Commit Graph

3 Commits (ee8e8f92a730afc17ab8be6e86df6b9a23b8ebc6)

Author SHA1 Message Date
Emilio G. Cota d12f730948 seqlock: read sequence number atomically
With this change we make sure that the compiler will not
optimise the read of the sequence number in any way.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1440375847-17603-8-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-07 18:12:39 +02:00
Emilio G. Cota 123fdbac9b seqlock: add missing 'inline' to seqlock_read_retry
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1440375847-17603-7-git-send-email-cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-07 18:12:31 +02:00
Paolo Bonzini ea753d81e8 seqlock: introduce read-write seqlock
Seqlock implementation for QEMU. Usage idiom

reader:
    do {
        start = seqlock_read_begin(&sl);
        ...
    } while (seqlock_read_retry(&sl, start));

writer:
    seqlock_write_lock(&sl);
    ...
    seqlock_write_unlock(&sl);

initialization:
    seqlock_init(QemuSeqLock *sl, QemuMutex *mutex)

    mutex could be NULL if the caller will provide its own protection
    for concurrent write sides (typically using the BQL).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-17 17:24:15 +02:00