LinuxLists.cc - [PATCH v3 8/9] xen/gntdev.c: Convert to use vm_map

2019-02-13 15:10:18

Subject: [PATCH v3 8/9] xen/gntdev.c: Convert to use vm_map_pages()

Convert to use vm_map_pages() to map range of kernel
memory to user vma.

map->count is passed to vm_map_pages() and internal API
verify map->count against count ( count = vma_pages(vma))
for page array boundary overrun. With this count is not
needed inside gntdev_mmap() and it could be replaced with
vma_pages(vma).

Signed-off-by: Souptick Joarder <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
---
drivers/xen/gntdev.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 5efc5ee..7f65ba3 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -1082,18 +1082,17 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
{
struct gntdev_priv *priv = flip->private_data;
int index = vma->vm_pgoff;
- int count = vma_pages(vma);
struct gntdev_grant_map *map;
- int i, err = -EINVAL;
+ int err = -EINVAL;

if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
return -EINVAL;

pr_debug("map %d+%d at %lx (pgoff %lx)\n",
- index, count, vma->vm_start, vma->vm_pgoff);
+ index, vma_pages(vma), vma->vm_start, vma->vm_pgoff);

mutex_lock(&priv->lock);
- map = gntdev_find_map_index(priv, index, count);
+ map = gntdev_find_map_index(priv, index, vma_pages(vma));
if (!map)
goto unlock_out;
if (use_ptemod && map->vma)
@@ -1145,12 +1144,9 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
goto out_put_map;

if (!use_ptemod) {
- for (i = 0; i < count; i++) {
- err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
- map->pages[i]);
- if (err)
- goto out_put_map;
- }
+ err = vm_map_pages(vma, map->pages, map->count);
+ if (err)
+ goto out_put_map;
} else {
#ifdef CONFIG_X86
/*
--
1.9.1

2019-02-15 00:50:01

by kernel test robot

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Subject: Re: [PATCH v3 8/9] xen/gntdev.c: Convert to use vm_map_pages()

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2019-02-15 00:57:35

by kernel test robot

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Subject: Re: [PATCH v3 8/9] xen/gntdev.c: Convert to use vm_map_pages()

Hi Souptick,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.0-rc4 next-20190214]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Souptick-Joarder/mm-Use-vm_map_pages-and-vm_map_pages_zero-API/20190214-213457
config: x86_64-fedora-25 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

All warnings (new ones prefixed by >>):

drivers/xen/gntdev.c: In function 'gntdev_mmap':
drivers/xen/gntdev.c:23:21: warning: format '%d' expects argument of type 'int', but argument 4 has type 'long unsigned int' [-Wformat=]
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
^
>> include/linux/dynamic_debug.h:127:35: note: in expansion of macro 'pr_fmt'
__dynamic_pr_debug(&descriptor, pr_fmt(fmt), \
^~~~~~
include/linux/printk.h:335:2: note: in expansion of macro 'dynamic_pr_debug'
dynamic_pr_debug(fmt, ##__VA_ARGS__)
^~~~~~~~~~~~~~~~
>> drivers/xen/gntdev.c:1091:2: note: in expansion of macro 'pr_debug'
pr_debug("map %d+%d at %lx (pgoff %lx)\n",
^~~~~~~~
--
drivers//xen/gntdev.c: In function 'gntdev_mmap':
drivers//xen/gntdev.c:23:21: warning: format '%d' expects argument of type 'int', but argument 4 has type 'long unsigned int' [-Wformat=]
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
^
>> include/linux/dynamic_debug.h:127:35: note: in expansion of macro 'pr_fmt'
__dynamic_pr_debug(&descriptor, pr_fmt(fmt), \
^~~~~~
include/linux/printk.h:335:2: note: in expansion of macro 'dynamic_pr_debug'
dynamic_pr_debug(fmt, ##__VA_ARGS__)
^~~~~~~~~~~~~~~~
drivers//xen/gntdev.c:1091:2: note: in expansion of macro 'pr_debug'
pr_debug("map %d+%d at %lx (pgoff %lx)\n",
^~~~~~~~

vim +/pr_debug +1091 drivers/xen/gntdev.c

ab31523c2 Gerd Hoffmann 2010-12-14 1080
ab31523c2 Gerd Hoffmann 2010-12-14 1081 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
ab31523c2 Gerd Hoffmann 2010-12-14 1082 {
ab31523c2 Gerd Hoffmann 2010-12-14 1083 struct gntdev_priv *priv = flip->private_data;
ab31523c2 Gerd Hoffmann 2010-12-14 1084 int index = vma->vm_pgoff;
1d3145675 Oleksandr Andrushchenko 2018-07-20 1085 struct gntdev_grant_map *map;
29222b665 Souptick Joarder 2019-02-13 1086 int err = -EINVAL;
ab31523c2 Gerd Hoffmann 2010-12-14 1087
ab31523c2 Gerd Hoffmann 2010-12-14 1088 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
ab31523c2 Gerd Hoffmann 2010-12-14 1089 return -EINVAL;
ab31523c2 Gerd Hoffmann 2010-12-14 1090
ab31523c2 Gerd Hoffmann 2010-12-14 @1091 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
29222b665 Souptick Joarder 2019-02-13 1092 index, vma_pages(vma), vma->vm_start, vma->vm_pgoff);
ab31523c2 Gerd Hoffmann 2010-12-14 1093
1401c00e5 David Vrabel 2015-01-09 1094 mutex_lock(&priv->lock);
29222b665 Souptick Joarder 2019-02-13 1095 map = gntdev_find_map_index(priv, index, vma_pages(vma));
ab31523c2 Gerd Hoffmann 2010-12-14 1096 if (!map)
ab31523c2 Gerd Hoffmann 2010-12-14 1097 goto unlock_out;
aab8f11a6 Daniel De Graaf 2011-02-03 1098 if (use_ptemod && map->vma)
ab31523c2 Gerd Hoffmann 2010-12-14 1099 goto unlock_out;
aab8f11a6 Daniel De Graaf 2011-02-03 1100 if (use_ptemod && priv->mm != vma->vm_mm) {
283c0972d Joe Perches 2013-06-28 1101 pr_warn("Huh? Other mm?\n");
ab31523c2 Gerd Hoffmann 2010-12-14 1102 goto unlock_out;
ab31523c2 Gerd Hoffmann 2010-12-14 1103 }
ab31523c2 Gerd Hoffmann 2010-12-14 1104
c5f7c5a9a Elena Reshetova 2017-03-06 1105 refcount_inc(&map->users);
68b025c81 Daniel De Graaf 2011-02-03 1106
ab31523c2 Gerd Hoffmann 2010-12-14 1107 vma->vm_ops = &gntdev_vmops;
ab31523c2 Gerd Hoffmann 2010-12-14 1108
30faaafdf Boris Ostrovsky 2016-11-21 1109 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
d79647aea Daniel De Graaf 2011-03-07 1110
d79647aea Daniel De Graaf 2011-03-07 1111 if (use_ptemod)
e8e937be9 Stefano Stabellini 2012-04-03 1112 vma->vm_flags |= VM_DONTCOPY;
ab31523c2 Gerd Hoffmann 2010-12-14 1113
ab31523c2 Gerd Hoffmann 2010-12-14 1114 vma->vm_private_data = map;
aab8f11a6 Daniel De Graaf 2011-02-03 1115
aab8f11a6 Daniel De Graaf 2011-02-03 1116 if (use_ptemod)
ab31523c2 Gerd Hoffmann 2010-12-14 1117 map->vma = vma;
ab31523c2 Gerd Hoffmann 2010-12-14 1118
12996fc38 Daniel De Graaf 2011-02-09 1119 if (map->flags) {
12996fc38 Daniel De Graaf 2011-02-09 1120 if ((vma->vm_flags & VM_WRITE) &&
12996fc38 Daniel De Graaf 2011-02-09 1121 (map->flags & GNTMAP_readonly))
a93e20a83 Dan Carpenter 2011-03-19 1122 goto out_unlock_put;
12996fc38 Daniel De Graaf 2011-02-09 1123 } else {
aab8f11a6 Daniel De Graaf 2011-02-03 1124 map->flags = GNTMAP_host_map;
ab31523c2 Gerd Hoffmann 2010-12-14 1125 if (!(vma->vm_flags & VM_WRITE))
ab31523c2 Gerd Hoffmann 2010-12-14 1126 map->flags |= GNTMAP_readonly;
12996fc38 Daniel De Graaf 2011-02-09 1127 }
ab31523c2 Gerd Hoffmann 2010-12-14 1128
1401c00e5 David Vrabel 2015-01-09 1129 mutex_unlock(&priv->lock);
f0a70c882 Daniel De Graaf 2011-01-07 1130
aab8f11a6 Daniel De Graaf 2011-02-03 1131 if (use_ptemod) {
298d275d4 Juergen Gross 2017-10-25 1132 map->pages_vm_start = vma->vm_start;
ab31523c2 Gerd Hoffmann 2010-12-14 1133 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
ab31523c2 Gerd Hoffmann 2010-12-14 1134 vma->vm_end - vma->vm_start,
ab31523c2 Gerd Hoffmann 2010-12-14 1135 find_grant_ptes, map);
ab31523c2 Gerd Hoffmann 2010-12-14 1136 if (err) {
283c0972d Joe Perches 2013-06-28 1137 pr_warn("find_grant_ptes() failure.\n");
90b6f3054 Daniel De Graaf 2011-02-03 1138 goto out_put_map;
ab31523c2 Gerd Hoffmann 2010-12-14 1139 }
aab8f11a6 Daniel De Graaf 2011-02-03 1140 }
ab31523c2 Gerd Hoffmann 2010-12-14 1141
1d3145675 Oleksandr Andrushchenko 2018-07-20 1142 err = gntdev_map_grant_pages(map);
90b6f3054 Daniel De Graaf 2011-02-03 1143 if (err)
90b6f3054 Daniel De Graaf 2011-02-03 1144 goto out_put_map;
f0a70c882 Daniel De Graaf 2011-01-07 1145
aab8f11a6 Daniel De Graaf 2011-02-03 1146 if (!use_ptemod) {
29222b665 Souptick Joarder 2019-02-13 1147 err = vm_map_pages(vma, map->pages, map->count);
aab8f11a6 Daniel De Graaf 2011-02-03 1148 if (err)
90b6f3054 Daniel De Graaf 2011-02-03 1149 goto out_put_map;
923b2919e David Vrabel 2014-12-18 1150 } else {
923b2919e David Vrabel 2014-12-18 1151 #ifdef CONFIG_X86
923b2919e David Vrabel 2014-12-18 1152 /*
923b2919e David Vrabel 2014-12-18 1153 * If the PTEs were not made special by the grant map
923b2919e David Vrabel 2014-12-18 1154 * hypercall, do so here.
923b2919e David Vrabel 2014-12-18 1155 *
923b2919e David Vrabel 2014-12-18 1156 * This is racy since the mapping is already visible
923b2919e David Vrabel 2014-12-18 1157 * to userspace but userspace should be well-behaved
923b2919e David Vrabel 2014-12-18 1158 * enough to not touch it until the mmap() call
923b2919e David Vrabel 2014-12-18 1159 * returns.
923b2919e David Vrabel 2014-12-18 1160 */
923b2919e David Vrabel 2014-12-18 1161 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
923b2919e David Vrabel 2014-12-18 1162 apply_to_page_range(vma->vm_mm, vma->vm_start,
923b2919e David Vrabel 2014-12-18 1163 vma->vm_end - vma->vm_start,
923b2919e David Vrabel 2014-12-18 1164 set_grant_ptes_as_special, NULL);
923b2919e David Vrabel 2014-12-18 1165 }
923b2919e David Vrabel 2014-12-18 1166 #endif
aab8f11a6 Daniel De Graaf 2011-02-03 1167 }
aab8f11a6 Daniel De Graaf 2011-02-03 1168
f0a70c882 Daniel De Graaf 2011-01-07 1169 return 0;
f0a70c882 Daniel De Graaf 2011-01-07 1170
ab31523c2 Gerd Hoffmann 2010-12-14 1171 unlock_out:
1401c00e5 David Vrabel 2015-01-09 1172 mutex_unlock(&priv->lock);
ab31523c2 Gerd Hoffmann 2010-12-14 1173 return err;
90b6f3054 Daniel De Graaf 2011-02-03 1174
a93e20a83 Dan Carpenter 2011-03-19 1175 out_unlock_put:
1401c00e5 David Vrabel 2015-01-09 1176 mutex_unlock(&priv->lock);
90b6f3054 Daniel De Graaf 2011-02-03 1177 out_put_map:
cf2acf66a Ross Lagerwall 2018-01-09 1178 if (use_ptemod) {
84e4075d6 Daniel De Graaf 2011-02-09 1179 map->vma = NULL;
cf2acf66a Ross Lagerwall 2018-01-09 1180 unmap_grant_pages(map, 0, map->count);
cf2acf66a Ross Lagerwall 2018-01-09 1181 }
16a1d0225 Daniel De Graaf 2013-01-02 1182 gntdev_put_map(priv, map);
90b6f3054 Daniel De Graaf 2011-02-03 1183 return err;
ab31523c2 Gerd Hoffmann 2010-12-14 1184 }
ab31523c2 Gerd Hoffmann 2010-12-14 1185

:::::: The code at line 1091 was first introduced by commit
:::::: ab31523c2fcac557226bac72cbdf5fafe01f9a26 xen/gntdev: allow usermode to map granted pages

:::::: TO: Gerd Hoffmann <[email protected]>
:::::: CC: Konrad Rzeszutek Wilk <[email protected]>

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation

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