From: David Howells <dhowells@redhat.com>
To: sarah.a.sharp@linux.intel.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] xhci: Use ilog2() rather than __ffs() for calculating SEGMENT_SHIFT
Date: Thu, 28 Mar 2013 18:48:28 +0000 [thread overview]
Message-ID: <20130328184827.29679.62426.stgit@warthog.procyon.org.uk> (raw)
Use ilog2() rather than __ffs() for calculating SEGMENT_SHIFT as ilog2() can
be worked out at compile time, whereas __ffs() must be calculated at runtime.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: linux-usb@vger.kernel.org
---
drivers/usb/host/xhci.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 2c510e4..558ba50 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1235,7 +1235,7 @@ union xhci_trb {
/* Allow two commands + a link TRB, along with any reserved command TRBs */
#define MAX_RSVD_CMD_TRBS (TRBS_PER_SEGMENT - 3)
#define SEGMENT_SIZE (TRBS_PER_SEGMENT*16)
-#define SEGMENT_SHIFT (__ffs(SEGMENT_SIZE))
+#define SEGMENT_SHIFT (ilog2(SEGMENT_SIZE))
/* TRB buffer pointers can't cross 64KB boundaries */
#define TRB_MAX_BUFF_SHIFT 16
#define TRB_MAX_BUFF_SIZE (1 << TRB_MAX_BUFF_SHIFT)
next reply other threads:[~2013-03-28 18:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-28 18:48 David Howells [this message]
2013-03-28 18:48 ` [PATCH 2/2] xhci: Rename SEGMENT_SIZE and SEGMENT_SHIFT as the former is used in a.out.h David Howells
2013-03-28 20:15 ` Sarah Sharp
2013-03-28 22:32 ` David Howells
2013-03-29 0:10 ` Sarah Sharp
2013-04-02 18:07 ` David Howells
2013-04-02 19:37 ` Sarah Sharp
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