/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.
Besides, we used a global variable saved_max_pfn to let the capture kernel
know the amount of memory that the previous kernel used. And for almost all
architectures (except x86. In x86, saved_max_pfn is used by detect_calgary()),
the only user of this variable is the read_oldmem interface of /dev/oldmem, so
also remove the setting for saved_max_pfn in those architectures.
-v2:
Keep /dev/oldmem and its number 12 in case this number will get reused in the
future. And mark it obsolete since /dev/oldmem will be removed from kernel.
Zhang Yanfei (7):
/dev/oldmem: Remove this interface
Documentation/devices.txt: Mark /dev/oldmem obsolete
Documentation/kdump/kdump.txt: Remove /dev/oldmem description
mips: Remove savemaxmem parameter setup
powerpc: Remove savemaxmem parameter setup
ia64: Remove setting for saved_max_pfn
s390: Remove setting for saved_max_pfn
Documentation/devices.txt | 3 +-
Documentation/kdump/kdump.txt | 31 +++++--------------------
arch/ia64/kernel/efi.c | 5 ----
arch/mips/kernel/crash_dump.c | 10 --------
arch/powerpc/kernel/crash_dump.c | 10 --------
arch/s390/kernel/setup.c | 4 ---
drivers/char/mem.c | 47 --------------------------------------
7 files changed, 7 insertions(+), 103 deletions(-)
From: Zhang Yanfei <[email protected]>
/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.
Suggested-by: "Eric W. Biederman" <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Zhang Yanfei <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Andrew Morton <[email protected]>
---
drivers/char/mem.c | 47 -----------------------------------------------
1 files changed, 0 insertions(+), 47 deletions(-)
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 1ccbe94..bbe8ab4 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)
--
1.7.1
From: Zhang Yanfei <[email protected]>
Signed-off-by: Zhang Yanfei <[email protected]>
Cc: Dave Jones <[email protected]>
---
Documentation/devices.txt | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index 08f01e7..c8e4002 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
1 block RAM disk
0 = /dev/ram0 First RAM disk
--
1.7.1
From: Zhang Yanfei <[email protected]>
Signed-off-by: Zhang Yanfei <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Vivek Goyal <[email protected]>
---
Documentation/kdump/kdump.txt | 31 ++++++-------------------------
1 files changed, 6 insertions(+), 25 deletions(-)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 9c7fd98..bec123e 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -47,19 +47,12 @@ parameter. Optionally the size of the ELF header can also be passed
when using the elfcorehdr=[size[KMG]@]offset[KMG] syntax.
-With the dump-capture kernel, you can access the memory image, or "old
-memory," in two ways:
-
-- Through a /dev/oldmem device interface. A capture utility can read the
- device file and write out the memory in raw format. This is a raw dump
- of memory. Analysis and capture tools must be intelligent enough to
- determine where to look for the right information.
-
-- Through /proc/vmcore. This exports the dump as an ELF-format file that
- you can write out using file copy commands such as cp or scp. Further,
- you can use analysis tools such as the GNU Debugger (GDB) and the Crash
- tool to debug the dump file. This method ensures that the dump pages are
- correctly ordered.
+With the dump-capture kernel, you can access the memory image through
+/proc/vmcore. This exports the dump as an ELF-format file that you can
+write out using file copy commands such as cp or scp. Further, you can
+use analysis tools such as the GNU Debugger (GDB) and the Crash tool to
+debug the dump file. This method ensures that the dump pages are correctly
+ordered.
Setup and Installation
@@ -423,18 +416,6 @@ the following command:
cp /proc/vmcore <dump-file>
-You can also access dumped memory as a /dev/oldmem device for a linear
-and raw view. To create the device, use the following command:
-
- mknod /dev/oldmem c 1 12
-
-Use the dd command with suitable options for count, bs, and skip to
-access specific portions of the dump.
-
-To see the entire memory, use the following command:
-
- dd if=/dev/oldmem of=oldmem.001
-
Analysis
========
--
1.7.1
From: Zhang Yanfei <[email protected]>
saved_max_pfn is used to know the amount of memory that the previous
kernel used. And for powerpc, we set saved_max_pfn by passing the
kernel commandline parameter "savemaxmem=".
The only user of saved_max_pfn in mips is read_oldmem interface.
Since we have removed read_oldmem, so we don't need this parameter
anymore.
Signed-off-by: Zhang Yanfei <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Ralf Baechle <[email protected]>
---
arch/mips/kernel/crash_dump.c | 10 ----------
1 files changed, 0 insertions(+), 10 deletions(-)
diff --git a/arch/mips/kernel/crash_dump.c b/arch/mips/kernel/crash_dump.c
index 3be9e7b..f291cf9 100644
--- a/arch/mips/kernel/crash_dump.c
+++ b/arch/mips/kernel/crash_dump.c
@@ -4,16 +4,6 @@
#include <asm/uaccess.h>
#include <linux/slab.h>
-static int __init parse_savemaxmem(char *p)
-{
- if (p)
- saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
-
- return 1;
-}
-__setup("savemaxmem=", parse_savemaxmem);
-
-
static void *kdump_buf_page;
/**
--
1.7.1
From: Zhang Yanfei <[email protected]>
saved_max_pfn is used to know the amount of memory that the previous
kernel used. And for powerpc, we set saved_max_pfn by passing the
kernel commandline parameter "savemaxmem=".
The only user of saved_max_pfn in powerpc is read_oldmem interface.
Since we have removed read_oldmem, we don't need this parameter anymore.
Signed-off-by: Zhang Yanfei <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
---
arch/powerpc/kernel/crash_dump.c | 10 ----------
1 files changed, 0 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
index 9ec3fe1..779a78c 100644
--- a/arch/powerpc/kernel/crash_dump.c
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -69,16 +69,6 @@ void __init setup_kdump_trampoline(void)
}
#endif /* CONFIG_NONSTATIC_KERNEL */
-static int __init parse_savemaxmem(char *p)
-{
- if (p)
- saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
-
- return 1;
-}
-__setup("savemaxmem=", parse_savemaxmem);
-
-
static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
--
1.7.1
From: Zhang Yanfei <[email protected]>
The only user of saved_max_pfn in ia64 is read_oldmem interface but we
have removed that interface, so saved_max_pfn is now unneeded in ia64,
and we needn't set it anymore.
Signed-off-by: Zhang Yanfei <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Matt Fleming <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Fenghua Yu <[email protected]>
---
arch/ia64/kernel/efi.c | 5 -----
1 files changed, 0 insertions(+), 5 deletions(-)
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index f034563..51bce59 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -1116,11 +1116,6 @@ efi_memmap_init(u64 *s, u64 *e)
if (!is_memory_available(md))
continue;
-#ifdef CONFIG_CRASH_DUMP
- /* saved_max_pfn should ignore max_addr= command line arg */
- if (saved_max_pfn < (efi_md_end(md) >> PAGE_SHIFT))
- saved_max_pfn = (efi_md_end(md) >> PAGE_SHIFT);
-#endif
/*
* Round ends inward to granule boundaries
* Give trimmings to uncached allocator
--
1.7.1
From: Zhang Yanfei <[email protected]>
The only user of saved_max_pfn in s390 is read_oldmem interface but we
have removed that interface, so saved_max_pfn is now unneeded in s390,
and we needn't set it anymore.
Signed-off-by: Zhang Yanfei <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Michael Holzheu <[email protected]>
---
arch/s390/kernel/setup.c | 4 ----
1 files changed, 0 insertions(+), 4 deletions(-)
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 0a49095..497451e 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -719,10 +719,6 @@ static void reserve_oldmem(void)
}
create_mem_hole(memory_chunk, OLDMEM_BASE, OLDMEM_SIZE);
create_mem_hole(memory_chunk, OLDMEM_SIZE, real_size - OLDMEM_SIZE);
- if (OLDMEM_BASE + OLDMEM_SIZE == real_size)
- saved_max_pfn = PFN_DOWN(OLDMEM_BASE) - 1;
- else
- saved_max_pfn = PFN_DOWN(real_size) - 1;
#endif
}
--
1.7.1
(2013/05/26 15:36), Zhang Yanfei wrote:
> From: Zhang Yanfei <[email protected]>
>
> Signed-off-by: Zhang Yanfei <[email protected]>
> Cc: Dave Jones <[email protected]>
> ---
> Documentation/devices.txt | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
> index 08f01e7..c8e4002 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
>
> 1 block RAM disk
> 0 = /dev/ram0 First RAM disk
>
This is the new patch. Looking at other parts of devices.txt, obsolete is
sometimes used together with unused. I guess obsolete means this is old interface so
don't use it as much as possible and unused means this is not used at all now.
You remove old memory interface completely in this patch set, so is it better to add
unused, too?
--
Thanks.
HATAYAMA, Daisuke
于 2013年05月27日 09:46, HATAYAMA Daisuke 写道:
> (2013/05/26 15:36), Zhang Yanfei wrote:
>> From: Zhang Yanfei <[email protected]>
>>
>> Signed-off-by: Zhang Yanfei <[email protected]>
>> Cc: Dave Jones <[email protected]>
>> ---
>> Documentation/devices.txt | 3 +--
>> 1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
>> index 08f01e7..c8e4002 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
>>
>> 1 block RAM disk
>> 0 = /dev/ram0 First RAM disk
>>
>
> This is the new patch. Looking at other parts of devices.txt, obsolete is
> sometimes used together with unused. I guess obsolete means this is old interface so
> don't use it as much as possible and unused means this is not used at all now.
> You remove old memory interface completely in this patch set, so is it better to add
> unused, too?
>
Does obsolete also mean "not used anymore"? I don't know. I think we can wait for some native
English speakers to comment on this.
Thanks
Zhang
(2013/05/27 10:54), Zhang Yanfei wrote:
> 于 2013年05月27日 09:46, HATAYAMA Daisuke 写道:
>> (2013/05/26 15:36), Zhang Yanfei wrote:
>>> From: Zhang Yanfei <[email protected]>
>>>
>>> Signed-off-by: Zhang Yanfei <[email protected]>
>>> Cc: Dave Jones <[email protected]>
>>> ---
>>> Documentation/devices.txt | 3 +--
>>> 1 files changed, 1 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
>>> index 08f01e7..c8e4002 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
>>>
>>> 1 block RAM disk
>>> 0 = /dev/ram0 First RAM disk
>>>
>>
>> This is the new patch. Looking at other parts of devices.txt, obsolete is
>> sometimes used together with unused. I guess obsolete means this is old interface so
>> don't use it as much as possible and unused means this is not used at all now.
>> You remove old memory interface completely in this patch set, so is it better to add
>> unused, too?
>>
>
> Does obsolete also mean "not used anymore"? I don't know. I think we can wait for some native
> English speakers to comment on this.
>
Yes. To be honest, I'm still suspecting "unused" doesn't include meaning of "removed"...
--
Thanks.
HATAYAMA, Daisuke
On 05/26/2013 08:54:19 PM, Zhang Yanfei wrote:
> 于 2013年05月27日 09:46, HATAYAMA Daisuke 写道:
> > (2013/05/26 15:36), Zhang Yanfei wrote:
> >> From: Zhang Yanfei <[email protected]>
> >>
> >> Signed-off-by: Zhang Yanfei <[email protected]>
> >> Cc: Dave Jones <[email protected]>
> >> ---
> >> Documentation/devices.txt | 3 +--
> >> 1 files changed, 1 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
> >> index 08f01e7..c8e4002 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
> >>
> >> 1 block RAM disk
> >> 0 = /dev/ram0 First RAM disk
> >>
> >
> > This is the new patch. Looking at other parts of devices.txt,
> obsolete is
> > sometimes used together with unused. I guess obsolete means this is
> old interface so
> > don't use it as much as possible and unused means this is not used
> at all now.
> > You remove old memory interface completely in this patch set, so is
> it better to add
> > unused, too?
> >
>
> Does obsolete also mean "not used anymore"? I don't know. I think we
> can wait for some native
> English speakers to comment on this.
Obsolete implies that it shouldn't be used anymore. There are
exceptions to everything, of course...
(Unused means nothing is using it. If there's still code using it, it's
not unused. So yeah unused would imply removed.)
Rob-
On 05/28/2013 02:17 PM, Rob Landley wrote:
> On 05/26/2013 08:54:19 PM, Zhang Yanfei wrote:
>> 于 2013年05月27日 09:46, HATAYAMA Daisuke 写道:
>> > (2013/05/26 15:36), Zhang Yanfei wrote:
>> >> From: Zhang Yanfei <[email protected]>
>> >>
>> >> Signed-off-by: Zhang Yanfei <[email protected]>
>> >> Cc: Dave Jones <[email protected]>
>> >> ---
>> >> Documentation/devices.txt | 3 +--
>> >> 1 files changed, 1 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
>> >> index 08f01e7..c8e4002 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
>> >>
>> >> 1 block RAM disk
>> >> 0 = /dev/ram0 First RAM disk
>> >>
>> >
>> > This is the new patch. Looking at other parts of devices.txt, obsolete is
>> > sometimes used together with unused. I guess obsolete means this is old interface so
>> > don't use it as much as possible and unused means this is not used at all now.
>> > You remove old memory interface completely in this patch set, so is it better to add
>> > unused, too?
>> >
>>
>> Does obsolete also mean "not used anymore"? I don't know. I think we can wait for some native
>> English speakers to comment on this.
>
> Obsolete implies that it shouldn't be used anymore. There are exceptions to everything, of course...
>
> (Unused means nothing is using it. If there's still code using it, it's not unused. So yeah unused would imply removed.)
>
So, could I just use UNSED to replace OBSOLETE here? Or use "OBSOLETE/UNUSED"?
--
Thanks.
Zhang Yanfei
On 05/28/2013 01:25:25 AM, Zhang Yanfei wrote:
> On 05/28/2013 02:17 PM, Rob Landley wrote:
> > On 05/26/2013 08:54:19 PM, Zhang Yanfei wrote:
> >> 于 2013年05月27日 09:46, HATAYAMA Daisuke 写道:
> >> > (2013/05/26 15:36), Zhang Yanfei wrote:
> >> >> From: Zhang Yanfei <[email protected]>
> >> >>
> >> >> Signed-off-by: Zhang Yanfei <[email protected]>
> >> >> Cc: Dave Jones <[email protected]>
> >> >> ---
> >> >> Documentation/devices.txt | 3 +--
> >> >> 1 files changed, 1 insertions(+), 2 deletions(-)
> >> >>
> >> >> diff --git a/Documentation/devices.txt
> b/Documentation/devices.txt
> >> >> index 08f01e7..c8e4002 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
> >> >>
> >> >> 1 block RAM disk
> >> >> 0 = /dev/ram0 First RAM disk
> >> >>
> >> >
> >> > This is the new patch. Looking at other parts of devices.txt,
> obsolete is
> >> > sometimes used together with unused. I guess obsolete means this
> is old interface so
> >> > don't use it as much as possible and unused means this is not
> used at all now.
> >> > You remove old memory interface completely in this patch set, so
> is it better to add
> >> > unused, too?
> >> >
> >>
> >> Does obsolete also mean "not used anymore"? I don't know. I think
> we can wait for some native
> >> English speakers to comment on this.
> >
> > Obsolete implies that it shouldn't be used anymore. There are
> exceptions to everything, of course...
> >
> > (Unused means nothing is using it. If there's still code using it,
> it's not unused. So yeah unused would imply removed.)
> >
>
> So, could I just use UNSED to replace OBSOLETE here? Or use
> "OBSOLETE/UNUSED"?
Obsolete is fine.
Obsolete means it was used at some point, and thus reusing it might
confuse or conflcit with legacy software. Unused could just mean that
we left a gap for some reason, it doesn't imply it ever was used.
Explicitly documenting "unused" is kind of silly: all the ones we
_don't_ document are presumably unused. Obsolete carries with it a very
mild warning about legacy software, which is presumably why we still
bother to mention it at all instead of just removing the entry.
(Then again the point was that nothing ever used this interface in the
first place. Personally I'd just have removed the entry...)
Rob-
On 05/28/2013 10:26 AM, Rob Landley wrote:
>>
>> So, could I just use UNSED to replace OBSOLETE here? Or use
>> "OBSOLETE/UNUSED"?
>
> Obsolete is fine.
>
> Obsolete means it was used at some point, and thus reusing it might
> confuse or conflcit with legacy software. Unused could just mean that we
> left a gap for some reason, it doesn't imply it ever was used.
>
> Explicitly documenting "unused" is kind of silly: all the ones we
> _don't_ document are presumably unused. Obsolete carries with it a very
> mild warning about legacy software, which is presumably why we still
> bother to mention it at all instead of just removing the entry.
>
> (Then again the point was that nothing ever used this interface in the
> first place. Personally I'd just have removed the entry...)
>
"Obsolete" in this specific context means that the reservation is
obsolete, but was used in kernels past, therefore the name and number
should not be reused to prevent old software from misbehaving.
-hpa
Zhang Yanfei <[email protected]> writes:
> From: Zhang Yanfei <[email protected]>
>
> Signed-off-by: Zhang Yanfei <[email protected]>
> Cc: Dave Jones <[email protected]>
> ---
> Documentation/devices.txt | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
> index 08f01e7..c8e4002 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
Let me suggest the slightly better.
+ 12 = /dev/oldmem OBSOLETE - replaced by /proc/vmcore
Pointing to people to /proc/vmcore should help anyone who is trying to
understand what is going on.
> 1 block RAM disk
> 0 = /dev/ram0 First RAM disk
On 05/29/2013 06:29 AM, Eric W. Biederman wrote:
> Zhang Yanfei <[email protected]> writes:
>
>> From: Zhang Yanfei <[email protected]>
>>
>> Signed-off-by: Zhang Yanfei <[email protected]>
>> Cc: Dave Jones <[email protected]>
>> ---
>> Documentation/devices.txt | 3 +--
>> 1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devices.txt b/Documentation/devices.txt
>> index 08f01e7..c8e4002 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
>
> Let me suggest the slightly better.
>
> + 12 = /dev/oldmem OBSOLETE - replaced by /proc/vmcore
>
> Pointing to people to /proc/vmcore should help anyone who is trying to
> understand what is going on.
Makes sense to me. Updated patch below:
-----------------------------------
>From d2f7baf2aba86069f941f32669a22dbd99082614 Mon Sep 17 00:00:00 2001
From: Zhang Yanfei <[email protected]>
Date: Wed, 29 May 2013 15:44:09 +0800
Subject: [PATCH] Documentation/devices.txt: Mark /dev/oldmem obsolete
Signed-off-by: Zhang Yanfei <[email protected]>
---
Documentation/devices.txt | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index 08f01e7..315455a 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
--
1.7.1