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    Subject[PATCH 4.14 16/35] pstore: Remove needless lock during console writes
    Date
    From: Kees Cook <keescook@chromium.org>

    commit b77fa617a2ff4d6beccad3d3d4b3a1f2d10368aa upstream.

    Since the console writer does not use the preallocated crash dump buffer
    any more, there is no reason to perform locking around it.

    Fixes: 70ad35db3321 ("pstore: Convert console write to use ->write_buf")
    Signed-off-by: Kees Cook <keescook@chromium.org>
    Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/pstore/platform.c | 29 ++++++-----------------------
    1 file changed, 6 insertions(+), 23 deletions(-)

    --- a/fs/pstore/platform.c
    +++ b/fs/pstore/platform.c
    @@ -597,31 +597,14 @@ static void pstore_unregister_kmsg(void)
    #ifdef CONFIG_PSTORE_CONSOLE
    static void pstore_console_write(struct console *con, const char *s, unsigned c)
    {
    - const char *e = s + c;
    + struct pstore_record record;

    - while (s < e) {
    - struct pstore_record record;
    - unsigned long flags;
    + pstore_record_init(&record, psinfo);
    + record.type = PSTORE_TYPE_CONSOLE;

    - pstore_record_init(&record, psinfo);
    - record.type = PSTORE_TYPE_CONSOLE;
    -
    - if (c > psinfo->bufsize)
    - c = psinfo->bufsize;
    -
    - if (oops_in_progress) {
    - if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
    - break;
    - } else {
    - spin_lock_irqsave(&psinfo->buf_lock, flags);
    - }
    - record.buf = (char *)s;
    - record.size = c;
    - psinfo->write(&record);
    - spin_unlock_irqrestore(&psinfo->buf_lock, flags);
    - s += c;
    - c = e - s;
    - }
    + record.buf = (char *)s;
    + record.size = c;
    + psinfo->write(&record);
    }

    static struct console pstore_console = {

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