kernel/linux.git/include, branch v4.19.174

kthread: Extract KTHREAD_IS_PER_CPU

2021-02-07T13:48:38+00:00

[ Upstream commit ac687e6e8c26181a33270efd1a2e2241377924b0 ] There is a need to distinguish geniune per-cpu kthreads from kthreads that happen to have a single CPU affinity. Geniune per-cpu kthreads are kthreads that are CPU affine for correctness, these will obviously have PF_KTHREAD set, but must also have PF_NO_SETAFFINITY set, lest userspace modify their affinity and ruins things. However, these two things are not sufficient, PF_NO_SETAFFINITY is also set on other tasks that have their affinities controlled through other means, like for instance workqueues. Therefore another bit is needed; it turns out kthread_create_per_cpu() already has such a bit: KTHREAD_IS_PER_CPU, which is used to make kthread_park()/kthread_unpark() work correctly. Expose this flag and remove the implicit setting of it from kthread_create_on_cpu(); the io_uring usage of it seems dubious at best. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210121103506.557620262@infradead.org Signed-off-by: Sasha Levin

tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN

2021-02-03T22:23:27+00:00

commit 62d9f1a6945ba69c125e548e72a36d203b30596e upstream. Upon receiving a cumulative ACK that changes the congestion state from Disorder to Open, the TLP timer is not set. If the sender is app-limited, it can only wait for the RTO timer to expire and retransmit. The reason for this is that the TLP timer is set before the congestion state changes in tcp_ack(), so we delay the time point of calling tcp_set_xmit_timer() until after tcp_fastretrans_alert() returns and remove the FLAG_SET_XMIT_TIMER from ack_flag when the RACK reorder timer is set. This commit has two additional benefits: 1) Make sure to reset RTO according to RFC6298 when receiving ACK, to avoid spurious RTO caused by RTO timer early expires. 2) Reduce the xmit timer reschedule once per ACK when the RACK reorder timer is set. Fixes: df92c8394e6e ("tcp: fix xmit timer to only be reset if data ACKed/SACKed") Link: https://lore.kernel.org/netdev/1611311242-6675-1-git-send-email-yangpc@wangsu.com Signed-off-by: Pengcheng Yang Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Cc: Eric Dumazet Link: https://lore.kernel.org/r/1611464834-23030-1-git-send-email-yangpc@wangsu.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

iommu/vt-d: Don't dereference iommu_device if IOMMU_API is not built

2021-02-03T22:23:26+00:00

commit 9def3b1a07c41e21c68a0eb353e3e569fdd1d2b1 upstream. Since commit c40aaaac1018 ("iommu/vt-d: Gracefully handle DMAR units with no supported address widths") dmar.c needs struct iommu_device to be selected. We can drop this dependency by not dereferencing struct iommu_device if IOMMU_API is not selected and by reusing the information stored in iommu->drhd->ignored instead. This fixes the following build error when IOMMU_API is not selected: drivers/iommu/dmar.c: In function ‘free_iommu’: drivers/iommu/dmar.c:1139:41: error: ‘struct iommu_device’ has no member named ‘ops’ 1139 | if (intel_iommu_enabled && iommu->iommu.ops) { ^ Fixes: c40aaaac1018 ("iommu/vt-d: Gracefully handle DMAR units with no supported address widths") Signed-off-by: Bartosz Golaszewski Acked-by: Lu Baolu Acked-by: David Woodhouse Link: https://lore.kernel.org/r/20201013073055.11262-1-brgl@bgdev.pl Signed-off-by: Joerg Roedel [ - context change due to moving drivers/iommu/dmar.c to drivers/iommu/intel/dmar.c - set the drhr in the iommu like in upstream commit b1012ca8dc4f ("iommu/vt-d: Skip TE disabling on quirky gfx dedicated iommu") ] Signed-off-by: Filippo Sironi Signed-off-by: Greg Kroah-Hartman

writeback: Drop I_DIRTY_TIME_EXPIRE

2021-01-30T12:32:13+00:00

commit 5fcd57505c002efc5823a7355e21f48dd02d5a51 upstream. The only use of I_DIRTY_TIME_EXPIRE is to detect in __writeback_single_inode() that inode got there because flush worker decided it's time to writeback the dirty inode time stamps (either because we are syncing or because of age). However we can detect this directly in __writeback_single_inode() and there's no need for the strange propagation with I_DIRTY_TIME_EXPIRE flag. Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

futex: Add mutex around futex exit

2021-01-30T12:32:12+00:00

commit 3f186d974826847a07bc7964d79ec4eded475ad9 upstream The mutex will be used in subsequent changes to replace the busy looping of a waiter when the futex owner is currently executing the exit cleanup to prevent a potential live lock. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.845798895@linutronix.de Signed-off-by: Greg Kroah-Hartman

futex: Mark the begin of futex exit explicitly

2021-01-30T12:32:11+00:00

commit 18f694385c4fd77a09851fd301236746ca83f3cb upstream Instead of relying on PF_EXITING use an explicit state for the futex exit and set it in the futex exit function. This moves the smp barrier and the lock/unlock serialization into the futex code. As with the DEAD state this is restricted to the exit path as exec continues to use the same task struct. This allows to simplify that logic in a next step. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.539409004@linutronix.de Signed-off-by: Greg Kroah-Hartman

futex: Split futex_mm_release() for exit/exec

2021-01-30T12:32:11+00:00

commit 150d71584b12809144b8145b817e83b81158ae5f upstream To allow separate handling of the futex exit state in the futex exit code for exit and exec, split futex_mm_release() into two functions and invoke them from the corresponding exit/exec_mm_release() callsites. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.332094221@linutronix.de Signed-off-by: Greg Kroah-Hartman

exit/exec: Seperate mm_release()

2021-01-30T12:32:11+00:00

commit 4610ba7ad877fafc0a25a30c6c82015304120426 upstream mm_release() contains the futex exit handling. mm_release() is called from do_exit()->exit_mm() and from exec()->exec_mm(). In the exit_mm() case PF_EXITING and the futex state is updated. In the exec_mm() case these states are not touched. As the futex exit code needs further protections against exit races, this needs to be split into two functions. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de Signed-off-by: Greg Kroah-Hartman

futex: Replace PF_EXITPIDONE with a state

2021-01-30T12:32:11+00:00

commit 3d4775df0a89240f671861c6ab6e8d59af8e9e41 upstream The futex exit handling relies on PF_ flags. That's suboptimal as it requires a smp_mb() and an ugly lock/unlock of the exiting tasks pi_lock in the middle of do_exit() to enforce the observability of PF_EXITING in the futex code. Add a futex_state member to task_struct and convert the PF_EXITPIDONE logic over to the new state. The PF_EXITING dependency will be cleaned up in a later step. This prepares for handling various futex exit issues later. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.149449274@linutronix.de Signed-off-by: Greg Kroah-Hartman

futex: Move futex exit handling into futex code

2021-01-30T12:32:11+00:00

commit ba31c1a48538992316cc71ce94fa9cd3e7b427c0 upstream The futex exit handling is #ifdeffed into mm_release() which is not pretty to begin with. But upcoming changes to address futex exit races need to add more functionality to this exit code. Split it out into a function, move it into futex code and make the various futex exit functions static. Preparatory only and no functional change. Folded build fix from Borislav. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191106224556.049705556@linutronix.de Signed-off-by: Greg Kroah-Hartman