Re: Does pci_alloc_consisent really need to zero memory?

[David S. Miller]

   From: Emmanuel Michon <[e-mail]>
   Date: 30 May 2002 13:05:26 +0200

   "David S. Miller" <[e-mail]> writes:
   
   > I'd rather see a patch to DMA-mapping.txt that specifies the memory
   > returned is zeroed out, as this is what every implementation appears
   > to do.
   
   What was the idea when writing the code that zeroes memory? It seems
   so useless.
   
Because 9 out of 10 drivers where I had to change virt_to_bus
into the portable pci_alloc_consistent were using get_free_pages()
which zeros things out for you.

I do actually remember that many of those instances in fact did
depend on the memory being zero'd for them, they weren't using the
"zero the pages too" variant instead of __get_free_pages()
gratuitously.