Messages in this thread |  | | | Subject | Re: [PATCH 01/17] MTD: create lockless versions of {get,put}_mtd_device This will be used to resolve deadlock in block translation layer. | | From | Peter Zijlstra <> | | Date | Tue, 09 Feb 2010 18:14:53 +0100 |
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On Tue, 2010-02-09 at 18:57 +0200, Maxim Levitsky wrote: > These functions can be used as long as we don't need access to global mtd table, but have > a pointer to the mtd device. > > Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> > --- > drivers/mtd/mtdcore.c | 60 ++++++++++++++++++++++++++++++---------------- > include/linux/mtd/mtd.h | 3 +- > 2 files changed, 41 insertions(+), 22 deletions(-)
> +int __get_mtd_device(struct mtd_info *mtd) > +{ > + int err; > + > + if (!try_module_get(mtd->owner)) > + return -ENODEV; > + > + if (mtd->get_device) { > + > + err = mtd->get_device(mtd); > + > + if (err) { > + module_put(mtd->owner); > + return err; > + } > + } > + mtd->usecount++; > + return 0; > }
> +void __put_mtd_device(struct mtd_info *mtd) > +{ > + --mtd->usecount; > + BUG_ON(mtd->usecount < 0); > + > if (mtd->put_device) > mtd->put_device(mtd); > > module_put(mtd->owner); > }
That's racy, use kref.
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