From 7e24cce38a99f373450db67bf576fe73e8168d66 Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Fri, 1 Oct 2010 14:19:55 -0700
Subject: [PATCH] Staging: zram: work around oops due to startup ordering snafu
I'm getting an oops when running mkfs on zram:
NIP [d0000000030e0340] .zram_inc_stat+0x58/0x84 [zram]
[c00000006d58f720] [d0000000030e091c] .zram_make_request+0xa8/0x6a0 [zram]
[c00000006d58f840] [c00000000035795c] .generic_make_request+0x390/0x434
[c00000006d58f950] [c000000000357b14] .submit_bio+0x114/0x140
[c00000006d58fa20] [c000000000361778] .blkdev_issue_discard+0x1ac/0x250
[c00000006d58fb10] [c000000000361f68] .blkdev_ioctl+0x358/0x7fc
[c00000006d58fbd0] [c0000000001c1c1c] .block_ioctl+0x6c/0x90
[c00000006d58fc70] [c0000000001984c4] .do_vfs_ioctl+0x660/0x6d4
[c00000006d58fd70] [c0000000001985a0] .SyS_ioctl+0x68/0xb0
Since disksize no longer starts as 0 it looks like we can call
zram_make_request before the device has been initialised. The patch below
fixes the immediate problem but this would go away if we move the
initialisation function elsewhere (as suggested in another thread).
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/staging/zram/zram_drv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index c5f84ee3d28a9..72f1b9ce577b3 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -435,6 +435,12 @@ 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);
--
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