Messages in this thread | | | Date | Tue, 28 Mar 2023 19:39:05 -0400 | Subject | Re: [PATCH v3 02/11] scsi: scsi_debug: Don't iter all shosts in clear_luns_changed_on_target() | From | Douglas Gilbert <> |
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On 2023-03-27 03:43, John Garry wrote: > In clear_luns_changed_on_target(), we iter all devices for all shosts to > conditionally clear the SDEBUG_UA_LUNS_CHANGED flag in the per-device > uas_bm. > > One condition to see whether we clear the flag is to test whether the host > for the device under consideration is the same as the matching device's > (devip) host. This check will only ever pass for devices for the same > shost, so only iter the devices for the matching device shost. > > We can now drop the spinlock'ing of the sdebug_host_list_lock in the same > function. This will allow us to use a mutex instead of the spinlock for > the global shost lock, as clear_luns_changed_on_target() could be called > in non-blocking context, in scsi_debug_queuecommand() -> make_ua() -> > clear_luns_changed_on_target() (which is why required a spinlock). > > Signed-off-by: John Garry <john.g.garry@oracle.com> Acked-by: Douglas Gilbert <dgilbert@interlog.com
Thanks.
> --- > drivers/scsi/scsi_debug.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index 782515abca2c..eba6eca81e84 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -1063,18 +1063,15 @@ static void all_config_cdb_len(void) > > static void clear_luns_changed_on_target(struct sdebug_dev_info *devip) > { > - struct sdebug_host_info *sdhp; > + struct sdebug_host_info *sdhp = devip->sdbg_host; > struct sdebug_dev_info *dp; > > - spin_lock(&sdebug_host_list_lock); > - list_for_each_entry(sdhp, &sdebug_host_list, host_list) { > - list_for_each_entry(dp, &sdhp->dev_info_list, dev_list) { > - if ((devip->sdbg_host == dp->sdbg_host) && > - (devip->target == dp->target)) > - clear_bit(SDEBUG_UA_LUNS_CHANGED, dp->uas_bm); > + list_for_each_entry(dp, &sdhp->dev_info_list, dev_list) { > + if ((devip->sdbg_host == dp->sdbg_host) && > + (devip->target == dp->target)) { > + clear_bit(SDEBUG_UA_LUNS_CHANGED, dp->uas_bm); > } > } > - spin_unlock(&sdebug_host_list_lock); > } > > static int make_ua(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
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