Messages in this thread | | | From | Kevin Corry <> | Subject | Re: [dm-devel] Re: [2.6 patch] dm: remove unused functions (fwd) | Date | Wed, 1 Dec 2004 08:41:06 -0600 |
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On Tuesday 30 November 2004 5:05 pm, Alasdair G Kergon wrote: > On Mon, Nov 29, 2004 at 03:29:40AM +0100, Adrian Bunk wrote: > > Please apply or comment on it. > > Please check *why* the functions aren't used first. > > e.g. An alloc function with a corresponding free that > never gets called suggests a leak to me...
That one isn't a leak (referring to "kmem_cache_t *exception_cache" in dm-snap.c). Items are allocated from this cache using alloc_exception(). This can happen either when an existing snapshot is activated and it's exception table is read from disk into an in-memory hash-table, or when a copy-on-write completes and a new exception is added to this hash-table. As long as the snapshot is active, this hash-table remains in memory and items cannot be removed from it. When the snapshot is deactivated, we call exit_exception_table() and pass it a pointer to this hash-table and exception_cache. This routine calls kmem_cache_free() directly instead of using the free_exception() routine. The reason it doesn't use free_exception() is that exit_exception_table() is used to tear down two different but somewhat similar hash-tables, each of which uses a different kmem_cache_t.
So, it may be nice to keep the symmetric routines defined (alloc_exception() and free_exception()), but Adrian is correct in that the later is not being used, and it really can't be used without some more significant code changes.
As for bs_bio_init(), it can be safely removed. It was just a duplicate of bio_init() from fs/bio.c. The use of that call in dm-io.c was changed to use bio_init(), but apparently the routine itself was never removed.
-- Kevin Corry kevcorry@us.ibm.com http://evms.sourceforge.net/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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