tree 579185b75cf968de132d6a2b0cd6d4fd21ff9670
parent 5fdc2abe39b76822e34e7029ca5f69fe4bea58d4
author Tony Breeds <tony@bakeyournoodle.com> 1173083414 -0800
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1173110271 -0800

[PATCH] Fix soft lockup with iSeries viocd driver

Fix soft lockup with iSeries viocd driver, caused by eventually calling
end_that_request_first() with nr_bytes 0.

Some versions of hald do an SG_IO ioctl on the viocd device which becomes a
request with hard_nr_sectors and hard_cur_sectors set to zero.  Passing zero
as the number of sectors to end_request() (which calls
end_that_request_first()) causes an infinite loop when the bio is being freed.

This patch makes sure that the zero is never passed.  It only requires some
number larger the the request size the terminate the loop.

The lockup is triggered by hald, interrogating the device.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>