linux-kernel - [PATCH 08/17] Allow efi_free() to be called with size of 0, and do nothing in that case.

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Date:	Tue,  6 Aug 2013 20:45:04 -0700
From:	Roy Franz <roy.franz@...aro.org>
To:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, matt.fleming@...el.com,
	linux@....linux.org.uk
Cc:	leif.lindholm@...aro.org, dave.martin@....com,
	Roy Franz <roy.franz@...aro.org>
Subject: [PATCH 08/17] Allow efi_free() to be called with size of 0, and do nothing in that case.

Make efi_free() safely callable with size of 0, similar to free() being
callable with NULL pointers.
Remove size checks that this makes redundant.  This also avoids some
size checks in the ARM EFI stub code that will be added as well.

Signed-off-by: Roy Franz <roy.franz@...aro.org>
---
 arch/x86/boot/compressed/eboot.c       |    3 +--
 drivers/firmware/efi/efi-stub-helper.c |    3 +++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f44ef2f..bcfdcc2 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -537,8 +537,7 @@ struct boot_params *make_boot_params(void *handle, efi_system_table_t *_table)
 
 	return boot_params;
 fail2:
-	if (options_size)
-		efi_free(sys_table, options_size, hdr->cmd_line_ptr);
+	efi_free(sys_table, options_size, hdr->cmd_line_ptr);
 fail:
 	efi_free(sys_table, 0x4000, (unsigned long)boot_params);
 	return NULL;
diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index 8582650..bce0473 100644
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -253,6 +253,9 @@ static void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 {
 	unsigned long nr_pages;
 
+	if (!size)
+		return;
+
 	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 	efi_call_phys2(sys_table_arg->boottime->free_pages, addr, nr_pages);
 }
-- 
1.7.10.4

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