shmem_parse_one(): switch to use of fs_parse()

This thing will eventually become our ->parse_param(), while
shmem_parse_options() - ->parse_monolithic().  At that point
shmem_parse_options() will start calling vfs_parse_fs_string(),
rather than calling shmem_parse_one() directly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/mm/shmem.c b/mm/shmem.c
index b392a82..6a41595 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -37,6 +37,7 @@
 #include <linux/khugepaged.h>
 #include <linux/hugetlb.h>
 #include <linux/frontswap.h>
+#include <linux/fs_parser.h>
 
 #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
 
@@ -3363,15 +3364,63 @@ static const struct export_operations shmem_export_ops = {
        .fh_to_dentry   = shmem_fh_to_dentry,
 };
 
-static int shmem_parse_one(struct shmem_options *ctx, char *opt, char *value)
+enum shmem_param {
+       Opt_gid,
+       Opt_huge,
+       Opt_mode,
+       Opt_mpol,
+       Opt_nr_blocks,
+       Opt_nr_inodes,
+       Opt_size,
+       Opt_uid,
+};
+
+static const struct fs_parameter_spec shmem_param_specs[] = {
+       fsparam_u32   ("gid",           Opt_gid),
+       fsparam_enum  ("huge",          Opt_huge),
+       fsparam_u32oct("mode",          Opt_mode),
+       fsparam_string("mpol",          Opt_mpol),
+       fsparam_string("nr_blocks",     Opt_nr_blocks),
+       fsparam_string("nr_inodes",     Opt_nr_inodes),
+       fsparam_string("size",          Opt_size),
+       fsparam_u32   ("uid",           Opt_uid),
+       {}
+};
+
+static const struct fs_parameter_enum shmem_param_enums[] = {
+       { Opt_huge,     "never",        SHMEM_HUGE_NEVER },
+       { Opt_huge,     "always",       SHMEM_HUGE_ALWAYS },
+       { Opt_huge,     "within_size",  SHMEM_HUGE_WITHIN_SIZE },
+       { Opt_huge,     "advise",       SHMEM_HUGE_ADVISE },
+       {}
+};
+
+const struct fs_parameter_description shmem_fs_parameters = {
+       .name           = "tmpfs",
+       .specs          = shmem_param_specs,
+       .enums          = shmem_param_enums,
+};
+
+static int shmem_parse_one(struct shmem_options *ctx,
+                          struct fs_parameter *param)
 {
+       struct fs_context *fc = NULL;
+       struct fs_parse_result result;
+       unsigned long long size;
        char *rest;
-       uid_t uid;
-       gid_t gid;
+       int opt;
+
+       opt = fs_parse(fc, &shmem_fs_parameters, param, &result);
+       if (opt < 0) {
+               if (opt == -ENOPARAM)
+                       return invalf(fc, "tmpfs: Unknown parameter '%s'",
+                                     param->key);
+               return opt;
+       }
 
-       if (!strcmp(opt, "size")) {
-               unsigned long long size;
-               size = memparse(value,&rest);
+       switch (opt) {
+       case Opt_size:
+               size = memparse(param->string, &rest);
                if (*rest == '%') {
                        size <<= PAGE_SHIFT;
                        size *= totalram_pages();
@@ -3379,74 +3428,65 @@ static int shmem_parse_one(struct shmem_options *ctx, char *opt, char *value)
                        rest++;
                }
                if (*rest)
-                       goto bad_val;
+                       goto bad_value;
                ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE);
                ctx->seen |= SHMEM_SEEN_BLOCKS;
-       } else if (!strcmp(opt, "nr_blocks")) {
-               ctx->blocks = memparse(value, &rest);
+               break;
+       case Opt_nr_blocks:
+               ctx->blocks = memparse(param->string, &rest);
                if (*rest)
-                       goto bad_val;
+                       goto bad_value;
                ctx->seen |= SHMEM_SEEN_BLOCKS;
-       } else if (!strcmp(opt, "nr_inodes")) {
-               ctx->inodes = memparse(value, &rest);
+               break;
+       case Opt_nr_inodes:
+               ctx->inodes = memparse(param->string, &rest);
                if (*rest)
-                       goto bad_val;
+                       goto bad_value;
                ctx->seen |= SHMEM_SEEN_INODES;
-       } else if (!strcmp(opt, "mode")) {
-               ctx->mode = simple_strtoul(value, &rest, 8) & 07777;
-               if (*rest)
-                       goto bad_val;
-       } else if (!strcmp(opt, "uid")) {
-               uid = simple_strtoul(value, &rest, 0);
-               if (*rest)
-                       goto bad_val;
-               ctx->uid = make_kuid(current_user_ns(), uid);
+               break;
+       case Opt_mode:
+               ctx->mode = result.uint_32 & 07777;
+               break;
+       case Opt_uid:
+               ctx->uid = make_kuid(current_user_ns(), result.uint_32);
                if (!uid_valid(ctx->uid))
-                       goto bad_val;
-       } else if (!strcmp(opt, "gid")) {
-               gid = simple_strtoul(value, &rest, 0);
-               if (*rest)
-                       goto bad_val;
-               ctx->gid = make_kgid(current_user_ns(), gid);
+                       goto bad_value;
+               break;
+       case Opt_gid:
+               ctx->gid = make_kgid(current_user_ns(), result.uint_32);
                if (!gid_valid(ctx->gid))
-                       goto bad_val;
-#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
-       } else if (!strcmp(opt, "huge")) {
-               int huge;
-               huge = shmem_parse_huge(value);
-               if (huge < 0)
-                       goto bad_val;
-               if (!has_transparent_hugepage() &&
-                               huge != SHMEM_HUGE_NEVER)
-                       goto bad_val;
-               ctx->huge = huge;
+                       goto bad_value;
+               break;
+       case Opt_huge:
+               ctx->huge = result.uint_32;
+               if (ctx->huge != SHMEM_HUGE_NEVER &&
+                   !(IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
+                     has_transparent_hugepage()))
+                       goto unsupported_parameter;
                ctx->seen |= SHMEM_SEEN_HUGE;
-#endif
-#ifdef CONFIG_NUMA
-       } else if (!strcmp(opt, "mpol")) {
-               mpol_put(ctx->mpol);
-               ctx->mpol = NULL;
-               if (mpol_parse_str(value, &ctx->mpol))
-                       goto bad_val;
-#endif
-       } else {
-               pr_err("tmpfs: Bad mount option %s\n", opt);
-               return -EINVAL;
+               break;
+       case Opt_mpol:
+               if (IS_ENABLED(CONFIG_NUMA)) {
+                       mpol_put(ctx->mpol);
+                       ctx->mpol = NULL;
+                       if (mpol_parse_str(param->string, &ctx->mpol))
+                               goto bad_value;
+                       break;
+               }
+               goto unsupported_parameter;
        }
        return 0;
 
-bad_val:
-       pr_err("tmpfs: Bad value '%s' for mount option '%s'\n",
-              value, opt);
-       return -EINVAL;
+unsupported_parameter:
+       return invalf(fc, "tmpfs: Unsupported parameter '%s'", param->key);
+bad_value:
+       return invalf(fc, "tmpfs: Bad value for '%s'", param->key);
 }
 
 static int shmem_parse_options(char *options, struct shmem_options *ctx)
 {
-       char *this_char, *value;
-
        while (options != NULL) {
-               this_char = options;
+               char *this_char = options;
                for (;;) {
                        /*
                         * NUL-terminate this option: unfortunately,
@@ -3462,17 +3502,26 @@ static int shmem_parse_options(char *options, struct shmem_options *ctx)
                                break;
                        }
                }
-               if (!*this_char)
-                       continue;
-               if ((value = strchr(this_char,'=')) != NULL) {
-                       *value++ = 0;
-               } else {
-                       pr_err("tmpfs: No value for mount option '%s'\n",
-                              this_char);
-                       goto error;
+               if (*this_char) {
+                       char *value = strchr(this_char,'=');
+                       struct fs_parameter param = {
+                               .key    = this_char,
+                               .type   = fs_value_is_string,
+                       };
+                       int err;
+
+                       if (value) {
+                               *value++ = '\0';
+                               param.size = strlen(value);
+                               param.string = kstrdup(value, GFP_KERNEL);
+                               if (!param.string)
+                                       goto error;
+                       }
+                       err = shmem_parse_one(ctx, &param);
+                       kfree(param.string);
+                       if (err)
+                               goto error;
                }
-               if (shmem_parse_one(ctx, this_char, value) < 0)
-                       goto error;
        }
        return 0;