On 09/06/2015 12:34 AM, Sagi Grimberg wrote: > On 9/5/2015 11:44 PM, Lee Duncan wrote: >> Each Scsi_host instance gets a host number starting >> at 0, but this was implemented with an atomic integer, >> and rollover wasn't considered. Another problem with >> this design is that scsi host numbers used by iscsi >> are never reused, thereby making rollover more likely. >> This patch converts Scsi_host instances to use idr >> to manage their instance numbers and to simplify >> instance number to pointer lookups. >> >> This also means that host instance numbers will be >> reused, when available. >> >> Signed-off-by: Lee Duncan <lduncan@xxxxxxxx> >> --- >> drivers/scsi/hosts.c | 59 >> +++++++++++++++++++++++++--------------------------- >> 1 file changed, 28 insertions(+), 31 deletions(-) >> >> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c >> index 8bb173e01084..1127a50e5942 100644 >> --- a/drivers/scsi/hosts.c >> +++ b/drivers/scsi/hosts.c >> @@ -33,7 +33,7 @@ >> #include <linux/transport_class.h> >> #include <linux/platform_device.h> >> #include <linux/pm_runtime.h> >> - >> +#include <linux/idr.h> >> #include <scsi/scsi_device.h> >> #include <scsi/scsi_host.h> >> #include <scsi/scsi_transport.h> >> @@ -41,8 +41,8 @@ >> #include "scsi_priv.h" >> #include "scsi_logging.h" >> >> - >> -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for >> next new host */ >> +static DEFINE_SPINLOCK(host_index_lock); >> +static DEFINE_IDR(host_index_idr); >> >> >> static void scsi_host_cls_release(struct device *dev) >> @@ -337,6 +337,10 @@ static void scsi_host_dev_release(struct device >> *dev) >> >> kfree(shost->shost_data); >> >> + spin_lock(&host_index_lock); >> + idr_remove(&host_index_idr, shost->host_no); >> + spin_unlock(&host_index_lock); >> + > > Did you change your mind on having host_[get|put]_idx() helpers? No. As I said on the description: > A separate patch sequence follows which will add helper routines > for the ida index functions. I'll be sending out that patch series today (I hope). I *do* believe it would be useful to add some ida helper routines, since callers of these routines seem mostly to use a uniform calling sequence. But even so some of the callers do things differently enough so that I was not comfortable changing them to use the helper routines. But the "idr" routines, i.e. the ones that manage both an index *and* a pointer, which are the ones I'm using in hosts.c, are not called so uniformly, so helper routines did not seem like a good idea. -- Lee Duncan -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
