From: Sreekanth Reddy [mailto:sreekanth.reddy@xxxxxxxxxxxxx] Sent: Tuesday, September 08, 2015 5:26 PM To: Nicholas A. Bellinger Cc: linux-scsi; linux-kernel; James Bottomley; Calvin Owens; Christoph Hellwig; MPT-FusionLinux.pdl; kernel-team; Nicholas Bellinger; Chaitra Basappa Subject: Re: [PATCH-v2 1/2] mpt3sas: Refcount sas_device objects and fix unsafe list usage On Sun, Aug 30, 2015 at 1:24 PM, Nicholas A. Bellinger <nab@xxxxxxxxxxxxx> wrote: > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > 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. > > This patch is a port of Calvin's PATCH-v4 for mpt2sas code, atop > mpt3sas changes in scsi.git/for-next. > > Cc: Calvin Owens <calvinowens@xxxxxx> > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> > Cc: Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxxx> > Cc: MPT-FusionLinux.pdl <MPT-FusionLinux.pdl@xxxxxxxxxxxxx> > Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > --- > drivers/scsi/mpt3sas/mpt3sas_base.h | 25 +- > drivers/scsi/mpt3sas/mpt3sas_scsih.c | 479 > +++++++++++++++++++++---------- > drivers/scsi/mpt3sas/mpt3sas_transport.c | 18 +- > 3 files changed, 364 insertions(+), 158 deletions(-) > > @@ -2763,7 +2874,7 @@ _scsih_block_io_device(struct MPT3SAS_ADAPTER *ioc, > u16 handle) > struct scsi_device *sdev; > struct _sas_device *sas_device; > [Sreekanth] Here sas_device_lock spin lock needs to be acquired before calling __mpt3sas_get_sdev_by_addr() function. [Chaitra]Here instead of calling " __mpt3sas_get_sdev_by_handle()" function calling "mpt3sas_get_sdev_by_handle()" function will fixes "invalid page access" type of kernel panic > - sas_device = _scsih_sas_device_find_by_handle(ioc, handle); > + sas_device = __mpt3sas_get_sdev_by_handle(ioc, handle); > if (!sas_device) > return; > > @@ -2779,6 +2890,8 @@ _scsih_block_io_device(struct MPT3SAS_ADAPTER *ioc, > u16 handle) > continue; > _scsih_internal_device_block(sdev, sas_device_priv_data); > } > + > + sas_device_put(sas_device); > } > Regards, Chaitra -- 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
