[PATCH] block: cmdline-parser: add support for hidden disk space

[PATCH] block: cmdline-parser: add support for hidden disk space

[Shawn Lin]

cmdline-partition now only support continuous disk space taken from
cmdline. When we need to reserve a disk space, for instance, 100m between
mmcblk0p1 and mmcblk0p2 for special use and wouldn't let kernel space
realize this "disk hole", we add this patch to ship adding this kind of
"disk hole" into the partition table. For any such cases, simply append
"hidden" to the end of subpart which is need to be reserved.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

 block/cmdline-parser.c         | 12 +++++++++++-
 include/linux/cmdline-parser.h |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/block/cmdline-parser.c b/block/cmdline-parser.c
index 9dbc67e..feecbcc 100644
--- a/block/cmdline-parser.c
+++ b/block/cmdline-parser.c
@@ -68,6 +68,11 @@ static int parse_subpart(struct cmdline_subpart **subpart, char *partdef)
 		partdef += 2;
 	}
 
+	if (!strncmp(partdef, "hidden", 6)) {
+		new_subpart->flags |= PF_HIDDEN;
+		partdef += 6;
+	}
+
 	*subpart = new_subpart;
 	return 0;
 fail:
@@ -128,7 +133,9 @@ static int parse_parts(struct cmdline_parts **parts, const char *bdevdef)
 		if (ret)
 			goto fail;
 
-		newparts->nr_subparts++;
+		if (!(subpart->flags & PF_HIDDEN))
+			newparts->nr_subparts++;
+
 		next_subpart = &(*next_subpart)->next_subpart;
 	}
 
@@ -245,6 +252,9 @@ int cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size,
 
 		from += subpart->size;
 
+		if (subpart->flags & PF_HIDDEN)
+			continue;
+
 		if (add_part(slot, subpart, param))
 			break;
 	}
diff --git a/include/linux/cmdline-parser.h b/include/linux/cmdline-parser.h
index 2e6dce6..7c1cb3c 100644
--- a/include/linux/cmdline-parser.h
+++ b/include/linux/cmdline-parser.h
@@ -14,6 +14,7 @@
 /* partition flags */
 #define PF_RDONLY                   0x01 /* Device is read only */
 #define PF_POWERUP_LOCK             0x02 /* Always locked after reset */
+#define PF_HIDDEN                   0x04 /* Hidden from partition table */
 
 struct cmdline_subpart {
 	char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */
-- 
2.3.7

Re: [PATCH] block: cmdline-parser: add support for hidden disk space

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 5984 bytes --]

Hi Shawn,

[auto build test results on v4.3-rc3 -- if it's inappropriate base, please ignore]

config: x86_64-randconfig-x005-201539 (attached as .config)
reproduce:
  git checkout 937e3ebb4c7763e6120eda4a7e5b8c96bd710a9f
  # save the attached .config to linux build tree
  make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   In file included from include/uapi/linux/stddef.h:1:0,
                    from include/linux/stddef.h:4,
                    from include/uapi/linux/posix_types.h:4,
                    from include/uapi/linux/types.h:13,
                    from include/linux/types.h:5,
                    from include/uapi/linux/capability.h:16,
                    from include/linux/capability.h:15,
                    from include/linux/sched.h:15,
                    from include/linux/blkdev.h:4,
                    from include/linux/cmdline-parser.h:10,
                    from block/cmdline-parser.c:8:
   block/cmdline-parser.c: In function 'parse_parts':
   block/cmdline-parser.c:136:9: error: 'subpart' undeclared (first use in this function)
      if (!(subpart->flags & PF_HIDDEN))
            ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> block/cmdline-parser.c:136:3: note: in expansion of macro 'if'
      if (!(subpart->flags & PF_HIDDEN))
      ^
   block/cmdline-parser.c:136:9: note: each undeclared identifier is reported only once for each function it appears in
      if (!(subpart->flags & PF_HIDDEN))
            ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> block/cmdline-parser.c:136:3: note: in expansion of macro 'if'
      if (!(subpart->flags & PF_HIDDEN))
      ^

vim +/if +136 block/cmdline-parser.c

     2	 * Parse command line, get partition information
     3	 *
     4	 * Written by Cai Zhiyong <caizhiyong@huawei.com>
     5	 *
     6	 */
     7	#include <linux/export.h>
   > 8	#include <linux/cmdline-parser.h>
     9	
    10	static int parse_subpart(struct cmdline_subpart **subpart, char *partdef)
    11	{
    12		int ret = 0;
    13		struct cmdline_subpart *new_subpart;
    14	
    15		*subpart = NULL;
    16	
    17		new_subpart = kzalloc(sizeof(struct cmdline_subpart), GFP_KERNEL);
    18		if (!new_subpart)
    19			return -ENOMEM;
    20	
    21		if (*partdef == '-') {
    22			new_subpart->size = (sector_t)(~0ULL);
    23			partdef++;
    24		} else {
    25			new_subpart->size = (sector_t)memparse(partdef, &partdef);
    26			if (new_subpart->size < (sector_t)PAGE_SIZE) {
    27				pr_warn("cmdline partition size is invalid.");
    28				ret = -EINVAL;
    29				goto fail;
    30			}
    31		}
    32	
    33		if (*partdef == '@') {
    34			partdef++;
    35			new_subpart->from = (sector_t)memparse(partdef, &partdef);
    36		} else {
    37			new_subpart->from = (sector_t)(~0ULL);
    38		}
    39	
    40		if (*partdef == '(') {
    41			int length;
    42			char *next = strchr(++partdef, ')');
    43	
    44			if (!next) {
    45				pr_warn("cmdline partition format is invalid.");
    46				ret = -EINVAL;
    47				goto fail;
    48			}
    49	
    50			length = min_t(int, next - partdef,
    51				       sizeof(new_subpart->name) - 1);
    52			strncpy(new_subpart->name, partdef, length);
    53			new_subpart->name[length] = '\0';
    54	
    55			partdef = ++next;
    56		} else
    57			new_subpart->name[0] = '\0';
    58	
    59		new_subpart->flags = 0;
    60	
    61		if (!strncmp(partdef, "ro", 2)) {
    62			new_subpart->flags |= PF_RDONLY;
    63			partdef += 2;
    64		}
    65	
    66		if (!strncmp(partdef, "lk", 2)) {
    67			new_subpart->flags |= PF_POWERUP_LOCK;
    68			partdef += 2;
    69		}
    70	
    71		if (!strncmp(partdef, "hidden", 6)) {
    72			new_subpart->flags |= PF_HIDDEN;
    73			partdef += 6;
    74		}
    75	
    76		*subpart = new_subpart;
    77		return 0;
    78	fail:
    79		kfree(new_subpart);
    80		return ret;
    81	}
    82	
    83	static void free_subpart(struct cmdline_parts *parts)
    84	{
    85		struct cmdline_subpart *subpart;
    86	
    87		while (parts->subpart) {
    88			subpart = parts->subpart;
    89			parts->subpart = subpart->next_subpart;
    90			kfree(subpart);
    91		}
    92	}
    93	
    94	static int parse_parts(struct cmdline_parts **parts, const char *bdevdef)
    95	{
    96		int ret = -EINVAL;
    97		char *next;
    98		int length;
    99		struct cmdline_subpart **next_subpart;
   100		struct cmdline_parts *newparts;
   101		char buf[BDEVNAME_SIZE + 32 + 4];
   102	
   103		*parts = NULL;
   104	
   105		newparts = kzalloc(sizeof(struct cmdline_parts), GFP_KERNEL);
   106		if (!newparts)
   107			return -ENOMEM;
   108	
   109		next = strchr(bdevdef, ':');
   110		if (!next) {
   111			pr_warn("cmdline partition has no block device.");
   112			goto fail;
   113		}
   114	
   115		length = min_t(int, next - bdevdef, sizeof(newparts->name) - 1);
   116		strncpy(newparts->name, bdevdef, length);
   117		newparts->name[length] = '\0';
   118		newparts->nr_subparts = 0;
   119	
   120		next_subpart = &newparts->subpart;
   121	
   122		while (next && *(++next)) {
   123			bdevdef = next;
   124			next = strchr(bdevdef, ',');
   125	
   126			length = (!next) ? (sizeof(buf) - 1) :
   127				min_t(int, next - bdevdef, sizeof(buf) - 1);
   128	
   129			strncpy(buf, bdevdef, length);
   130			buf[length] = '\0';
   131	
   132			ret = parse_subpart(next_subpart, buf);
   133			if (ret)
   134				goto fail;
   135	
 > 136			if (!(subpart->flags & PF_HIDDEN))
   137				newparts->nr_subparts++;
   138	
   139			next_subpart = &(*next_subpart)->next_subpart;

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

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Re: [PATCH] block: cmdline-parser: add support for hidden disk space

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1136 bytes --]

Hi Shawn,

[auto build test results on v4.3-rc3 -- if it's inappropriate base, please ignore]

config: i386-randconfig-x005-201539 (attached as .config)
reproduce:
  git checkout 937e3ebb4c7763e6120eda4a7e5b8c96bd710a9f
  # save the attached .config to linux build tree
  make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   block/cmdline-parser.c: In function 'parse_parts':
>> block/cmdline-parser.c:136:9: error: 'subpart' undeclared (first use in this function)
      if (!(subpart->flags & PF_HIDDEN))
            ^
   block/cmdline-parser.c:136:9: note: each undeclared identifier is reported only once for each function it appears in

vim +/subpart +136 block/cmdline-parser.c

   130			buf[length] = '\0';
   131	
   132			ret = parse_subpart(next_subpart, buf);
   133			if (ret)
   134				goto fail;
   135	
 > 136			if (!(subpart->flags & PF_HIDDEN))
   137				newparts->nr_subparts++;
   138	
   139			next_subpart = &(*next_subpart)->next_subpart;

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

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