Copy the description of v3 cover letter from Willy:
===
For some reason several people have been sending bad patches to fix
compiler warnings in vmcore recently. Here's how it should be done.
Compile-tested only on x86. As noted in the first patch, s390 should
take this conversion a bit further, but I'm not inclined to do that
work myself.
This series resends Willy's v3 patches which includes patch 1~3, and
append one patch to clean up the open code pointed out by Al.
Al's concerns to v3 patches and my reply after investigation:
https://lore.kernel.org/all/YhiTN0MORoQmFFkO@MiWiFi-R3L-srv/T/#u
Willy's v3 patchset:
[PATCH v3 0/3] Convert vmcore to use an iov_iter
https://lore.kernel.org/all/[email protected]/T/#u
Changelog:
===
v4:
- Append one patch to replace the open code with iov_iter_count().
This is suggested by Al.
- Fix a indentation error by replacing space with tab in
arch/sh/kernel/crash_dump.c of patch 1 reported by checkpatch. The
rest of patch 1~3 are untouched.
- Add Christopy's Reviewed-by and my Acked-by for patch 1~3.
v3:
- Send the correct patches this time
v2:
- Removed unnecessary kernel-doc
- Included uio.h to fix compilation problems
- Made read_from_oldmem_iter static to avoid compile warnings during the
conversion
- Use iov_iter_truncate() (Christoph)
Baoquan He (1):
fs/proc/vmcore: Use iov_iter_count()
Matthew Wilcox (Oracle) (3):
vmcore: Convert copy_oldmem_page() to take an iov_iter
vmcore: Convert __read_vmcore to use an iov_iter
vmcore: Convert read_from_oldmem() to take an iov_iter
arch/arm/kernel/crash_dump.c | 27 +------
arch/arm64/kernel/crash_dump.c | 29 +------
arch/ia64/kernel/crash_dump.c | 32 +-------
arch/mips/kernel/crash_dump.c | 27 +------
arch/powerpc/kernel/crash_dump.c | 35 ++-------
arch/riscv/kernel/crash_dump.c | 26 +------
arch/s390/kernel/crash_dump.c | 13 ++--
arch/sh/kernel/crash_dump.c | 29 ++-----
arch/x86/kernel/crash_dump_32.c | 29 +------
arch/x86/kernel/crash_dump_64.c | 48 ++++--------
fs/proc/vmcore.c | 130 +++++++++++++------------------
include/linux/crash_dump.h | 19 ++---
12 files changed, 123 insertions(+), 321 deletions(-)
--
2.34.1
From: "Matthew Wilcox (Oracle)" <[email protected]>
Remove the read_from_oldmem() wrapper introduced earlier and convert
all the remaining callers to pass an iov_iter.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Acked-by: Baoquan He <[email protected]>
---
arch/x86/kernel/crash_dump_64.c | 7 +++++-
fs/proc/vmcore.c | 40 +++++++++++++--------------------
include/linux/crash_dump.h | 10 ++++-----
3 files changed, 25 insertions(+), 32 deletions(-)
diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index f922d51c9d1f..0fa87648e55c 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -55,6 +55,11 @@ ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0,
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos,
cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));
}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index cebf49160ea5..4cbb8db7c507 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -127,7 +127,7 @@ static int open_vmcore(struct inode *inode, struct file *file)
}
/* Reads a page from the oldmem device from given offset. */
-static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count,
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
u64 *ppos, bool encrypted)
{
unsigned long pfn, offset;
@@ -175,27 +175,6 @@ static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count,
return read;
}
-ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted)
-{
- struct iov_iter iter;
- struct iovec iov;
- struct kvec kvec;
-
- if (userbuf) {
- iov.iov_base = (__force void __user *)buf;
- iov.iov_len = count;
- iov_iter_init(&iter, READ, &iov, 1, count);
- } else {
- kvec.iov_base = buf;
- kvec.iov_len = count;
- iov_iter_kvec(&iter, READ, &kvec, 1, count);
- }
-
- return read_from_oldmem_iter(&iter, count, ppos, encrypted);
-}
-
/*
* Architectures may override this function to allocate ELF header in 2nd kernel
*/
@@ -215,7 +194,12 @@ void __weak elfcorehdr_free(unsigned long long addr)
*/
ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, false);
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos, false);
}
/*
@@ -223,7 +207,13 @@ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
*/
ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos,
+ cc_platform_has(CC_ATTR_MEM_ENCRYPT));
}
/*
@@ -398,7 +388,7 @@ static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
m->offset + m->size - *fpos,
iter->count);
start = m->paddr + *fpos - m->offset;
- tmp = read_from_oldmem_iter(iter, tsz, &start,
+ tmp = read_from_oldmem(iter, tsz, &start,
cc_platform_has(CC_ATTR_MEM_ENCRYPT));
if (tmp < 0)
return tmp;
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index a1cf7d5c03c7..0f3a656293b0 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -134,13 +134,11 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
#ifdef CONFIG_PROC_VMCORE
-ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted);
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+ u64 *ppos, bool encrypted);
#else
-static inline ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted)
+static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+ u64 *ppos, bool encrypted)
{
return -EOPNOTSUPP;
}
--
2.34.1
From: "Matthew Wilcox (Oracle)" <[email protected]>
This gets rid of copy_to() and let us use proc_read_iter() instead
of proc_read().
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Acked-by: Baoquan He <[email protected]>
---
fs/proc/vmcore.c | 81 +++++++++++++++++-------------------------------
1 file changed, 29 insertions(+), 52 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 7e7252e162c2..cebf49160ea5 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -246,22 +246,8 @@ ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter,
return copy_oldmem_page(iter, pfn, csize, offset);
}
-/*
- * Copy to either kernel or user space
- */
-static int copy_to(void *target, void *src, size_t size, int userbuf)
-{
- if (userbuf) {
- if (copy_to_user((char __user *) target, src, size))
- return -EFAULT;
- } else {
- memcpy(target, src, size);
- }
- return 0;
-}
-
#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
-static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
+static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size)
{
struct vmcoredd_node *dump;
u64 offset = 0;
@@ -274,14 +260,13 @@ static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
if (start < offset + dump->size) {
tsz = min(offset + (u64)dump->size - start, (u64)size);
buf = dump->buf + start - offset;
- if (copy_to(dst, buf, tsz, userbuf)) {
+ if (copy_to_iter(buf, tsz, iter) < tsz) {
ret = -EFAULT;
goto out_unlock;
}
size -= tsz;
start += tsz;
- dst += tsz;
/* Leave now if buffer filled already */
if (!size)
@@ -337,33 +322,28 @@ static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
/* Read from the ELF header and then the crash dump. On error, negative value is
* returned otherwise number of bytes read are returned.
*/
-static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
- int userbuf)
+static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
{
ssize_t acc = 0, tmp;
size_t tsz;
u64 start;
struct vmcore *m = NULL;
- if (buflen == 0 || *fpos >= vmcore_size)
+ if (iter->count == 0 || *fpos >= vmcore_size)
return 0;
- /* trim buflen to not go beyond EOF */
- if (buflen > vmcore_size - *fpos)
- buflen = vmcore_size - *fpos;
+ iov_iter_truncate(iter, vmcore_size - *fpos);
/* Read ELF core header */
if (*fpos < elfcorebuf_sz) {
- tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
- if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
+ tsz = min(elfcorebuf_sz - (size_t)*fpos, iter->count);
+ if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz)
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (iter->count == 0)
return acc;
}
@@ -384,35 +364,31 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
/* Read device dumps */
if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
- (size_t)*fpos, buflen);
+ (size_t)*fpos, iter->count);
start = *fpos - elfcorebuf_sz;
- if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
+ if (vmcoredd_copy_dumps(iter, start, tsz))
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (!buflen)
+ if (!iter->count)
return acc;
}
#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
/* Read remaining elf notes */
- tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
+ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, iter->count);
kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
- if (copy_to(buffer, kaddr, tsz, userbuf))
+ if (copy_to_iter(kaddr, tsz, iter) < tsz)
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (iter->count == 0)
return acc;
}
@@ -420,19 +396,17 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
if (*fpos < m->offset + m->size) {
tsz = (size_t)min_t(unsigned long long,
m->offset + m->size - *fpos,
- buflen);
+ iter->count);
start = m->paddr + *fpos - m->offset;
- tmp = read_from_oldmem(buffer, tsz, &start,
- userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+ tmp = read_from_oldmem_iter(iter, tsz, &start,
+ cc_platform_has(CC_ATTR_MEM_ENCRYPT));
if (tmp < 0)
return tmp;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (iter->count == 0)
return acc;
}
}
@@ -440,15 +414,14 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
return acc;
}
-static ssize_t read_vmcore(struct file *file, char __user *buffer,
- size_t buflen, loff_t *fpos)
+static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter)
{
- return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
+ return __read_vmcore(iter, &iocb->ki_pos);
}
/*
* The vmcore fault handler uses the page cache and fills data using the
- * standard __vmcore_read() function.
+ * standard __read_vmcore() function.
*
* On s390 the fault handler is used for memory regions that can't be mapped
* directly with remap_pfn_range().
@@ -458,9 +431,10 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
#ifdef CONFIG_S390
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
pgoff_t index = vmf->pgoff;
+ struct iov_iter iter;
+ struct kvec kvec;
struct page *page;
loff_t offset;
- char *buf;
int rc;
page = find_or_create_page(mapping, index, GFP_KERNEL);
@@ -468,8 +442,11 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
return VM_FAULT_OOM;
if (!PageUptodate(page)) {
offset = (loff_t) index << PAGE_SHIFT;
- buf = __va((page_to_pfn(page) << PAGE_SHIFT));
- rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
+ kvec.iov_base = page_address(page);
+ kvec.iov_len = PAGE_SIZE;
+ iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE);
+
+ rc = __read_vmcore(&iter, &offset);
if (rc < 0) {
unlock_page(page);
put_page(page);
@@ -719,7 +696,7 @@ static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
static const struct proc_ops vmcore_proc_ops = {
.proc_open = open_vmcore,
- .proc_read = read_vmcore,
+ .proc_read_iter = read_vmcore,
.proc_lseek = default_llseek,
.proc_mmap = mmap_vmcore,
};
--
2.34.1
Forgot adding Andrew to CC, add him.
On 03/18/22 at 05:37pm, Baoquan He wrote:
> Copy the description of v3 cover letter from Willy:
> ===
> For some reason several people have been sending bad patches to fix
> compiler warnings in vmcore recently. Here's how it should be done.
> Compile-tested only on x86. As noted in the first patch, s390 should
> take this conversion a bit further, but I'm not inclined to do that
> work myself.
>
> This series resends Willy's v3 patches which includes patch 1~3, and
> append one patch to clean up the open code pointed out by Al.
>
> Al's concerns to v3 patches and my reply after investigation:
> https://lore.kernel.org/all/YhiTN0MORoQmFFkO@MiWiFi-R3L-srv/T/#u
>
> Willy's v3 patchset:
> [PATCH v3 0/3] Convert vmcore to use an iov_iter
> https://lore.kernel.org/all/[email protected]/T/#u
>
> Changelog:
> ===
> v4:
> - Append one patch to replace the open code with iov_iter_count().
> This is suggested by Al.
> - Fix a indentation error by replacing space with tab in
> arch/sh/kernel/crash_dump.c of patch 1 reported by checkpatch. The
> rest of patch 1~3 are untouched.
> - Add Christopy's Reviewed-by and my Acked-by for patch 1~3.
> v3:
> - Send the correct patches this time
> v2:
> - Removed unnecessary kernel-doc
> - Included uio.h to fix compilation problems
> - Made read_from_oldmem_iter static to avoid compile warnings during the
> conversion
> - Use iov_iter_truncate() (Christoph)
>
>
>
> Baoquan He (1):
> fs/proc/vmcore: Use iov_iter_count()
>
> Matthew Wilcox (Oracle) (3):
> vmcore: Convert copy_oldmem_page() to take an iov_iter
> vmcore: Convert __read_vmcore to use an iov_iter
> vmcore: Convert read_from_oldmem() to take an iov_iter
>
> arch/arm/kernel/crash_dump.c | 27 +------
> arch/arm64/kernel/crash_dump.c | 29 +------
> arch/ia64/kernel/crash_dump.c | 32 +-------
> arch/mips/kernel/crash_dump.c | 27 +------
> arch/powerpc/kernel/crash_dump.c | 35 ++-------
> arch/riscv/kernel/crash_dump.c | 26 +------
> arch/s390/kernel/crash_dump.c | 13 ++--
> arch/sh/kernel/crash_dump.c | 29 ++-----
> arch/x86/kernel/crash_dump_32.c | 29 +------
> arch/x86/kernel/crash_dump_64.c | 48 ++++--------
> fs/proc/vmcore.c | 130 +++++++++++++------------------
> include/linux/crash_dump.h | 19 ++---
> 12 files changed, 123 insertions(+), 321 deletions(-)
>
> --
> 2.34.1
>
Hi Andrew,
On 03/18/22 at 05:37pm, Baoquan He wrote:
> Copy the description of v3 cover letter from Willy:
Could you pick this series into your tree? I reviewed the patches 1~3
and tested the whole patchset, no issue found.
Thanks
Baoquan
> ===
> For some reason several people have been sending bad patches to fix
> compiler warnings in vmcore recently. Here's how it should be done.
> Compile-tested only on x86. As noted in the first patch, s390 should
> take this conversion a bit further, but I'm not inclined to do that
> work myself.
>
> This series resends Willy's v3 patches which includes patch 1~3, and
> append one patch to clean up the open code pointed out by Al.
>
> Al's concerns to v3 patches and my reply after investigation:
> https://lore.kernel.org/all/YhiTN0MORoQmFFkO@MiWiFi-R3L-srv/T/#u
>
> Willy's v3 patchset:
> [PATCH v3 0/3] Convert vmcore to use an iov_iter
> https://lore.kernel.org/all/[email protected]/T/#u
>
> Changelog:
> ===
> v4:
> - Append one patch to replace the open code with iov_iter_count().
> This is suggested by Al.
> - Fix a indentation error by replacing space with tab in
> arch/sh/kernel/crash_dump.c of patch 1 reported by checkpatch. The
> rest of patch 1~3 are untouched.
> - Add Christopy's Reviewed-by and my Acked-by for patch 1~3.
> v3:
> - Send the correct patches this time
> v2:
> - Removed unnecessary kernel-doc
> - Included uio.h to fix compilation problems
> - Made read_from_oldmem_iter static to avoid compile warnings during the
> conversion
> - Use iov_iter_truncate() (Christoph)
>
>
>
> Baoquan He (1):
> fs/proc/vmcore: Use iov_iter_count()
>
> Matthew Wilcox (Oracle) (3):
> vmcore: Convert copy_oldmem_page() to take an iov_iter
> vmcore: Convert __read_vmcore to use an iov_iter
> vmcore: Convert read_from_oldmem() to take an iov_iter
>
> arch/arm/kernel/crash_dump.c | 27 +------
> arch/arm64/kernel/crash_dump.c | 29 +------
> arch/ia64/kernel/crash_dump.c | 32 +-------
> arch/mips/kernel/crash_dump.c | 27 +------
> arch/powerpc/kernel/crash_dump.c | 35 ++-------
> arch/riscv/kernel/crash_dump.c | 26 +------
> arch/s390/kernel/crash_dump.c | 13 ++--
> arch/sh/kernel/crash_dump.c | 29 ++-----
> arch/x86/kernel/crash_dump_32.c | 29 +------
> arch/x86/kernel/crash_dump_64.c | 48 ++++--------
> fs/proc/vmcore.c | 130 +++++++++++++------------------
> include/linux/crash_dump.h | 19 ++---
> 12 files changed, 123 insertions(+), 321 deletions(-)
>
> --
> 2.34.1
>
On Thu, 31 Mar 2022 15:36:39 +0100 Matthew Wilcox <[email protected]> wrote:
> On Thu, Mar 31, 2022 at 07:25:33PM +0800, Baoquan He wrote:
> > Hi Andrew,
> >
> > On 03/18/22 at 05:37pm, Baoquan He wrote:
> > > Copy the description of v3 cover letter from Willy:
> >
> > Could you pick this series into your tree? I reviewed the patches 1~3
> > and tested the whole patchset, no issue found.
>
> ... I'd fold patch 4 into patch 1,
I think so too, please. The addition then removal of a
read_from_oldmem() implementation is a bit odd.
> but yes, Andrew, please take these patches.
And against current -linus please. There have been some changes since
then (rcu stuff).
On Thu, Mar 31, 2022 at 07:25:33PM +0800, Baoquan He wrote:
> Hi Andrew,
>
> On 03/18/22 at 05:37pm, Baoquan He wrote:
> > Copy the description of v3 cover letter from Willy:
>
> Could you pick this series into your tree? I reviewed the patches 1~3
> and tested the whole patchset, no issue found.
... I'd fold patch 4 into patch 1, but yes, Andrew, please take these
patches.
On 03/31/22 at 05:14pm, Andrew Morton wrote:
> On Thu, 31 Mar 2022 15:36:39 +0100 Matthew Wilcox <[email protected]> wrote:
>
> > On Thu, Mar 31, 2022 at 07:25:33PM +0800, Baoquan He wrote:
> > > Hi Andrew,
> > >
> > > On 03/18/22 at 05:37pm, Baoquan He wrote:
> > > > Copy the description of v3 cover letter from Willy:
> > >
> > > Could you pick this series into your tree? I reviewed the patches 1~3
> > > and tested the whole patchset, no issue found.
> >
> > ... I'd fold patch 4 into patch 1,
>
> I think so too, please. The addition then removal of a
> read_from_oldmem() implementation is a bit odd.
>
> > but yes, Andrew, please take these patches.
>
> And against current -linus please. There have been some changes since
> then (rcu stuff).
OK, I will fold 1 to 4, and send v5 based on linus's tree.