Hi Calvin, On Thu, 2015-08-13 at 18:48 -0700, Calvin Owens wrote: > These objects can be referenced concurrently throughout the driver, we > need a way to make sure threads can't delete them out from under each > other. This patch adds the refcount, and refactors the code to use it. > > Additionally, we cannot iterate over the sas_device_list without > holding the lock, or we risk corrupting random memory if items are > added or deleted as we iterate. This patch refactors _scsih_probe_sas() > to use the sas_device_list in a safe way. > > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> > Cc: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> > Cc: Joe Lawrence <joe.lawrence@xxxxxxxxxxx> > Signed-off-by: Calvin Owens <calvinowens@xxxxxx> > --- > Changes in v4: > * Fix lack of put() in non-SATA case in _scsih_change_queue_depth() > * Fix lack of put() in the non-error case in _scsih_check_device() > * Add missing put() at bottom of _scsih_add_device() > * Add put for ->hostdata pointer in _scsih_target_destroy() for the > get() in _scsih_target_alloc() > > Changes in v3: > * Drop the sas_device_lock while enabling devices, and leave the > sas_device object on the list, since it may need to be looked up there > while it is being enabled. > * Drop put() in _scsih_add_device(), because the ->hostdata now keeps a > reference (this was an oversight in v2). > * Be consistent about calling sas_device_put() while holding the > sas_device_lock where feasible. > * Take and assert_spin_locked() on the sas_device_lock from the newly > added __get_sdev_from_target(), add wrapper similar to other lookups > for callers which do not explicitly take the lock. > > Changes in v2: > * Squished patches 1-3 into this one > * s/BUG_ON(!spin_is_locked/assert_spin_locked/g > * Store a pointer to the sas_device object in ->hostdata, to eliminate > the need for several lookups on the lists. > > drivers/scsi/mpt2sas/mpt2sas_base.h | 22 +- > drivers/scsi/mpt2sas/mpt2sas_scsih.c | 480 +++++++++++++++++++++---------- > drivers/scsi/mpt2sas/mpt2sas_transport.c | 12 +- > 3 files changed, 360 insertions(+), 154 deletions(-) > Looks good. Reviewed-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> -- 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
