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authorZhang Yanfei <zhangyanfei@cn.fujitsu.com>2013-07-03 15:08:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 16:08:03 -0700
commita11edb59a05d8d5195419bd1fc28d82752324158 (patch)
tree1100e82327ee45c50a4f9c0e47df9e845dcf0706
parent266b7a021f7dcc4d4531961a47f4ef74c3c4ab6b (diff)
/dev/oldmem: Remove the interface
/dev/oldmem provides the interface for us to access the "old memory" in the dump-capture kernel. Unfortunately, no one actually uses this interface. And this interface could actually cause some real problems if used on ia64 where the cached/uncached accesses are mixed. See the discussion from the link: https://lkml.org/lkml/2013/4/12/386. So Eric suggested that we should remove /dev/oldmem as an unused piece of code. [akpm@linux-foundation.org: mention /dev/oldmem obsolescence in devices.txt] Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Hansen <dave@sr71.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/devices.txt3
-rw-r--r--drivers/char/mem.c47
2 files changed, 1 insertions, 49 deletions
diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index b9015912bca6..23721d3be3e6 100644
--- a/Documentation/devices.txt
+++ b/Documentation/devices.txt
@@ -100,8 +100,7 @@ Your cooperation is appreciated.
10 = /dev/aio Asynchronous I/O notification interface
11 = /dev/kmsg Writes to this come out as printk's, reads
export the buffered printk records.
- 12 = /dev/oldmem Used by crashdump kernels to access
- the memory of the kernel that crashed.
+ 12 = /dev/oldmem OBSOLETE - replaced by /proc/vmcore
1 block RAM disk
0 = /dev/ram0 First RAM disk
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 2ca6d7844ad9..f895a8c8a244 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -21,7 +21,6 @@
#include <linux/ptrace.h>
#include <linux/device.h>
#include <linux/highmem.h>
-#include <linux/crash_dump.h>
#include <linux/backing-dev.h>
#include <linux/bootmem.h>
#include <linux/splice.h>
@@ -357,40 +356,6 @@ static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
}
#endif
-#ifdef CONFIG_CRASH_DUMP
-/*
- * Read memory corresponding to the old kernel.
- */
-static ssize_t read_oldmem(struct file *file, char __user *buf,
- size_t count, loff_t *ppos)
-{
- unsigned long pfn, offset;
- size_t read = 0, csize;
- int rc = 0;
-
- while (count) {
- pfn = *ppos / PAGE_SIZE;
- if (pfn > saved_max_pfn)
- return read;
-
- offset = (unsigned long)(*ppos % PAGE_SIZE);
- if (count > PAGE_SIZE - offset)
- csize = PAGE_SIZE - offset;
- else
- csize = count;
-
- rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
- if (rc < 0)
- return rc;
- buf += csize;
- *ppos += csize;
- read += csize;
- count -= csize;
- }
- return read;
-}
-#endif
-
#ifdef CONFIG_DEVKMEM
/*
* This function reads the *virtual* memory as seen by the kernel.
@@ -772,7 +737,6 @@ static int open_port(struct inode *inode, struct file *filp)
#define aio_write_zero aio_write_null
#define open_mem open_port
#define open_kmem open_mem
-#define open_oldmem open_mem
static const struct file_operations mem_fops = {
.llseek = memory_lseek,
@@ -837,14 +801,6 @@ static const struct file_operations full_fops = {
.write = write_full,
};
-#ifdef CONFIG_CRASH_DUMP
-static const struct file_operations oldmem_fops = {
- .read = read_oldmem,
- .open = open_oldmem,
- .llseek = default_llseek,
-};
-#endif
-
static const struct memdev {
const char *name;
umode_t mode;
@@ -866,9 +822,6 @@ static const struct memdev {
#ifdef CONFIG_PRINTK
[11] = { "kmsg", 0644, &kmsg_fops, NULL },
#endif
-#ifdef CONFIG_CRASH_DUMP
- [12] = { "oldmem", 0, &oldmem_fops, NULL },
-#endif
};
static int memory_open(struct inode *inode, struct file *filp)