From cd678fce428018dee0c9345ed63ebf9920d9902f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 23 Aug 2014 12:20:37 -0400 Subject: [PATCH] switch logger to ->write_iter() Signed-off-by: Al Viro --- drivers/staging/android/logger.c | 105 ++++++++----------------------- 1 file changed, 27 insertions(+), 78 deletions(-) diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index 0bf0d24d12d5..28b93d39a94e 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -411,69 +411,18 @@ static void fix_up_readers(struct logger_log *log, size_t len) } /* - * do_write_log - writes 'len' bytes from 'buf' to 'log' - * - * The caller needs to hold log->mutex. - */ -static void do_write_log(struct logger_log *log, const void *buf, size_t count) -{ - size_t len; - - len = min(count, log->size - log->w_off); - memcpy(log->buffer + log->w_off, buf, len); - - if (count != len) - memcpy(log->buffer, buf + len, count - len); - - log->w_off = logger_offset(log, log->w_off + count); - -} - -/* - * do_write_log_user - writes 'len' bytes from the user-space buffer 'buf' to - * the log 'log' - * - * The caller needs to hold log->mutex. - * - * Returns 'count' on success, negative error code on failure. - */ -static ssize_t do_write_log_from_user(struct logger_log *log, - const void __user *buf, size_t count) -{ - size_t len; - - len = min(count, log->size - log->w_off); - if (len && copy_from_user(log->buffer + log->w_off, buf, len)) - return -EFAULT; - - if (count != len) - if (copy_from_user(log->buffer, buf + len, count - len)) - /* - * Note that by not updating w_off, this abandons the - * portion of the new entry that *was* successfully - * copied, just above. This is intentional to avoid - * message corruption from missing fragments. - */ - return -EFAULT; - - log->w_off = logger_offset(log, log->w_off + count); - - return count; -} - -/* - * logger_aio_write - our write method, implementing support for write(), + * logger_write_iter - our write method, implementing support for write(), * writev(), and aio_write(). Writes are our fast path, and we try to optimize * them above all else. */ -static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t ppos) +static ssize_t logger_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct logger_log *log = file_get_log(iocb->ki_filp); - size_t orig; struct logger_entry header; struct timespec now; - ssize_t ret = 0; + size_t len, count; + + count = min_t(size_t, iocb->ki_nbytes, LOGGER_ENTRY_MAX_PAYLOAD); now = current_kernel_time(); @@ -482,7 +431,7 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, header.sec = now.tv_sec; header.nsec = now.tv_nsec; header.euid = current_euid(); - header.len = min_t(size_t, iocb->ki_nbytes, LOGGER_ENTRY_MAX_PAYLOAD); + header.len = count; header.hdr_size = sizeof(struct logger_entry); /* null writes succeed, return zero */ @@ -491,8 +440,6 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, mutex_lock(&log->mutex); - orig = log->w_off; - /* * Fix up any readers, pulling them forward to the first readable * entry after (what will be) the new write offset. We do this now @@ -501,33 +448,35 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, */ fix_up_readers(log, sizeof(struct logger_entry) + header.len); - do_write_log(log, &header, sizeof(struct logger_entry)); + len = min(sizeof(header), log->size - log->w_off); + memcpy(log->buffer + log->w_off, &header, len); + memcpy(log->buffer, (char *)&header + len, sizeof(header) - len); - while (nr_segs-- > 0) { - size_t len; - ssize_t nr; + len = min(count, log->size - log->w_off); - /* figure out how much of this vector we can keep */ - len = min_t(size_t, iov->iov_len, header.len - ret); - - /* write out this segment's payload */ - nr = do_write_log_from_user(log, iov->iov_base, len); - if (unlikely(nr < 0)) { - log->w_off = orig; - mutex_unlock(&log->mutex); - return nr; - } - - iov++; - ret += nr; + if (copy_from_iter(log->buffer + log->w_off, len, from) != len) { + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ + mutex_unlock(&log->mutex); + return -EFAULT; } + if (copy_from_iter(log->buffer, count - len, from) != count - len) { + mutex_unlock(&log->mutex); + return -EFAULT; + } + + log->w_off = logger_offset(log, log->w_off + count); mutex_unlock(&log->mutex); /* wake up any blocked readers */ wake_up_interruptible(&log->wq); - return ret; + return len; } static struct logger_log *get_log_from_minor(int minor) @@ -736,7 +685,7 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg) static const struct file_operations logger_fops = { .owner = THIS_MODULE, .read = logger_read, - .aio_write = logger_aio_write, + .write_iter = logger_write_iter, .poll = logger_poll, .unlocked_ioctl = logger_ioctl, .compat_ioctl = logger_ioctl,