path: root/block/cfq-iosched.c
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authorLinus Torvalds <torvalds@g5.osdl.org>2006-05-12 12:08:46 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-12 12:08:46 -0700
commit1a2acc9e9214699a99389e323e6686e9e0e2ca67 (patch)
tree8f8072ba0624ceb63ac0115a81d85435323fe79c /block/cfq-iosched.c
parentd8c3291c73b958243b33f8509d4507e76dafd055 (diff)
Revert "[BLOCK] Fix oops on removal of SD/MMC card"
This reverts commit 56cf6504fc1c0c221b82cebc16a444b684140fb7. Both Erik Mouw and Andrew Vasquez independently pinpointed this commit as causing problems, where the slab cache for a driver is never released (most obviously causing problems when immediately re-loading that driver, resulting in a "kmem_cache_create: duplicate cache <xyz>" message, but it can also cause other trouble). James Bottomley dug into it, and reports: "OK, here's the scoop. The problem patch adds a get of driverfs_dev in add_disk(), but doesn't put it again until disk_release() (which occurs on final put_disk() of the gendisk). However, in SCSI, the driverfs_dev is the sdev_gendev. That means there's a reference held on sdev_gendev until final disk put. Unfortunately, we use the driver model driver_remove to trigger del_gendisk (which removes the gendisk from visibility and decrements the refcount), so we've introduced an unbreakable deadlock in the reference counting with this. I suggest simply reversing this patch at the moment. If Russell and Jens can tell me what they're trying to do I'll see if there's another way to do it." so hereby the patch gets reverted, waiting for a better fix. Cc: Jens Axboe <axboe@suse.de> Cc: Russell King <rmk@arm.linux.org.uk> Cc: James Bottomley <James.Bottomley@SteelEye.com> Cc: Erik Mouw <erik@harddisk-recovery.com> Cc: Andrew Vasquez <andrew.vasquez@qlogic.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'block/cfq-iosched.c')
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