it shouldn't hit -rc.
Since without this patch compiling the seqcount series will fail, it will be best to merge it through tip instead.
So all I need for now is a reviewed-by tag :) I will forwoard it to the tip tree afterwards.
Thanks,
-- Ahmed S. Darwish Linutronix GmbH
From: "Ahmed S. Darwish" a.darwish@linutronix.de Date: Wed, 3 Jun 2020 16:49:43 +0200
Since patch #7 and #8 from the series:
[PATCH v1 00/25] seqlock: Extend seqcount API with associated locks https://lore.kernel.org/lkml/20200519214547.352050-1-a.darwish@linutronix.de
are now pending on the lockdep/x86 IRQ state tracking patch series:
[PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi https://lkml.kernel.org/r/20200529212728.795169701@infradead.org
[PATCH v3 0/5] lockdep: Change IRQ state tracking to use per-cpu variables https://lkml.kernel.org/r/20200529213550.683440625@infradead.org
This is a repost only of the seqcount_t call sites bugfixes that were on top of the seqlock patch series.
These fixes are independent, and can thus be merged on their own. I'm reposting them now so they can at least hit -rc2 or -rc3.
Changelog-v2:
patch #1: Add a missing up_read() on netdev_get_name() error path exit. Thanks to Dan/kbuild-bot report.
patch #4: new patch, invalid preemptible context found by the new lockdep checks added in the seqlock series + kbuild-bot.
I'll apply patches 1-4 to the net tree.
dri-devel@lists.freedesktop.org
-
Ahmed S. Darwish -
Daniel Vetter -
David Miller