Nicholas, Thanks for put it back. This set (to NULL) is in original megasas_get_cmd src. Can you share your testing with us (how much test you did in lock_less kernel)? We don't do any test with this kernel.. Thanks, Bo Yang -----Original Message----- From: Nicholas A. Bellinger [mailto:nab@xxxxxxxxxxxxxxx] Sent: Tuesday, November 30, 2010 5:06 PM To: Yang, Bo Cc: linux-scsi; Hannes Reinecke; Christoph Hellwig; James Bottomley; Daftardar, Jayant Subject: RE: [PATCH 0/3] megaraid_sas: Convert to host_lock less w/ interrupts disabled internally On Tue, 2010-11-30 at 13:21 -0800, Nicholas A. Bellinger wrote: > On Mon, 2010-11-29 at 23:26 -0700, Yang, Bo wrote: > > Nicholas, > > > > Thanks for your patches (patches 1 -3). We need to build the driver and provide it to our testing team to do > > the full verification on lock_less kernel. > > > The patch 2 and patch 3 changed the driver's major routines (I/O, get/return cmds routines and OCR routine). > > I will keep update after we did the internal patch re-view for those changes as well as the testing team > > give us the report. > > > > Great, thanks for moving forward on the lock_less conversion.. Please > let me know if you have any other questions. > > > By the way, can you send me the full link of: lio-core-2.6.git/lock_less-LLDs-for-38-v2? I am try to understand the changes for patch 3 > > > The patch #3 in full context is available here: > > http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=blob;f=drivers/scsi/megaraid/megaraid_sas.c;h=c42e1e4ef8c9923d9a930fa631f8d65455afadd6;hb=lock_less-LLDs-for-38-v2 > > Thanks! > > --nab > > Hi Bo, I also noticed that __megasas_get_cmd() still needs the initial *cmd = NULL assignment. Pushing the following into lock_less-LLDs-for-38-v2 now: Subject: [PATCH] megaraid_sas: Add NULL assignment in __megasas_get_cmd() This patch changes the initial struct megasas_cmd *cmd to NULL, which follows the pre lock_less conversion code. Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> --- drivers/scsi/megaraid/megaraid_sas.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c index c42e1e4..be956a5 100644 --- a/drivers/scsi/megaraid/megaraid_sas.c +++ b/drivers/scsi/megaraid/megaraid_sas.c @@ -131,7 +131,7 @@ megasas_complete_cmd(struct megasas_instance *instance, struct megasas_cmd *cmd, static struct megasas_cmd * __megasas_get_cmd(struct megasas_instance *instance) { - struct megasas_cmd *cmd; + struct megasas_cmd *cmd = NULL; if (!list_empty(&instance->cmd_pool)) { cmd = list_entry((&instance->cmd_pool)->next, -- 1.7.2.3 Thanks! --nab > > + struct megasas_cmd *cmd; > > unsigned long flags; > > - struct megasas_cmd *cmd = NULL; > > > > And > > > > +megasas_get_cmd(struct megasas_instance *instance) { > > + struct megasas_cmd *cmd; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&instance->cmd_pool_lock, flags); > > + cmd = __megasas_get_cmd(instance); > > spin_unlock_irqrestore(&instance->cmd_pool_lock, flags); > > + > > return cmd; > > } > > > > Regards, > > > > Bo Yang > > > > -----Original Message----- > > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi-owner@xxxxxxxxxxxxxxx] On Behalf Of Nicholas A. Bellinger > > Sent: Sunday, November 28, 2010 2:18 AM > > To: linux-scsi; Hannes Reinecke; Yang, Bo > > Cc: Christoph Hellwig; James Bottomley; Nicholas Bellinger > > Subject: [PATCH 0/3] megaraid_sas: Convert to host_lock less w/ interrupts disabled internally > > > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > Greetings Hannes, Bo and Co, > > > > This series converts megaraid_sas to run in modern host_lock-less mode > > for >= .37-rc3+ with interrupts disabled internally around megasas_instance->hba_lock. > > This series is currently living in lio-core-2.6.git/lock_less-LLDs-for-38-v2, > > and is intended for .38 mainline code. > > > > The first patch adds a handful of missing barriers around instance->fw_outstanding > > usage w/ atomic_add() and atomic_dec(). > > > > The second converts instance->issuepend_done to an atomic_t, along with > > the necessary assignments in order to run w/ Scsi_Host->host_lock, and > > without instance->hba_lock. > > > > The third patch does the actual conversion, and adds a __megasas_get_cmd() > > usased by megasas_queue_command() w/ instance->hba_lock, along with > > being held for megasas_build_ldio() and megasas_build_dcdb() in order > > to locate the proper frame for struct megasas_cmd. This is really the > > one major change in order to get host_lock-less to function with interrupts > > disabled around hba_lock. > > > > So far this has been tested with Hannes's QEMU 8708EM2 HBA emulation with > > TCM_Loop backends using SG_IO from KVM host in a paired Host/Guest .37-rc3 > > environment. This has not been tested on real silicon yet, but I believe > > this series should be working there as well. > > > > Comments are welcome, thanks! > > > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> > > > > Nicholas Bellinger (3): > > megaraid_sas: Add smp_mb__after_atomic_*() for > > instance->fw_outstanding > > megaraid_sas: Convert instance->issuepend_done to atomic_t > > megaraid_sas: Convert SHT->queuecommand() to run host_lock-less > > > > drivers/scsi/megaraid/megaraid_sas.c | 84 ++++++++++++++++++++++----------- > > drivers/scsi/megaraid/megaraid_sas.h | 2 +- > > 2 files changed, 57 insertions(+), 29 deletions(-) > > > > -- > 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 -- 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
