Please reject this Patch. I have made required changes which will remove PCI system's call from mptsas/mpt2sas/mpt3sas. I will be sending that patch to upstream. Currently waiting to do more testing on new patch. Thanks for constructive feedback. ` Kashyap > -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Desai, Kashyap > Sent: Wednesday, March 06, 2013 8:39 AM > To: Bjorn Helgaas > Cc: Joe Lawrence; linux-scsi@xxxxxxxxxxxxxxx; DL-MPT Fusion Linux; > Support; Reddy, Sreekanth; Nandigama, Nagalakshmi; James E.J. Bottomley; > linux-pci@xxxxxxxxxxxxxxx > Subject: RE: [PATCH 1/2] mptfusion, mpt2sas, mpt3sas: Don't remove dead > IOC PCI device > > > > > -----Original Message----- > > From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx] > > Sent: Wednesday, March 06, 2013 7:55 AM > > To: Desai, Kashyap > > Cc: Joe Lawrence; linux-scsi@xxxxxxxxxxxxxxx; DL-MPT Fusion Linux; > > Support; Reddy, Sreekanth; Nandigama, Nagalakshmi; James E.J. > > Bottomley; linux-pci@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH 1/2] mptfusion, mpt2sas, mpt3sas: Don't remove > > dead IOC PCI device > > > > On Tue, Mar 5, 2013 at 6:46 PM, Desai, Kashyap <Kashyap.Desai@xxxxxxx> > > wrote: > > > > > > > > >> -----Original Message----- > > >> From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx] > > >> Sent: Wednesday, March 06, 2013 4:43 AM > > >> To: Desai, Kashyap > > >> Cc: Joe Lawrence; linux-scsi@xxxxxxxxxxxxxxx; DL-MPT Fusion Linux; > > >> Support; Reddy, Sreekanth; Nandigama, Nagalakshmi; James E.J. > > >> Bottomley; linux-pci@xxxxxxxxxxxxxxx > > >> Subject: Re: [PATCH 1/2] mptfusion, mpt2sas, mpt3sas: Don't remove > > >> dead IOC PCI device > > >> > > >> [+cc linux-pci] > > >> > > >> On Mon, Mar 4, 2013 at 11:02 AM, Desai, Kashyap > > >> <Kashyap.Desai@xxxxxxx> > > >> wrote: > > >> > > > >> > > > >> >> -----Original Message----- > > >> >> From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > > >> >> owner@xxxxxxxxxxxxxxx] On Behalf Of Joe Lawrence > > >> >> Sent: Monday, March 04, 2013 9:26 PM > > >> >> To: linux-scsi@xxxxxxxxxxxxxxx > > >> >> Cc: DL-MPT Fusion Linux; Support; Reddy, Sreekanth; Nandigama, > > >> >> Nagalakshmi; James E.J. Bottomley; Bjorn Helgaas > > >> >> Subject: [PATCH 1/2] mptfusion, mpt2sas, mpt3sas: Don't remove > > >> >> dead IOC PCI device > > >> >> > > >> >> Device removal/addition is a PCI core function, not an HBA > > function. > > >> >> Calling pci_stop_and_remove_bus_device() from a SCSI LLD may > > >> >> introduce device removal races with PCI hotplug. Remove these > > >> >> calls from mptfusion, mpt2sas, and mpt3sas, but leave remaining > > >> >> dead IOC code in place that flushes outstanding commands and > > >> >> sets > > IOC state. > > >> > > > >> > Joe: I agree that only mptsas/mpt2sas/mpt3sas is calling " > > >> pci_stop_and_remove_bus_device" from LLD. If through sysfs we can > > >> hot add/remove the device, It would be OK to allow similar > > >> simulation from LLD. (In case it is really require.) I agree that > calling " > > >> pci_stop_and_remove_bus_device" is PCI subsystem's responsibility. > > >> > Please consider that finding bad IOC on field is very rare. > > >> > > > >> > In our case, user wants BAD IOC to be detected immediately (due > > >> > to > > >> performance and mission critical IOs) and it should be removed from > > >> the topology ASAP to allow other good IOC and connected topology to > > >> work well. > > >> > > >> It doesn't matter how rare bad IOCs are. But I certainly agree > > >> that when we do find a bad IOC, we want to detect it and stop using > > >> it as soon as possible. > > >> > > >> > With the new proposed change you posted with this patch half of > > >> > the > > >> problem still do not resolve. > > >> > > > >> > Driver set ioc->remove_host = 1 when bad IOC is detected, but > > >> > IOs to > > >> the connected topology will still continue to flood ( if we do not > > >> detach bad IOC from topology) and Scsi Mid layer be busy sending > > >> inactive IOs to the bad IOC, and IOs will be return to the OS with > > >> "DID_NO_CONNECT". > > >> > > > >> > So finally to release the topology from BAD IOC from OS is also > > >> equally important. This can be achieved either calling ".remove" > > >> entry point or what currently driver is doing "remove the IOC from > > >> PCI layer which will allow better cleanup. > > >> > > >> Joe's patch remove the call to pci_stop_and_remove_bus_device(), so > > >> the IOC will remain attached to the driver. What if he *did* call > > >> the driver's . remove() method instead of calling > > >> pci_stop_and_remove_bus_device()? Would that resolve your concern? > > >> If not, why not? > > > > > > I initially tried using Driver's .remove call instead of " > > pci_stop_and_remove_bus_device", but found inconsistent view from PCI > > layer and LLD will have its own disadvantage. > > > With that approach, PCI layer sill observe the bad HBA, but instance > > of the same is not visible at LLD. > > > > What's the problem with this? It is not a problem if the PCI device > > exists but no driver has claimed it. That situation exists very > > often, when the PCI core has enumerated a device but we haven't loaded > > a driver for it. > > > > > Finally, when someone try to remove module/Do some manual PCI bus > > > scan > > through sysfs functionality etc, LLD will not be able to handle those. > > > > I don't understand this. The mptsas driver can detach from one device > > while remaining attached to other similar devices. The driver can > > then be removed, and the fact that it is only attached to some of the > > devices is not a problem. Obviously, there could be mptsas defects > > that cause problems, but we should be able to fix those. > > > > Why does a manual PCI bus scan via sysfs cause an issue? > > PCI system still assume is_attacched for that HBA, but LLD has already > removed it. > I don't really remember where it crashed, but it was inconsistent if HBA > is removed only from LLD.. System crash after some times when user > perform some extra operations. > > I understood that, we need to find alternate for this case, instead of > calling "pci_stop_and_remove_bus_device".. > > But this Patch is not correct and working well. It will remove key > functionality from Driver. I will be sending one more patch which will > remove " pci_stop_and_remove_bus_device" from all three > mptsas/mpt2sas/mpt3sas Driver. > > We need to dump some Critical message for user about problem in their > setup and will recommend to remove bad HBA and restart the machine, > instead of expecting normal functionality even after detecting bad HBA. > > Let me work on this and will revert back. > > > > > > Calling .remove entry point from Driver and still keeping instance > > > at > > PCI layer will create inconsistency between two layers. > > > > > >> > > >> I would really like to get rid of pci_stop_and_remove_bus_device() > > >> in drivers. I don't think there's anything special about > > >> mptsas/mpt2sas/mpt3sas that makes it useful for these drivers but > > >> not others. > > > > > > I agree that calling " pci_stop_and_remove_bus_device" should be the > > last option, but as of now I found that is a safest way to achieve > > functionality. > > > > What specific functionality are you trying to achieve? > > We want less destruction to working system because of single BAD HBA. > > > > > > If you don't want to call the driver's .remove() method, you can keep > > the driver bound to the device but just disconnect the device from the > > SCSI midlayer. Then the PCI device exists, the LLD is still bound to > > it, but nobody will be able to use it. > > > > > It is nothing special about mptsas/mpt2sas/mpt3sas related. > > > > > >> > > >> Bjorn > > >> > > >> >> Signed-off-by: Joe Lawrence <joe.lawrence@xxxxxxxxxxx> > > >> >> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > >> >> Cc: James E.J. Bottomley <JBottomley@xxxxxxxxxxxxx> > > >> >> Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@xxxxxxx> > > >> >> Cc: Sreekanth Reddy <Sreekanth.Reddy@xxxxxxx> > > >> >> Cc: support@xxxxxxx > > >> >> Cc: DL-MPTFusionLinux@xxxxxxx > > >> >> Cc: linux-scsi@xxxxxxxxxxxxxxx > > >> >> --- > > >> >> drivers/message/fusion/mptbase.c | 41 +--------------------- > -- > > --- > > >> --- > > >> >> ------ > > >> >> drivers/scsi/mpt2sas/mpt2sas_base.c | 42 > > >> >> ++---------------------------- > > >> >> ------- > > >> >> drivers/scsi/mpt3sas/mpt3sas_base.c | 40 > > >> >> ++---------------------------- > > >> >> ----- > > >> >> 3 files changed, 5 insertions(+), 118 deletions(-) > > >> >> > > >> >> diff --git a/drivers/message/fusion/mptbase.c > > >> >> b/drivers/message/fusion/mptbase.c > > >> >> index fb69baa..28a421d 100644 > > >> >> --- a/drivers/message/fusion/mptbase.c > > >> >> +++ b/drivers/message/fusion/mptbase.c > > >> >> @@ -63,7 +63,6 @@ > > >> >> #ifdef CONFIG_MTRR > > >> >> #include <asm/mtrr.h> > > >> >> #endif > > >> >> -#include <linux/kthread.h> > > >> >> #include <scsi/scsi_host.h> > > >> >> > > >> >> #include "mptbase.h" > > >> >> @@ -328,31 +327,6 @@ mpt_is_discovery_complete(MPT_ADAPTER *ioc) > > >> >> > > >> >> > > >> >> /** > > >> >> - * mpt_remove_dead_ioc_func - kthread context to remove dead > > >> >> ioc > > >> >> - * @arg: input argument, used to derive ioc > > >> >> - * > > >> >> - * Return 0 if controller is removed from pci subsystem. > > >> >> - * Return -1 for other case. > > >> >> - */ > > >> >> -static int mpt_remove_dead_ioc_func(void *arg) -{ > > >> >> - MPT_ADAPTER *ioc = (MPT_ADAPTER *)arg; > > >> >> - struct pci_dev *pdev; > > >> >> - > > >> >> - if ((ioc == NULL)) > > >> >> - return -1; > > >> >> - > > >> >> - pdev = ioc->pcidev; > > >> >> - if ((pdev == NULL)) > > >> >> - return -1; > > >> >> - > > >> >> - pci_stop_and_remove_bus_device(pdev); > > >> >> - return 0; > > >> >> -} > > >> >> - > > >> >> - > > >> >> - > > >> >> -/** > > >> >> * mpt_fault_reset_work - work performed on workq after ioc > > fault > > >> >> * @work: input argument, used to derive ioc > > >> >> * > > >> >> @@ -366,7 +340,6 @@ mpt_fault_reset_work(struct work_struct > *work) > > >> >> int rc; > > >> >> unsigned long flags; > > >> >> MPT_SCSI_HOST *hd; > > >> >> - struct task_struct *p; > > >> >> > > >> >> if (ioc->ioc_reset_in_progress || !ioc->active) > > >> >> goto out; > > >> >> @@ -380,25 +353,13 @@ mpt_fault_reset_work(struct work_struct > > *work) > > >> >> /* > > >> >> * Call mptscsih_flush_pending_cmds callback so > > >> >> that > > we > > >> >> * flush all pending commands back to OS. > > >> >> - * This call is required to aovid deadlock at > block > > >> layer. > > >> >> + * This call is required to avoid deadlock at > > >> >> + block > > >> layer. > > >> >> * Dead IOC will fail to do diag reset,and this > > >> >> call is > > >> safe > > >> >> * since dead ioc will never return any command > > >> >> back from HW. > > >> >> */ > > >> >> hd = shost_priv(ioc->sh); > > >> >> ioc->schedule_dead_ioc_flush_running_cmds(hd); > > >> >> > > >> >> - /*Remove the Dead Host */ > > >> >> - p = kthread_run(mpt_remove_dead_ioc_func, ioc, > > >> >> - "mpt_dead_ioc_%d", ioc->id); > > >> >> - if (IS_ERR(p)) { > > >> >> - printk(MYIOC_s_ERR_FMT > > >> >> - "%s: Running mpt_dead_ioc thread > > failed > > >> !\n", > > >> >> - ioc->name, __func__); > > >> >> - } else { > > >> >> - printk(MYIOC_s_WARN_FMT > > >> >> - "%s: Running mpt_dead_ioc thread > > >> success !\n", > > >> >> - ioc->name, __func__); > > >> >> - } > > >> >> return; /* don't rearm timer */ > > >> >> } > > >> >> > > >> >> diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c > > >> >> b/drivers/scsi/mpt2sas/mpt2sas_base.c > > >> >> index ffd85c5..a97d10c 100644 > > >> >> --- a/drivers/scsi/mpt2sas/mpt2sas_base.c > > >> >> +++ b/drivers/scsi/mpt2sas/mpt2sas_base.c > > >> >> @@ -57,7 +57,6 @@ > > >> >> #include <linux/sort.h> > > >> >> #include <linux/io.h> > > >> >> #include <linux/time.h> > > >> >> -#include <linux/kthread.h> > > >> >> #include <linux/aer.h> > > >> >> > > >> >> #include "mpt2sas_base.h" > > >> >> @@ -115,29 +114,6 @@ module_param_call(mpt2sas_fwfault_debug, > > >> >> _scsih_set_fwfault_debug, > > >> >> param_get_int, &mpt2sas_fwfault_debug, 0644); > > >> >> > > >> >> /** > > >> >> - * mpt2sas_remove_dead_ioc_func - kthread context to remove > > >> >> dead ioc > > >> >> - * @arg: input argument, used to derive ioc > > >> >> - * > > >> >> - * Return 0 if controller is removed from pci subsystem. > > >> >> - * Return -1 for other case. > > >> >> - */ > > >> >> -static int mpt2sas_remove_dead_ioc_func(void *arg) -{ > > >> >> - struct MPT2SAS_ADAPTER *ioc = (struct > > MPT2SAS_ADAPTER > > >> *)arg; > > >> >> - struct pci_dev *pdev; > > >> >> - > > >> >> - if ((ioc == NULL)) > > >> >> - return -1; > > >> >> - > > >> >> - pdev = ioc->pdev; > > >> >> - if ((pdev == NULL)) > > >> >> - return -1; > > >> >> - pci_stop_and_remove_bus_device(pdev); > > >> >> - return 0; > > >> >> -} > > >> >> - > > >> >> - > > >> >> -/** > > >> >> * _base_fault_reset_work - workq handling ioc fault conditions > > >> >> * @work: input argument, used to derive ioc > > >> >> * Context: sleep. > > >> >> @@ -152,7 +128,6 @@ _base_fault_reset_work(struct work_struct > > *work) > > >> >> unsigned long flags; > > >> >> u32 doorbell; > > >> >> int rc; > > >> >> - struct task_struct *p; > > >> >> > > >> >> spin_lock_irqsave(&ioc->ioc_reset_in_progress_lock, > flags); > > >> >> if (ioc->shost_recovery) > > >> >> @@ -166,29 +141,16 @@ _base_fault_reset_work(struct work_struct > > >> >> *work) > > >> >> > > >> >> /* > > >> >> * Call _scsih_flush_pending_cmds callback so that > > >> >> we flush all > > >> >> - * pending commands back to OS. This call is > > required > > >> to > > >> >> aovid > > >> >> + * pending commands back to OS. This call is > > >> >> + required to > > >> >> avoid > > >> >> * deadlock at block layer. Dead IOC will fail to > > >> >> do diag reset, > > >> >> * and this call is safe since dead ioc will never > > >> >> return any > > >> >> * command back from HW. > > >> >> */ > > >> >> ioc->schedule_dead_ioc_flush_running_cmds(ioc); > > >> >> /* > > >> >> - * Set remove_host flag early since kernel thread > > will > > >> >> - * take some time to execute. > > >> >> + * Indicate to scsi callbacks that the host has > > >> >> + been > > >> >> removed. > > >> >> */ > > >> >> ioc->remove_host = 1; > > >> >> - /*Remove the Dead Host */ > > >> >> - p = kthread_run(mpt2sas_remove_dead_ioc_func, ioc, > > >> >> - "mpt2sas_dead_ioc_%d", ioc->id); > > >> >> - if (IS_ERR(p)) { > > >> >> - printk(MPT2SAS_ERR_FMT > > >> >> - "%s: Running mpt2sas_dead_ioc thread > failed > > >> !!!!\n", > > >> >> - ioc->name, __func__); > > >> >> - } else { > > >> >> - printk(MPT2SAS_ERR_FMT > > >> >> - "%s: Running mpt2sas_dead_ioc thread > success > > >> !!!!\n", > > >> >> - ioc->name, __func__); > > >> >> - } > > >> >> > > >> >> return; /* don't rearm timer */ > > >> >> } > > >> >> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c > > >> >> b/drivers/scsi/mpt3sas/mpt3sas_base.c > > >> >> index 04f8010..24fd122 100644 > > >> >> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c > > >> >> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c > > >> >> @@ -57,7 +57,6 @@ > > >> >> #include <linux/dma-mapping.h> > > >> >> #include <linux/io.h> > > >> >> #include <linux/time.h> > > >> >> -#include <linux/kthread.h> > > >> >> #include <linux/aer.h> > > >> >> > > >> >> > > >> >> @@ -111,28 +110,6 @@ module_param_call(mpt3sas_fwfault_debug, > > >> >> _scsih_set_fwfault_debug, > > >> >> param_get_int, &mpt3sas_fwfault_debug, 0644); > > >> >> > > >> >> /** > > >> >> - * mpt3sas_remove_dead_ioc_func - kthread context to remove > > >> >> dead ioc > > >> >> - * @arg: input argument, used to derive ioc > > >> >> - * > > >> >> - * Return 0 if controller is removed from pci subsystem. > > >> >> - * Return -1 for other case. > > >> >> - */ > > >> >> -static int mpt3sas_remove_dead_ioc_func(void *arg) -{ > > >> >> - struct MPT3SAS_ADAPTER *ioc = (struct MPT3SAS_ADAPTER > *)arg; > > >> >> - struct pci_dev *pdev; > > >> >> - > > >> >> - if ((ioc == NULL)) > > >> >> - return -1; > > >> >> - > > >> >> - pdev = ioc->pdev; > > >> >> - if ((pdev == NULL)) > > >> >> - return -1; > > >> >> - pci_stop_and_remove_bus_device(pdev); > > >> >> - return 0; > > >> >> -} > > >> >> - > > >> >> -/** > > >> >> * _base_fault_reset_work - workq handling ioc fault conditions > > >> >> * @work: input argument, used to derive ioc > > >> >> * Context: sleep. > > >> >> @@ -147,7 +124,6 @@ _base_fault_reset_work(struct work_struct > > *work) > > >> >> unsigned long flags; > > >> >> u32 doorbell; > > >> >> int rc; > > >> >> - struct task_struct *p; > > >> >> > > >> >> > > >> >> spin_lock_irqsave(&ioc->ioc_reset_in_progress_lock, > > >> >> flags); @@ > > >> >> - > > >> >> 162,28 +138,16 @@ _base_fault_reset_work(struct work_struct > > >> >> *work) > > >> >> > > >> >> /* > > >> >> * Call _scsih_flush_pending_cmds callback so that > > >> >> we flush all > > >> >> - * pending commands back to OS. This call is > > required > > >> to > > >> >> aovid > > >> >> + * pending commands back to OS. This call is > > >> >> + required to > > >> >> avoid > > >> >> * deadlock at block layer. Dead IOC will fail to > > >> >> do diag reset, > > >> >> * and this call is safe since dead ioc will never > > >> >> return any > > >> >> * command back from HW. > > >> >> */ > > >> >> ioc->schedule_dead_ioc_flush_running_cmds(ioc); > > >> >> /* > > >> >> - * Set remove_host flag early since kernel thread > > will > > >> >> - * take some time to execute. > > >> >> + * Indicate to scsi callbacks that the host has > > >> >> + been > > >> >> removed. > > >> >> */ > > >> >> ioc->remove_host = 1; > > >> >> - /*Remove the Dead Host */ > > >> >> - p = kthread_run(mpt3sas_remove_dead_ioc_func, ioc, > > >> >> - "mpt3sas_dead_ioc_%d", ioc->id); > > >> >> - if (IS_ERR(p)) > > >> >> - pr_err(MPT3SAS_FMT > > >> >> - "%s: Running mpt3sas_dead_ioc thread > failed > > >> !!!!\n", > > >> >> - ioc->name, __func__); > > >> >> - else > > >> >> - pr_err(MPT3SAS_FMT > > >> >> - "%s: Running mpt3sas_dead_ioc thread > success > > >> !!!!\n", > > >> >> - ioc->name, __func__); > > >> >> return; /* don't rearm timer */ > > >> >> } > > >> >> > > >> >> -- > > >> >> 1.8.1.2 > > >> >> > > >> >> -- > > >> >> 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 -- 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
