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author | Dave Airlie <airlied@redhat.com> | 2023-08-24 07:26:06 +1000 |
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committer | Dave Airlie <airlied@redhat.com> | 2023-08-24 07:26:06 +1000 |
commit | fdebffeba8b877368ddcc139c26278c1c97931a4 (patch) | |
tree | 5ebf85a3e26d55ea388aa7a8608222205a4d59ba /include/linux/mm_types.h | |
parent | cacaeb27ade4b793c456179bb6eda4592d206cd8 (diff) | |
parent | 706a741595047797872e669b3101429ab8d378ef (diff) | |
download | linux-stable-fdebffeba8b877368ddcc139c26278c1c97931a4.tar.gz linux-stable-fdebffeba8b877368ddcc139c26278c1c97931a4.tar.bz2 linux-stable-fdebffeba8b877368ddcc139c26278c1c97931a4.zip |
BackMerge tag 'v6.5-rc7' into drm-next
Linux 6.5-rc7
This is needed for the CI stuff and the msm pull has fixes in it.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'include/linux/mm_types.h')
-rw-r--r-- | include/linux/mm_types.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index de10fc797c8e..5e74ce4a28cd 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -514,6 +514,20 @@ struct vm_area_struct { }; #ifdef CONFIG_PER_VMA_LOCK + /* + * Can only be written (using WRITE_ONCE()) while holding both: + * - mmap_lock (in write mode) + * - vm_lock->lock (in write mode) + * Can be read reliably while holding one of: + * - mmap_lock (in read or write mode) + * - vm_lock->lock (in read or write mode) + * Can be read unreliably (using READ_ONCE()) for pessimistic bailout + * while holding nothing (except RCU to keep the VMA struct allocated). + * + * This sequence counter is explicitly allowed to overflow; sequence + * counter reuse can only lead to occasional unnecessary use of the + * slowpath. + */ int vm_lock_seq; struct vma_lock *vm_lock; @@ -679,6 +693,20 @@ struct mm_struct { * by mmlist_lock */ #ifdef CONFIG_PER_VMA_LOCK + /* + * This field has lock-like semantics, meaning it is sometimes + * accessed with ACQUIRE/RELEASE semantics. + * Roughly speaking, incrementing the sequence number is + * equivalent to releasing locks on VMAs; reading the sequence + * number can be part of taking a read lock on a VMA. + * + * Can be modified under write mmap_lock using RELEASE + * semantics. + * Can be read with no other protection when holding write + * mmap_lock. + * Can be read with ACQUIRE semantics if not holding write + * mmap_lock. + */ int mm_lock_seq; #endif |