RE: [PATCH v2 3/3] efi: Add support for using efivars as a pstorebackend

From: Luck, Tony
Date: Tue Jun 07 2011 - 16:17:03 EST


+ efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+ if (efi_pstore_info.buf) {
+ efi_pstore_info.bufsize = 1024;
+ efi_pstore_info.data = efivars;
+ mutex_init(&efi_pstore_info.buf_mutex);
+ pstore_register(&efi_pstore_info);
+ }

I'd imagined #ifdef CONFIG_PSTORE around this (and the
efi_pstore_info definition) rather than providing stubs
for the !PSTORE case.

But your way works too.

You should avoid a memory leak with:

if (!pstore_register(&efi_pstore_info))
kfree(efi_pstore_info.buf);


I've also been thinking some more about how to handle a
system that has more than one pstore back-end available.
I still don't have any good ideas how to make use of more
than one backend - but it occurs to me that we may need
a way to let the user choose which to use (e.g. in the
unlikely event that a BIOS bug made one of ERST or EFI
unusable by pstore). The current "whoever registers first
gets to use it" now seems inadequate.

Perhaps a command line "pstore={backend}" might work, so
the user could specify pstore=efi to get your code, and
pstore=erst to get mine.


-Tony
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