switch logger to ->write_iter()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>hifive-unleashed-5.1
Al Viro
parent
512b226815
commit
cd678fce42
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@ -411,69 +411,18 @@ static void fix_up_readers(struct logger_log *log, size_t len)
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}
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/*
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* do_write_log - writes 'len' bytes from 'buf' to 'log'
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*
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* The caller needs to hold log->mutex.
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*/
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static void do_write_log(struct logger_log *log, const void *buf, size_t count)
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{
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size_t len;
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len = min(count, log->size - log->w_off);
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memcpy(log->buffer + log->w_off, buf, len);
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if (count != len)
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memcpy(log->buffer, buf + len, count - len);
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log->w_off = logger_offset(log, log->w_off + count);
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}
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/*
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* do_write_log_user - writes 'len' bytes from the user-space buffer 'buf' to
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* the log 'log'
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*
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* The caller needs to hold log->mutex.
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*
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* Returns 'count' on success, negative error code on failure.
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*/
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static ssize_t do_write_log_from_user(struct logger_log *log,
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const void __user *buf, size_t count)
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{
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size_t len;
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len = min(count, log->size - log->w_off);
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if (len && copy_from_user(log->buffer + log->w_off, buf, len))
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return -EFAULT;
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if (count != len)
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if (copy_from_user(log->buffer, buf + len, count - len))
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/*
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* Note that by not updating w_off, this abandons the
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* portion of the new entry that *was* successfully
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* copied, just above. This is intentional to avoid
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* message corruption from missing fragments.
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*/
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return -EFAULT;
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log->w_off = logger_offset(log, log->w_off + count);
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return count;
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}
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/*
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* logger_aio_write - our write method, implementing support for write(),
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* logger_write_iter - our write method, implementing support for write(),
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* writev(), and aio_write(). Writes are our fast path, and we try to optimize
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* them above all else.
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*/
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static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t ppos)
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static ssize_t logger_write_iter(struct kiocb *iocb, struct iov_iter *from)
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{
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struct logger_log *log = file_get_log(iocb->ki_filp);
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size_t orig;
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struct logger_entry header;
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struct timespec now;
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ssize_t ret = 0;
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size_t len, count;
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count = min_t(size_t, iocb->ki_nbytes, LOGGER_ENTRY_MAX_PAYLOAD);
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now = current_kernel_time();
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@ -482,7 +431,7 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
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header.sec = now.tv_sec;
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header.nsec = now.tv_nsec;
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header.euid = current_euid();
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header.len = min_t(size_t, iocb->ki_nbytes, LOGGER_ENTRY_MAX_PAYLOAD);
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header.len = count;
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header.hdr_size = sizeof(struct logger_entry);
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/* null writes succeed, return zero */
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@ -491,8 +440,6 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
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mutex_lock(&log->mutex);
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orig = log->w_off;
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/*
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* Fix up any readers, pulling them forward to the first readable
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* entry after (what will be) the new write offset. We do this now
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@ -501,33 +448,35 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
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*/
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fix_up_readers(log, sizeof(struct logger_entry) + header.len);
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do_write_log(log, &header, sizeof(struct logger_entry));
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len = min(sizeof(header), log->size - log->w_off);
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memcpy(log->buffer + log->w_off, &header, len);
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memcpy(log->buffer, (char *)&header + len, sizeof(header) - len);
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while (nr_segs-- > 0) {
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size_t len;
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ssize_t nr;
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len = min(count, log->size - log->w_off);
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/* figure out how much of this vector we can keep */
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len = min_t(size_t, iov->iov_len, header.len - ret);
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/* write out this segment's payload */
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nr = do_write_log_from_user(log, iov->iov_base, len);
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if (unlikely(nr < 0)) {
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log->w_off = orig;
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mutex_unlock(&log->mutex);
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return nr;
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}
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iov++;
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ret += nr;
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if (copy_from_iter(log->buffer + log->w_off, len, from) != len) {
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/*
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* Note that by not updating w_off, this abandons the
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* portion of the new entry that *was* successfully
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* copied, just above. This is intentional to avoid
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* message corruption from missing fragments.
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*/
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mutex_unlock(&log->mutex);
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return -EFAULT;
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}
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if (copy_from_iter(log->buffer, count - len, from) != count - len) {
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mutex_unlock(&log->mutex);
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return -EFAULT;
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}
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log->w_off = logger_offset(log, log->w_off + count);
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mutex_unlock(&log->mutex);
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/* wake up any blocked readers */
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wake_up_interruptible(&log->wq);
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return ret;
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return len;
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}
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static struct logger_log *get_log_from_minor(int minor)
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@ -736,7 +685,7 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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static const struct file_operations logger_fops = {
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.owner = THIS_MODULE,
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.read = logger_read,
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.aio_write = logger_aio_write,
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.write_iter = logger_write_iter,
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.poll = logger_poll,
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.unlocked_ioctl = logger_ioctl,
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.compat_ioctl = logger_ioctl,
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