Revert "Staging: zram: work around oops due to startup ordering snafu"

This reverts commit 7e24cce38a99f373450db67bf576fe73e8168d66 because it
was never appropriate for mainline.

Do not check for init flag before starting I/O - zram module is unusable
without this fix.

The oops mentioned in the reverted commit message was actually a problem
only with the zram version as present in project's own repository where
we allocate struct zram_stats_cpu upon device initialization.  OTOH, In
mainline/staging version of zram, we allocate struct stats upfront, so
this oops cannot happen in mainline version.

Checking for init_done flag in zram_make_request() results in a *no-op*
for any I/O operation since we simply always return success.  This flag
is actually set when the first write occurs on a zram disk which
triggers its initialization.

Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=25722

Reported-by: Dennis Jansen <dennis.jansen@web.de>
Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/staging/zram/zram_drv.c

@@ -435,12 +435,6 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio)
 	int ret = 0;
 	struct zram *zram = queue->queuedata;
 
-	if (unlikely(!zram->init_done)) {
-		set_bit(BIO_UPTODATE, &bio->bi_flags);
-		bio_endio(bio, 0);
-		return 0;
-	}
-
 	if (!valid_io_request(zram, bio)) {
 		zram_stat64_inc(zram, &zram->stats.invalid_io);
 		bio_io_error(bio);