[PATCH 2/2] usb: gadget: FunctionFS: Refactor option parsing

From: Michal Nazarewicz
Date: Wed Jan 09 2013 - 04:18:08 EST


From: Michal Nazarewicz <mina86@xxxxxxxxxx>

The use of memcmp() is clever and all and maybe even it makes parsing a
bit faster (since only options with given length need to be checked) but
option parsing is hardly a critical path and the additional code
complexity is not worth it.

Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
drivers/usb/gadget/f_fs.c | 55 ++++++++++++++------------------------------
1 files changed, 18 insertions(+), 37 deletions(-)

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 38388d7..6a7e187 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -1126,45 +1126,26 @@ static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
}

/* Interpret option */
- switch (eq - opts) {
- case 5:
- if (!memcmp(opts, "rmode", 5))
- data->root_mode = (value & 0555) | S_IFDIR;
- else if (!memcmp(opts, "fmode", 5))
- data->perms.mode = (value & 0666) | S_IFREG;
- else
- goto invalid;
- break;
-
- case 4:
- if (!memcmp(opts, "mode", 4)) {
- data->root_mode = (value & 0555) | S_IFDIR;
- data->perms.mode = (value & 0666) | S_IFREG;
- } else {
- goto invalid;
+ if (!strcmp(opts, "rmode")) {
+ data->root_mode = (value & 0555) | S_IFDIR;
+ } else if (!strcmp(opts, "fmode")) {
+ data->perms.mode = (value & 0666) | S_IFREG;
+ } else if (!strcmp(opts, "mode")) {
+ data->root_mode = (value & 0555) | S_IFDIR;
+ data->perms.mode = (value & 0666) | S_IFREG;
+ } else if (!strcmp(opts, "uid")) {
+ data->perms.uid = make_kuid(current_user_ns(), value);
+ if (!uid_valid(data->perms.uid)) {
+ pr_err("%s: unmapped value: %lu\n", opts, value);
+ return -EINVAL;
}
- break;
-
- case 3:
- if (!memcmp(opts, "uid", 3)) {
- data->perms.uid = make_kuid(current_user_ns(), value);
- if (!uid_valid(data->perms.uid)) {
- pr_err("%s: unmapped value: %lu\n", opts, value);
- return -EINVAL;
- }
- } else if (!memcmp(opts, "gid", 3)) {
- data->perms.gid = make_kgid(current_user_ns(), value);
- if (!gid_valid(data->perms.gid)) {
- pr_err("%s: unmapped value: %lu\n", opts, value);
- return -EINVAL;
- }
- } else {
- goto invalid;
+ } else if (!strcmp(opts, "gid")) {
+ data->perms.gid = make_kgid(current_user_ns(), value);
+ if (!gid_valid(data->perms.gid)) {
+ pr_err("%s: unmapped value: %lu\n", opts, value);
+ return -EINVAL;
}
- break;
-
- default:
-invalid:
+ } else {
pr_err("%s: invalid option\n", opts);
return -EINVAL;
}
--
1.7.7.3

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