diff options
| author | Rasmus Villemoes | 2015-11-24 13:33:47 +0100 |
|---|---|---|
| committer | Jiri Kosina | 2015-11-27 00:02:59 +0100 |
| commit | 92529623d242cea4440958d7bcebdf291f4ab15e (patch) | |
| tree | 642b9391e9d698fd623a640582264c7f33ba3042 /drivers/hid | |
| parent | cc8a9d79222c6b259ea9eceef21b94a5610616f0 (diff) | |
HID: debug: improve hid_debug_event()
The code in hid_debug_event() causes horrible code generation. First,
we do a strlen() call for every byte we copy (we're doing a store to
global memory, so gcc has no way of proving that strlen(buf) doesn't
change). Second, since both i, list->tail and HID_DEBUG_BUFSIZE have
signed type, the modulo computation has to take into account the
possibility that list->tail+i is negative, so it's not just a simple
and.
Fix the former by simply not doing strlen() at all (we have to load
buf[i] anyway, so testing it is almost free) and the latter by
changing i to unsigned. This cuts 29% (69 bytes) of the size of the
function.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid')
| -rw-r--r-- | drivers/hid/hid-debug.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index 2886b645ced7..acfb522a432a 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -659,13 +659,13 @@ EXPORT_SYMBOL_GPL(hid_dump_device); /* enqueue string to 'events' ring buffer */ void hid_debug_event(struct hid_device *hdev, char *buf) { - int i; + unsigned i; struct hid_debug_list *list; unsigned long flags; spin_lock_irqsave(&hdev->debug_list_lock, flags); list_for_each_entry(list, &hdev->debug_list, node) { - for (i = 0; i < strlen(buf); i++) + for (i = 0; buf[i]; i++) list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = buf[i]; list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; |