vfs: micro-optimize acl_permission_check()

It's a hot function, and we're better off not mixing types in the mask
calculations.  The compiler just ends up mixing 16-bit and 32-bit
operations, for no good reason.

So do everything in 'unsigned int' rather than mixing 'unsigned int'
masking with a 'umode_t' (16-bit) mode variable.

This, together with the parent commit (47a150edc2: "Cache user_ns in
struct cred") makes acl_permission_check() much nicer.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2011-05-13 11:51:01 -07:00
parent 47a150edc2
commit 26cf46be95

View File

@ -179,7 +179,7 @@ EXPORT_SYMBOL(putname);
static int acl_permission_check(struct inode *inode, int mask, unsigned int flags,
int (*check_acl)(struct inode *inode, int mask, unsigned int flags))
{
umode_t mode = inode->i_mode;
unsigned int mode = inode->i_mode;
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;