From: Souptick Joarder <jrdr.linux@gmail.com>
To: boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
Souptick Joarder <jrdr.linux@gmail.com>,
John Hubbard <jhubbard@nvidia.com>,
Paul Durrant <xadimgnik@gmail.com>
Subject: [PATCH v3 1/3] xen/privcmd: Corrected error handling path
Date: Sun, 12 Jul 2020 09:09:53 +0530 [thread overview]
Message-ID: <1594525195-28345-2-git-send-email-jrdr.linux@gmail.com> (raw)
In-Reply-To: <1594525195-28345-1-git-send-email-jrdr.linux@gmail.com>
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 <jrdr.linux@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Paul Durrant <xadimgnik@gmail.com>
---
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
next prev parent reply other threads:[~2020-07-12 3:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-12 3:39 [PATCH v3 0/3] Few bug fixes and Convert to pin_user_pages*() Souptick Joarder
2020-07-12 3:39 ` Souptick Joarder [this message]
2020-07-13 8:08 ` [PATCH v3 1/3] xen/privcmd: Corrected error handling path Paul Durrant
2020-07-12 3:39 ` [PATCH v3 2/3] xen/privcmd: Mark pages as dirty Souptick Joarder
2020-07-13 8:09 ` Paul Durrant
2020-07-12 3:39 ` [PATCH v3 3/3] xen/privcmd: Convert get_user_pages*() to pin_user_pages*() Souptick Joarder
2020-07-13 8:10 ` Paul Durrant
2020-07-28 7:10 ` [PATCH v3 0/3] Few bug fixes and Convert " Souptick Joarder
2020-07-28 7:38 ` Jürgen Groß
2020-08-03 5:44 ` Jürgen Groß
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