Commit-ID: c7e548b45ce85f765f6262149dd60d9956a31d60 Gitweb: http://git.kernel.org/tip/c7e548b45ce85f765f6262149dd60d9956a31d60 Author: Oleg Nesterov <[email protected]> AuthorDate: Thu, 17 Oct 2013 20:24:17 +0200 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 6 Nov 2013 12:34:28 +0100
perf: Factor out strncpy() in perf_event_mmap_event() While this is really minor, but strncpy() does the unnecessary zero-padding till the end of tmp[16] and it is called every time we are going to use the string literal. Turn these strncpy()'s into the single strlcpy() under the new label, saves 72 bytes. Signed-off-by: Oleg Nesterov <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- kernel/events/core.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 17b3c6c..4dc078d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5144,8 +5144,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) buf = kmalloc(PATH_MAX, GFP_KERNEL); if (!buf) { - name = strncpy(tmp, "//enomem", sizeof(tmp)); - goto got_name; + name = "//enomem"; + goto cpy_name; } /* * d_path() works from the end of the rb backwards, so we @@ -5154,8 +5154,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) */ name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64)); if (IS_ERR(name)) { - name = strncpy(tmp, "//toolong", sizeof(tmp)); - goto got_name; + name = "//toolong"; + goto cpy_name; } inode = file_inode(vma->vm_file); dev = inode->i_sb->s_dev; @@ -5163,30 +5163,30 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) gen = inode->i_generation; maj = MAJOR(dev); min = MINOR(dev); - + goto got_name; } else { name = (char *)arch_vma_name(vma); - if (name) { - name = strncpy(tmp, name, sizeof(tmp) - 1); - tmp[sizeof(tmp) - 1] = '\0'; - goto got_name; - } + if (name) + goto cpy_name; if (vma->vm_start <= vma->vm_mm->start_brk && vma->vm_end >= vma->vm_mm->brk) { - name = strncpy(tmp, "[heap]", sizeof(tmp)); - goto got_name; + name = "[heap]"; + goto cpy_name; } if (vma->vm_start <= vma->vm_mm->start_stack && vma->vm_end >= vma->vm_mm->start_stack) { - name = strncpy(tmp, "[stack]", sizeof(tmp)); - goto got_name; + name = "[stack]"; + goto cpy_name; } - name = strncpy(tmp, "//anon", sizeof(tmp)); - goto got_name; + name = "//anon"; + goto cpy_name; } +cpy_name: + strlcpy(tmp, name, sizeof(tmp)); + name = tmp; got_name: /* * Since our buffer works in 8 byte units we need to align our string -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
