From 3272c544da48f8915a0e34189182aed029bd0f2b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 12 Sep 2013 12:40:15 -0700 Subject: [PATCH] vfs: use __getname/__putname for getcwd() system call It's a pathname. It should use the pathname allocators and deallocators, and PATH_MAX instead of PAGE_SIZE. Never mind that the two are commonly the same. With this, the allocations scale up nicely too, and I can do getcwd() system calls at a rate of about 300M/s, with no lock contention anywhere. Of course, nobody sane does that, especially since getcwd() is traditionally a very slow operation in Unix. But this was also the simplest way to benchmark the prepend_path() improvements by Waiman, and once I saw the profiles I couldn't leave it well enough alone. But apart from being an performance improvement (from using per-cpu slab allocators instead of the raw page allocator), it's actually a valid and real cleanup. Signed-off-by: Linus "OCD" Torvalds --- fs/dcache.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 29d58212aaf0..91e551b5af59 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -3049,7 +3049,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) { int error; struct path pwd, root; - char *page = (char *) __get_free_page(GFP_USER); + char *page = __getname(); if (!page) return -ENOMEM; @@ -3061,8 +3061,8 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) br_read_lock(&vfsmount_lock); if (!d_unlinked(pwd.dentry)) { unsigned long len; - char *cwd = page + PAGE_SIZE; - int buflen = PAGE_SIZE; + char *cwd = page + PATH_MAX; + int buflen = PATH_MAX; prepend(&cwd, &buflen, "\0", 1); error = prepend_path(&pwd, &root, &cwd, &buflen); @@ -3080,7 +3080,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) } error = -ERANGE; - len = PAGE_SIZE + page - cwd; + len = PATH_MAX + page - cwd; if (len <= size) { error = len; if (copy_to_user(buf, cwd, len)) @@ -3092,7 +3092,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) } out: - free_page((unsigned long) page); + __putname(page); return error; } -- 2.30.2