linux-kernel - [PATCH v4 2/3] powerpc/fadump: Use the correct VMCOREINFO_NOTE

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Message-Id: <1492688374-27903-2-git-send-email-xlpang@redhat.com>
Date:   Thu, 20 Apr 2017 19:39:33 +0800
From:   Xunlei Pang <xlpang@...hat.com>
To:     linux-kernel@...r.kernel.org, kexec@...ts.infradead.org
Cc:     akpm@...ux-foundation.org, Eric Biederman <ebiederm@...ssion.com>,
        Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
        Petr Tesarik <ptesarik@...e.cz>,
        Hari Bathini <hbathini@...ux.vnet.ibm.com>,
        Xunlei Pang <xlpang@...hat.com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>
Subject: [PATCH v4 2/3] powerpc/fadump: Use the correct VMCOREINFO_NOTE_SIZE for phdr

vmcoreinfo_max_size stands for the vmcoreinfo_data, the
correct one we should use is vmcoreinfo_note whose total
size is VMCOREINFO_NOTE_SIZE.

Like explained in commit 77019967f06b ("kdump: fix exported
size of vmcoreinfo note"), it should not affect the actual
function, but we better fix it, also this change should be
safe and backward compatible.

After this, we can get rid of variable vmcoreinfo_max_size,
let's use the corresponding macros directly, fewer variables
means more safety for vmcoreinfo operation.

Cc: Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@...ux.vnet.ibm.com>
Signed-off-by: Xunlei Pang <xlpang@...hat.com>
---
v3->v4:
-Rebased on the latest linux-next

 arch/powerpc/kernel/fadump.c | 3 +--
 include/linux/crash_core.h   | 1 -
 kernel/crash_core.c          | 3 +--
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 466569e..7bd6cd0 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -893,8 +893,7 @@ static int fadump_create_elfcore_headers(char *bufp)
 
 	phdr->p_paddr	= fadump_relocate(paddr_vmcoreinfo_note());
 	phdr->p_offset	= phdr->p_paddr;
-	phdr->p_memsz	= vmcoreinfo_max_size;
-	phdr->p_filesz	= vmcoreinfo_max_size;
+	phdr->p_memsz	= phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
 
 	/* Increment number of program headers. */
 	(elf->e_phnum)++;
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index ba283a2..7d6bc7b 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -55,7 +55,6 @@
 
 extern u32 *vmcoreinfo_note;
 extern size_t vmcoreinfo_size;
-extern size_t vmcoreinfo_max_size;
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len);
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 0321f04..43cdb00 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -16,7 +16,6 @@
 /* vmcoreinfo stuff */
 static unsigned char *vmcoreinfo_data;
 size_t vmcoreinfo_size;
-size_t vmcoreinfo_max_size = VMCOREINFO_BYTES;
 u32 *vmcoreinfo_note;
 
 /*
@@ -343,7 +342,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
 	r = vscnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
 
-	r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
+	r = min(r, VMCOREINFO_BYTES - vmcoreinfo_size);
 
 	memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
 
-- 
1.8.3.1