LinuxLists.cc - [PATCH v3 0/3] Few bug fixes and Convert to pin_user

2020-07-12 03:32:02

Subject: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

This series contains few clean up, minor bug fixes and
Convert get_user_pages() to pin_user_pages().

I'm compile tested this, but unable to run-time test,
so any testing help is much appriciated.

v2:
Addressed few review comments and compile issue.
Patch[1/2] from v1 split into 2 in v2.
v3:
Address review comment. Add review tag.

Cc: John Hubbard <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Paul Durrant <[email protected]>

Souptick Joarder (3):
xen/privcmd: Corrected error handling path
xen/privcmd: Mark pages as dirty
xen/privcmd: Convert get_user_pages*() to pin_user_pages*()

drivers/xen/privcmd.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)

--
1.9.1

2020-07-12 03:32:13

by Souptick Joarder

[permalink] [raw]

Subject: [PATCH v3 1/3] xen/privcmd: Corrected error handling path

Previously, if lock_pages() end up partially mapping pages, it used
to return -ERRNO due to which unlock_pages() have to go through
each pages[i] till *nr_pages* to validate them. This can be avoided
by passing correct number of partially mapped pages & -ERRNO separately,
while returning from lock_pages() due to error.

With this fix unlock_pages() doesn't need to validate pages[i] till
*nr_pages* for error scenario and few condition checks can be ignored.

Signed-off-by: Souptick Joarder <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Paul Durrant <[email protected]>
---
drivers/xen/privcmd.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 5dfc59f..b001673 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -579,13 +579,13 @@ static long privcmd_ioctl_mmap_batch(

static int lock_pages(
struct privcmd_dm_op_buf kbufs[], unsigned int num,
- struct page *pages[], unsigned int nr_pages)
+ struct page *pages[], unsigned int nr_pages, unsigned int *pinned)
{
unsigned int i;

for (i = 0; i < num; i++) {
unsigned int requested;
- int pinned;
+ int page_count;

requested = DIV_ROUND_UP(
offset_in_page(kbufs[i].uptr) + kbufs[i].size,
@@ -593,14 +593,15 @@ static int lock_pages(
if (requested > nr_pages)
return -ENOSPC;

- pinned = get_user_pages_fast(
+ page_count = get_user_pages_fast(
(unsigned long) kbufs[i].uptr,
requested, FOLL_WRITE, pages);
- if (pinned < 0)
- return pinned;
+ if (page_count < 0)
+ return page_count;

- nr_pages -= pinned;
- pages += pinned;
+ *pinned += page_count;
+ nr_pages -= page_count;
+ pages += page_count;
}

return 0;
@@ -610,13 +611,8 @@ static void unlock_pages(struct page *pages[], unsigned int nr_pages)
{
unsigned int i;

- if (!pages)
- return;
-
- for (i = 0; i < nr_pages; i++) {
- if (pages[i])
- put_page(pages[i]);
- }
+ for (i = 0; i < nr_pages; i++)
+ put_page(pages[i]);
}

static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
@@ -629,6 +625,7 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
struct xen_dm_op_buf *xbufs = NULL;
unsigned int i;
long rc;
+ unsigned int pinned = 0;

if (copy_from_user(&kdata, udata, sizeof(kdata)))
return -EFAULT;
@@ -682,9 +679,11 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
goto out;
}

- rc = lock_pages(kbufs, kdata.num, pages, nr_pages);
- if (rc)
+ rc = lock_pages(kbufs, kdata.num, pages, nr_pages, &pinned);
+ if (rc < 0) {
+ nr_pages = pinned;
goto out;
+ }

for (i = 0; i < kdata.num; i++) {
set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr);
--
1.9.1

2020-07-12 03:35:14

by Souptick Joarder

[permalink] [raw]

Subject: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages() to pin_user_pages()

In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 5 as per document [1].

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/

Signed-off-by: Souptick Joarder <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Paul Durrant <[email protected]>
---
drivers/xen/privcmd.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 079d35b..63abe6c 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -593,7 +593,7 @@ static int lock_pages(
if (requested > nr_pages)
return -ENOSPC;

- page_count = get_user_pages_fast(
+ page_count = pin_user_pages_fast(
(unsigned long) kbufs[i].uptr,
requested, FOLL_WRITE, pages);
if (page_count < 0)
@@ -609,13 +609,7 @@ static int lock_pages(

static void unlock_pages(struct page *pages[], unsigned int nr_pages)
{
- unsigned int i;
-
- for (i = 0; i < nr_pages; i++) {
- if (!PageDirty(pages[i]))
- set_page_dirty_lock(pages[i]);
- put_page(pages[i]);
- }
+ unpin_user_pages_dirty_lock(pages, nr_pages, true);
}

static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
--
1.9.1

2020-07-12 03:35:58

by Souptick Joarder

[permalink] [raw]

Subject: [PATCH v3 2/3] xen/privcmd: Mark pages as dirty

pages need to be marked as dirty before unpinned it in
unlock_pages() which was oversight. This is fixed now.

Signed-off-by: Souptick Joarder <[email protected]>
Suggested-by: John Hubbard <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Paul Durrant <[email protected]>
---
drivers/xen/privcmd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index b001673..079d35b 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -611,8 +611,11 @@ static void unlock_pages(struct page *pages[], unsigned int nr_pages)
{
unsigned int i;

- for (i = 0; i < nr_pages; i++)
+ for (i = 0; i < nr_pages; i++) {
+ if (!PageDirty(pages[i]))
+ set_page_dirty_lock(pages[i]);
put_page(pages[i]);
+ }
}

static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
--
1.9.1

2020-07-13 08:09:08

by Paul Durrant

[permalink] [raw]

Subject: RE: [PATCH v3 1/3] xen/privcmd: Corrected error handling path

> -----Original Message-----
> From: Souptick Joarder <[email protected]>
> Sent: 12 July 2020 04:40
> To: [email protected]; [email protected]; [email protected]
> Cc: [email protected]; [email protected]; Souptick Joarder
> <[email protected]>; John Hubbard <[email protected]>; Paul Durrant <[email protected]>
> Subject: [PATCH v3 1/3] xen/privcmd: Corrected error handling path
>
> Previously, if lock_pages() end up partially mapping pages, it used
> to return -ERRNO due to which unlock_pages() have to go through
> each pages[i] till *nr_pages* to validate them. This can be avoided
> by passing correct number of partially mapped pages & -ERRNO separately,
> while returning from lock_pages() due to error.
>
> With this fix unlock_pages() doesn't need to validate pages[i] till
> *nr_pages* for error scenario and few condition checks can be ignored.
>
> Signed-off-by: Souptick Joarder <[email protected]>
> Reviewed-by: Juergen Gross <[email protected]>
> Cc: John Hubbard <[email protected]>
> Cc: Boris Ostrovsky <[email protected]>
> Cc: Paul Durrant <[email protected]>

Reviewed-by: Paul Durrant <[email protected]>

> ---
> drivers/xen/privcmd.c | 31 +++++++++++++++----------------
> 1 file changed, 15 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 5dfc59f..b001673 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -579,13 +579,13 @@ static long privcmd_ioctl_mmap_batch(
>
> static int lock_pages(
> struct privcmd_dm_op_buf kbufs[], unsigned int num,
> - struct page *pages[], unsigned int nr_pages)
> + struct page *pages[], unsigned int nr_pages, unsigned int *pinned)
> {
> unsigned int i;
>
> for (i = 0; i < num; i++) {
> unsigned int requested;
> - int pinned;
> + int page_count;
>
> requested = DIV_ROUND_UP(
> offset_in_page(kbufs[i].uptr) + kbufs[i].size,
> @@ -593,14 +593,15 @@ static int lock_pages(
> if (requested > nr_pages)
> return -ENOSPC;
>
> - pinned = get_user_pages_fast(
> + page_count = get_user_pages_fast(
> (unsigned long) kbufs[i].uptr,
> requested, FOLL_WRITE, pages);
> - if (pinned < 0)
> - return pinned;
> + if (page_count < 0)
> + return page_count;
>
> - nr_pages -= pinned;
> - pages += pinned;
> + *pinned += page_count;
> + nr_pages -= page_count;
> + pages += page_count;
> }
>
> return 0;
> @@ -610,13 +611,8 @@ static void unlock_pages(struct page *pages[], unsigned int nr_pages)
> {
> unsigned int i;
>
> - if (!pages)
> - return;
> -
> - for (i = 0; i < nr_pages; i++) {
> - if (pages[i])
> - put_page(pages[i]);
> - }
> + for (i = 0; i < nr_pages; i++)
> + put_page(pages[i]);
> }
>
> static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
> @@ -629,6 +625,7 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
> struct xen_dm_op_buf *xbufs = NULL;
> unsigned int i;
> long rc;
> + unsigned int pinned = 0;
>
> if (copy_from_user(&kdata, udata, sizeof(kdata)))
> return -EFAULT;
> @@ -682,9 +679,11 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
> goto out;
> }
>
> - rc = lock_pages(kbufs, kdata.num, pages, nr_pages);
> - if (rc)
> + rc = lock_pages(kbufs, kdata.num, pages, nr_pages, &pinned);
> + if (rc < 0) {
> + nr_pages = pinned;
> goto out;
> + }
>
> for (i = 0; i < kdata.num; i++) {
> set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr);
> --
> 1.9.1

2020-07-13 08:12:18

by Paul Durrant

[permalink] [raw]

Subject: RE: [PATCH v3 2/3] xen/privcmd: Mark pages as dirty

2020-07-13 08:13:07

by Paul Durrant

[permalink] [raw]

Subject: RE: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages() to pin_user_pages()

2020-07-28 07:13:38

by Souptick Joarder

[permalink] [raw]

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

Hi Boris,

On Sun, Jul 12, 2020 at 9:01 AM Souptick Joarder <[email protected]> wrote:
>
> This series contains few clean up, minor bug fixes and
> Convert get_user_pages() to pin_user_pages().
>
> I'm compile tested this, but unable to run-time test,
> so any testing help is much appriciated.
>
> v2:
> Addressed few review comments and compile issue.
> Patch[1/2] from v1 split into 2 in v2.
> v3:
> Address review comment. Add review tag.
>
> Cc: John Hubbard <[email protected]>
> Cc: Boris Ostrovsky <[email protected]>
> Cc: Paul Durrant <[email protected]>
>
> Souptick Joarder (3):
> xen/privcmd: Corrected error handling path
> xen/privcmd: Mark pages as dirty
> xen/privcmd: Convert get_user_pages*() to pin_user_pages*()

Does this series looks good to go for 5.9 ?

>
> drivers/xen/privcmd.c | 32 ++++++++++++++------------------
> 1 file changed, 14 insertions(+), 18 deletions(-)
>
> --
> 1.9.1
>

2020-07-28 07:39:09

by Juergen Gross

[permalink] [raw]

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

On 28.07.20 09:10, Souptick Joarder wrote:
> Hi Boris,
>
> On Sun, Jul 12, 2020 at 9:01 AM Souptick Joarder <[email protected]> wrote:
>>
>> This series contains few clean up, minor bug fixes and
>> Convert get_user_pages() to pin_user_pages().
>>
>> I'm compile tested this, but unable to run-time test,
>> so any testing help is much appriciated.
>>
>> v2:
>> Addressed few review comments and compile issue.
>> Patch[1/2] from v1 split into 2 in v2.
>> v3:
>> Address review comment. Add review tag.
>>
>> Cc: John Hubbard <[email protected]>
>> Cc: Boris Ostrovsky <[email protected]>
>> Cc: Paul Durrant <[email protected]>
>>
>> Souptick Joarder (3):
>> xen/privcmd: Corrected error handling path
>> xen/privcmd: Mark pages as dirty
>> xen/privcmd: Convert get_user_pages*() to pin_user_pages*()
>
> Does this series looks good to go for 5.9 ?

Yes. I already have it in my queue.

Juergen

2020-08-03 05:45:34

by Juergen Gross

[permalink] [raw]

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

On 12.07.20 05:39, Souptick Joarder wrote:
> This series contains few clean up, minor bug fixes and
> Convert get_user_pages() to pin_user_pages().
>
> I'm compile tested this, but unable to run-time test,
> so any testing help is much appriciated.
>
> v2:
> Addressed few review comments and compile issue.
> Patch[1/2] from v1 split into 2 in v2.
> v3:
> Address review comment. Add review tag.
>
> Cc: John Hubbard <[email protected]>
> Cc: Boris Ostrovsky <[email protected]>
> Cc: Paul Durrant <[email protected]>
>
> Souptick Joarder (3):
> xen/privcmd: Corrected error handling path
> xen/privcmd: Mark pages as dirty
> xen/privcmd: Convert get_user_pages*() to pin_user_pages*()
>
> drivers/xen/privcmd.c | 32 ++++++++++++++------------------
> 1 file changed, 14 insertions(+), 18 deletions(-)
>

Series pushed to xen/tip.git for-linus-5.9

Juergen

Subject: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

Subject: [PATCH v3 1/3] xen/privcmd: Corrected error handling path

Subject: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages*() to pin_user_pages*()

Subject: [PATCH v3 2/3] xen/privcmd: Mark pages as dirty

Subject: RE: [PATCH v3 1/3] xen/privcmd: Corrected error handling path

Subject: RE: [PATCH v3 2/3] xen/privcmd: Mark pages as dirty

Subject: RE: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages*() to pin_user_pages*()

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

Subject: Re: [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*()

Subject: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages() to pin_user_pages()

Subject: RE: [PATCH v3 3/3] xen/privcmd: Convert get_user_pages() to pin_user_pages()