On 15.02.2024 18:02, Bjorn Helgaas wrote: > On Thu, Feb 15, 2024 at 02:35:13PM +0100, Alexander Lobakin wrote: >> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> >> Date: Thu, 15 Feb 2024 11:39:31 +0100 >> >>> According to [1], msleep should be used for large sleeps, such as the >>> 100-ish ms one in this function. Comply with the guide and use it. >>> >>> [1] https://www.kernel.org/doc/Documentation/timers/timers-howto.txt >>> >>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> >>> --- >>> Tested on Qualcomm SC8280XP CRD >>> --- >>> drivers/pci/controller/dwc/pcie-designware.c | 2 +- >>> drivers/pci/controller/dwc/pcie-designware.h | 3 +-- >>> 2 files changed, 2 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c >>> index 250cf7f40b85..abce6afceb91 100644 >>> --- a/drivers/pci/controller/dwc/pcie-designware.c >>> +++ b/drivers/pci/controller/dwc/pcie-designware.c >>> @@ -655,7 +655,7 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci) >>> if (dw_pcie_link_up(pci)) >>> break; >>> >>> - usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX); >>> + msleep(LINK_WAIT_MSLEEP_MAX); >> >> Just use fsleep(LINK_WAIT_USLEEP_MAX) and let the kernel decide which >> function to pick. IMO, fsleep only makes sense when the argument is variable.. This way, we can save on bothering the compiler or adding an unnecessary branch > > Odd. > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/timers/timers-howto.rst?id=v6.7#n114 > mentions fsleep() (with no real guidance about when to use it), but > https://www.kernel.org/doc/Documentation/timers/timers-howto.txt > seems to be a stale copy from 2017, before fsleep() was added. I > emailed helpdesk@xxxxxxxxxx to see if the stale content can be > removed. > > I do think fsleep() should be more widely used. > >>> /* Parameters for the waiting for link up routine */ >>> #define LINK_WAIT_MAX_RETRIES 10 >>> -#define LINK_WAIT_USLEEP_MIN 90000 >>> -#define LINK_WAIT_USLEEP_MAX 100000 >>> +#define LINK_WAIT_MSLEEP_MAX 100 > > Since you're touching this anyway, it would be helpful to include the > units on the timeout. > > USLEEP/MSLEEP is definitely a hint, but I think the "SLEEP" part > suggests something about atomic/non-atomic context and isn't relevant > to the time interval itself, and something like "TIMEOUT" would be > better. > > I think an explicit "_US" or "_MS" would better indicate the units. > > This is turning into a long tangent, but I'm not a huge fan of the > LINK_WAIT_* pattern where I have to look up the code that uses > LINK_WAIT_MAX_RETRIES and LINK_WAIT_USLEEP_MAX and do the math to see > what the actual timeout is. Obviously not fodder for *this* patch. Might as well do that indeed Konrad
