From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nicholas A. Bellinger" Subject: [PATCH v2 00/11] Drop host_lock usage from scsi_dispatch_cmd() Date: Fri, 17 Sep 2010 11:21:37 -0700 Message-ID: <1284747697-20840-1-git-send-email-nab@linux-iscsi.org> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-scsi , linux-kernel , Vasu Dev , Tim Chen , Andi Kleen Cc: James Smart , Andrew Vasquez , FUJITA Tomonori , Hannes Reinecke , Joe Eykholt , Christoph Hellwig , Nicholas Bellinger List-Id: linux-scsi@vger.kernel.org From: Nicholas Bellinger Greetings all, This series contains the second round of a whole-sale conversion for completely dropping struct Scsi_Host->host_lock usage within scsi_dispatch_cmd() for the ML internal scsi_cmd_get_serial() and external SHT->queuecommand() LLD callers. The main changes from comments from v1 -> v2 are: *) Make scsi_cmd_get_serial() use atomic_t and disable it's usage by default. *) Drop struct Scsi_Host->host_lock usage in scsi_dispatch_cmd() For the v2 series, patch #1 converts struct Scsi_Host->cmd_serial_number to atomic_t and adds struct Scsi_Host->use_serial_number to enabled usage. This patch also follows Joe Eykholt suggestion of using a +2 for each scsi_cmd_get_serial() to ensure that the counter always wraps to a non-zero value. Patch #2 completely removes host_lock usage from scsi_dispatch_cmd(). Patch #3 -> #6 remove the legacy host_lock lock() -> do_work() -> unlock() optimization from generic libiscsi, libsas, libfc and libata ->queuecommand() callers respectively. And patches #7 -> #11 do the same conversion legacy host_lock lock() -> do_work() -> unlock() for lpfc, qla4xxx, qla2xxx, fnic, and buslogic LLDs specific ->queuecommand() callers. There may still be more LLDs which use this optimization, so please let me know if there is another piece of SHT->queuecommand() caller code that does this legacy optimization not in this list that need to be updated. I will be sure to CC the right driver maintainers and CC linux-scsi as I come across any more conversions. Many thanks to James Bottomley, Andi Keen, Joe Eykholt, Vasu Dev and Tim Chen for their code and comments! Signed-off-by: Nicholas A. Bellinger Nicholas Bellinger (11): scsi: Convert struct Scsi_Host->cmd_serial_number to atomic_t scsi: Drop struct Scsi_Host->host_lock usage in scsi_dispatch_cmd() libiscsi: Remove host_lock unlock() + lock() from iscsi_queuecommand() libsas: Remove host_lock unlock() + lock() from sas_queuecommand() libfc: Remove host_lock unlock() + lock() from fc_queuecommand() libata: Remove host_lock unlock() + lock() from ata_scsi_queuecmd() lpfc: Remove host_lock unlock() + lock() from lpfc_queuecommand() qla4xxx: Remove host_lock unlock() + lock() from qla4xxx_queuecommand() qla2xxx: Remove host_lock unlock() + lock() from qla2xxx_queuecommand() fnic: Remove host_lock unlock() + lock() from fnic_queuecommand() buslogic: Remove host_lock unlock() + lock() from BusLogic_QueueCommand() drivers/ata/libata-scsi.c | 2 -- drivers/scsi/BusLogic.c | 4 ---- drivers/scsi/fnic/fnic_scsi.c | 9 --------- drivers/scsi/hosts.c | 4 ++++ drivers/scsi/libfc/fc_fcp.c | 5 +---- drivers/scsi/libiscsi.c | 4 ---- drivers/scsi/libsas/sas_scsi_host.c | 5 ----- drivers/scsi/lpfc/lpfc_scsi.c | 2 -- drivers/scsi/qla2xxx/qla_os.c | 7 ++----- drivers/scsi/qla4xxx/ql4_os.c | 8 +------- drivers/scsi/scsi.c | 17 +++++++++++------ include/scsi/scsi_host.h | 8 +++++--- 12 files changed, 24 insertions(+), 51 deletions(-) -- 1.7.2.3