mtd: tests: stresstest: bail out if device has not enough eraseblocks

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=2f4478ccff7df845dc9c0f8996a96373122c4417
Commit:     2f4478ccff7df845dc9c0f8996a96373122c4417
Parent:     f99640dee209df4730f35a28b02693affd571ad5
Author:     Wolfram Sang <w.sang at pengutronix.de>
AuthorDate: Tue Nov 29 15:34:08 2011 +0100
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Mon Jan 9 18:12:42 2012 +0000

    mtd: tests: stresstest: bail out if device has not enough eraseblocks
    
    stresstest needs at least two eraseblocks. Bail out gracefully if that
    condition is not met. Fixes the following 'division by zero' OOPS:
    
    [  619.100000] mtd_stresstest: MTD device size 131072, eraseblock size 131072, page size 2048, count of eraseblocks 1, pages per eraseblock 64, OOB size 64
    [  619.120000] mtd_stresstest: scanning for bad eraseblocks
    [  619.120000] mtd_stresstest: scanned 1 eraseblocks, 0 are bad
    [  619.130000] mtd_stresstest: doing operations
    [  619.130000] mtd_stresstest: 0 operations done
    [  619.140000] Division by zero in kernel.
    ...
    
    caused by
    
            /* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
            eb %= (ebcnt - 1);
    
    Cc: stable at kernel.org
    Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/tests/mtd_stresstest.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/tests/mtd_stresstest.c b/drivers/mtd/tests/mtd_stresstest.c
index 52ffd91..811642f 100644
--- a/drivers/mtd/tests/mtd_stresstest.c
+++ b/drivers/mtd/tests/mtd_stresstest.c
@@ -284,6 +284,12 @@ static int __init mtd_stresstest_init(void)
 	       (unsigned long long)mtd->size, mtd->erasesize,
 	       pgsize, ebcnt, pgcnt, mtd->oobsize);
 
+	if (ebcnt < 2) {
+		printk(PRINT_PREF "error: need at least 2 eraseblocks\n");
+		err = -ENOSPC;
+		goto out_put_mtd;
+	}
+
 	/* Read or write up 2 eraseblocks at a time */
 	bufsize = mtd->erasesize * 2;
 
@@ -322,6 +328,7 @@ out:
 	kfree(bbt);
 	vfree(writebuf);
 	vfree(readbuf);
+out_put_mtd:
 	put_mtd_device(mtd);
 	if (err)
 		printk(PRINT_PREF "error %d occurred\n", err);