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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-02-01 22:06:58 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-02-03 11:31:04 +0100 |
| commit | ca0e30dcaa53a3fcb2dfdf74252d30bc40603eea (patch) | |
| tree | ff97b9475eaeca4fb8007dc1ba10836fe4f21373 /drivers/firmware | |
| parent | d3cac1f83c631b9fe5edaebcba49f6989bfff089 (diff) | |
| download | linux-ca0e30dcaa53a3fcb2dfdf74252d30bc40603eea.tar.gz linux-ca0e30dcaa53a3fcb2dfdf74252d30bc40603eea.tar.xz | |
efi: Add nonblocking option to efi_query_variable_store()
The function efi_query_variable_store() may be invoked by
efivar_entry_set_nonblocking(), which itself takes care to only
call a non-blocking version of the SetVariable() runtime
wrapper. However, efi_query_variable_store() may call the
SetVariable() wrapper directly, as well as the wrapper for
QueryVariableInfo(), both of which could deadlock in the same
way we are trying to prevent by calling
efivar_entry_set_nonblocking() in the first place.
So instead, modify efi_query_variable_store() to use the
non-blocking variants of QueryVariableInfo() (and give up rather
than free up space if the available space is below
EFI_MIN_RESERVE) if invoked with the 'nonblocking' argument set
to true.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1454364428-494-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/vars.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 70a0fb10517f..d2a49626a335 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -234,7 +234,18 @@ check_var_size(u32 attributes, unsigned long size) if (!fops->query_variable_store) return EFI_UNSUPPORTED; - return fops->query_variable_store(attributes, size); + return fops->query_variable_store(attributes, size, false); +} + +static efi_status_t +check_var_size_nonblocking(u32 attributes, unsigned long size) +{ + const struct efivar_operations *fops = __efivars->ops; + + if (!fops->query_variable_store) + return EFI_UNSUPPORTED; + + return fops->query_variable_store(attributes, size, true); } static int efi_status_to_err(efi_status_t status) @@ -615,7 +626,8 @@ efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, if (!spin_trylock_irqsave(&__efivars->lock, flags)) return -EBUSY; - status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); + status = check_var_size_nonblocking(attributes, + size + ucs2_strsize(name, 1024)); if (status != EFI_SUCCESS) { spin_unlock_irqrestore(&__efivars->lock, flags); return -ENOSPC; |