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ARC: atomics: unbork atomic_fetch_##op()
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In 4.19-rc1, Eugeniy reported weird boot and IO errors on ARC HSDK

| INFO: task syslogd:77 blocked for more than 10 seconds.
|       Not tainted 4.19.0-rc1-00007-gf213acea4e88 #40
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
| message.
| syslogd         D    0    77     76 0x00000000
|
| Stack Trace:
|  __switch_to+0x0/0xac
|  __schedule+0x1b2/0x730
|  io_schedule+0x5c/0xc0
|  __lock_page+0x98/0xdc
|  find_lock_entry+0x38/0x100
|  shmem_getpage_gfp.isra.3+0x82/0xbfc
|  shmem_fault+0x46/0x138
|  handle_mm_fault+0x5bc/0x924
|  do_page_fault+0x100/0x2b8
|  ret_from_exception+0x0/0x8

He bisected to 84c6591 ("locking/atomics,
asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()")

This commit however only unmasked the real issue introduced by commit
4aef66c ("locking/atomic, arch/arc: Fix build") which missed the
retry-if-scond-failed branch in atomic_fetch_##op() macros.

The bisected commit started using atomic_fetch_##op() macros for building
the rest of atomics.

Fixes: 4aef66c ("locking/atomic, arch/arc: Fix build")
Reported-by: Eugeniy Paltsev <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>
[vgupta: wrote changelog]
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wildea01 authored and vineetgarc committed Aug 31, 2018
1 parent 2b52e2a commit 3fcbb82
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/arc/include/asm/atomic.h
Original file line number Diff line number Diff line change
Expand Up @@ -84,7 +84,7 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \
"1: llock %[orig], [%[ctr]] \n" \
" " #asm_op " %[val], %[orig], %[i] \n" \
" scond %[val], [%[ctr]] \n" \
" \n" \
" bnz 1b \n" \
: [val] "=&r" (val), \
[orig] "=&r" (orig) \
: [ctr] "r" (&v->counter), \
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