Messages in this thread | | | Subject | Re: [PATCH] xhci: Use ffs() to find page size in xhci_mem_init() | From | Mathias Nyman <> | Date | Thu, 7 Feb 2019 11:04:28 +0200 |
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On 07.02.2019 02:03, Andrey Smirnov wrote: > Get page size order using ffs() instead of open coding it with a loop. > > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> > Cc: Mathias Nyman <mathias.nyman@intel.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: linux-usb@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > --- > drivers/usb/host/xhci-mem.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c > index 36a3eb8849f1..44b43c3d819f 100644 > --- a/drivers/usb/host/xhci-mem.c > +++ b/drivers/usb/host/xhci-mem.c > @@ -2362,11 +2362,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) > page_size = readl(&xhci->op_regs->page_size); > xhci_dbg_trace(xhci, trace_xhci_dbg_init, > "Supported page size register = 0x%x", page_size); > - for (i = 0; i < 16; i++) { > - if ((0x1 & page_size) != 0) > - break; > - page_size = page_size >> 1; > - } > + i = ffs(page_size); > if (i < 16) > xhci_dbg_trace(xhci, trace_xhci_dbg_init, > "Supported page size of %iK", (1 << (i+12)) / 1024);
Hi
using ffs() is a welcome change, but it will give different a result than the loop.
*old loop valid page_size value if i < 16 *ffs() valid page_size value if i >= 1 and i < 17
-Mathias
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