mainline inclusion
from mainline-v5.12-rc1
commit d13c613f
category: bugfix
bugzilla: 172149 https://gitee.com/openeuler/kernel/issues/I4CZ7H
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d13c613f136c

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Add a macro cond_yield that branches to a specified label when called if
the TIF_NEED_RESCHED flag is set and decreasing the preempt count would
make the task preemptible again, resulting in a schedule to occur. This
can be used by kernel mode SIMD code that keeps a lot of state in SIMD
registers, which would make chunking the input in order to perform the
cond_resched() check from C code disproportionately costly.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210203113626.220151-2-ardb@kernel.orgSigned-off-by: NWill Deacon <will@kernel.org>
Signed-off-by: NWei Li <liwei391@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>