Messages in this thread | | | Date | Wed, 06 Feb 2002 15:44:09 -0800 | From | Dave Hansen <> | Subject | [PATCH] Removal of big kernel lock from isdn drivers |
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I've been examining the continuing additions of the big kernel lock (BKL) to the 2.5 tree. I noticed that in 2.5.3, the ISDN subsystem added the BKL to several places. In response to this, I have written several patches to attempt removal of the BKL from the ISDN subsystem. I have little knowledge of the drivers themselves, so I would like some assistance from those of you who understand them better. I probably have an over-simplified view of the code, so my patches may be too simplistic. They're a bit big, so I've made them available here: http://www.sr71.net/ibm/isdn/
isdn.bkl-remove.ippp_lock.patch: http://www.sr71.net/ibm/isdn/isdn.bkl-remove.isdn_dev_sem.patch added ippp_lock to ippp_struct * It appeared that the BKL was being used to guard the file struct's private data field, which is a ippp_struct. I added a semaphore to that structure which can be locked instead of the BKL.
isdn.bkl-remove.hydsn_cards_sem.patch: http://www.sr71.net/ibm/isdn/isdn.bkl-remove.hydsn_cards_sem.patch adds rwsemaphore hydsn_cards_sem * hydsn_cards_sem guards the card_root list. It is a read/write semaphore which must be held for write when modifying the list.
isdn.bkl-remove.isdn_dev_rwsem.patch: http://www.sr71.net/ibm/isdn/isdn.bkl-remove.ppp_lock.patch * changes name of "dev" to "isdn_dev" - If there are going to be global variables, they can at least not have exceedingly generic names like "dev"! * adds global isdn_dev_rwsem - isdn_dev_rwsem must be held when manipulating "isdn_dev"
I know that these patches should probably be separate, but this is easier for me.
-- Dave Hansen haveblue@us.ibm.com
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