alloc_disk in linux-2.5.45/drivers/block/genhd.c calls
rand_initialize_disk, which can set disk->random to NULL on kmalloc
failure. disk_release does a kfree(disk->random) without checking.
I could add an "if(disk->random == NULL)" to disk_release,
memory allocation policy for disk->random does not need to be split
between genhd.c and and random.c, and disk->random is so small that
there is really no benefit to kmalloc'ing it.
More importantly, I want to reduce memory allocation error
branches (or, worse, lack of branches where they are needed as this
case as this case illustrates), especially because I'd eventually like
to have a variant of alloc_disk that doesn't do the kmalloc, so I can
embed the struct gendisk and have a gendisk initializer that doesn't
need an error branch (init_disk(disk, partitions_array,...), but
that's another matter).
So, here is a patch to embed disk->random. It is a net
deletion of ten lines. It also moves the declarations for
add_disk_randomness and rand_initialize_disk to <linux/random.h> where
the other add_foo_randomness and rand_initialize_foo routines are
declared.
--
Adam J. Richter __ ______________ 575 Oroville Road
adam@yggdrasil.com \ / Milpitas, California 95035
+1 408 309-6081 | g g d r a s i l United States of America
"Free Software For The Rest Of Us."
This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:34 EST