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- 17 May, 2023 1 commit
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Kees Cook authored
In the ongoing effort to replace all fake flexible arrays with true flexible arrays, replace the sge32, sge64, and sge_skinny members of union megasas_sgl with true flexible arrays. No binary differences are seen after this change; sizes were already being manually calculated using the member struct sizes directly. Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumit Saxena <sumit.saxena@broadcom.com> Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: megaraidlinux.pdl@broadcom.com Cc: linux-scsi@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230511220957.never.919-kees@kernel.orgSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 06 Mar, 2023 3 commits
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Chandrakanth Patil authored
Update driver version. Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Link: https://lore.kernel.org/r/20230302105342.34933-4-chandrakanth.patil@broadcom.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
In kdump kernel mode, the driver works in reduced functionality mode with some features disabled such as reduced MSI-X count and RDPQ disabled, etc. However, the firmware is not aware of this mode in some cases, which results in undefined behavior. To address this, the driver informs the firmware about the kdump mode through MPI capabilities bit during driver initialization. This allows firmware to adjust its behavior accordingly. Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Link: https://lore.kernel.org/r/20230302105342.34933-3-chandrakanth.patil@broadcom.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
The firmware only supports Logical Disk IDs up to 240 and LD ID 255 (0xFF) is reserved for deleted LDs. However, in some cases, firmware was assigning LD ID 254 (0xFE) to deleted LDs and this was causing the driver to mark the wrong disk as deleted. This in turn caused the wrong disk device to be taken offline by the SCSI midlayer. To address this issue, limit the LD ID range from 255 to 240. This ensures the deleted LD ID is properly identified and removed by the driver without accidently deleting any valid LDs. Fixes: ae6874ba ("scsi: megaraid_sas: Early detection of VD deletion through RaidMap update") Reported-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Link: https://lore.kernel.org/r/20230302105342.34933-2-chandrakanth.patil@broadcom.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 07 Apr, 2022 1 commit
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Chandrakanth patil authored
The megaraid_sas driver supports single LUN for RAID devices. That is LUN 0. All other LUNs are unsupported. When a device scan on a logical target with invalid LUN number is invoked through sysfs, that target ends up getting removed. Add LUN ID validation in the slave destroy function to avoid the target deletion. Link: https://lore.kernel.org/r/20220324094711.48833-1-chandrakanth.patil@broadcom.comSigned-off-by: Chandrakanth patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 23 Feb, 2022 1 commit
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Bart Van Assche authored
Set .cmd_size in the SCSI host template instead of using the SCSI pointer from struct scsi_cmnd. This patch prepares for removal of the SCSI pointer from struct scsi_cmnd. Link: https://lore.kernel.org/r/20220218195117.25689-34-bvanassche@acm.orgReviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 05 Oct, 2021 1 commit
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Sumit Saxena authored
Link: https://lore.kernel.org/r/20210929124022.24605-4-sumit.saxena@broadcom.comSigned-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 02 Jun, 2021 2 commits
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Chandrakanth Patil authored
Link: https://lore.kernel.org/r/20210528131307.25683-6-chandrakanth.patil@broadcom.comSigned-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Kashyap Desai authored
Consider the case where a VD is deleted and the targetID of that VD is assigned to a newly created VD. If the sequence of deletion/addition of VD happens very quickly there is a possibility that second event (VD add) occurs even before the driver processes the first event (VD delete). As event processing is done in deferred context the device list remains the same (but targetID is re-used) so driver will not learn the VD deletion/additon. I/Os meant for the older VD will be directed to new VD which may lead to data corruption. Make driver detect the deleted VD as soon as possible based on the RaidMap update and block further I/O to that device. Link: https://lore.kernel.org/r/20210528131307.25683-4-chandrakanth.patil@broadcom.comReported-by: kernel test robot <lkp@intel.com> Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 04 Mar, 2021 2 commits
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Kashyap Desai authored
Implement mq_poll interface support in megaraid_sas. This feature requires shared host tag support in kernel and driver. The driver can work in non-IRQ mode which means there will not be any MSI-x vector associated for poll_queues. The MegaRAID hardware has a single submission queue and multiple reply queues. However, using the shared host tagset support will enable the driver to simulate multiple hardware queues. Change driver to allocate some extra reply queues which will be marked as poll_queues. These poll_queues will not have associated MSI-x vectors. All I/O completions on these queues will be done through the IOPOLL interface. megaraid_sas with 8 poll_queues and using the io_uring hiprio=1 setting can reach 3.2M IOPS with zero interrupts generated by the hardware. The IOPOLL feature can be enabled using module parameter poll_queues. Link: https://lore.kernel.org/r/20210215074048.19424-3-kashyap.desai@broadcom.com Cc: sumit.saxena@broadcom.com Cc: chandrakanth.patil@broadcom.com Cc: linux-block@vger.kernel.org Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Kashyap Desai authored
Use local tracking of per-sdev outstanding command since sdev_busy in SCSI mid layer is improved for performance reason using sbitmap (earlier it was atomic variable). Link: https://lore.kernel.org/r/20210122023317.687987-11-ming.lei@redhat.com Cc: Omar Sandoval <osandov@fb.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com> Cc: Ewan D. Milne <emilne@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 05 Nov, 2020 1 commit
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Arnd Bergmann authored
There have been several attempts to fix serious problems in the compat handling in megasas_mgmt_compat_ioctl_fw(), and it also uses the compat_alloc_user_space() function. Folding the compat handling into the regular ioctl function with in_compat_syscall() simplifies it a lot and avoids some of the remaining problems: - missing handling of unaligned pointers - overflowing the ioc->frame.raw array from invalid input - compat_alloc_user_space() Link: https://lore.kernel.org/r/20201030164450.1253641-3-arnd@kernel.orgReviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 08 Jul, 2020 1 commit
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Damien Le Moal authored
Move function declarations to megaraid_sas.h to avoid warnings such as: warning: no previous prototype for ‘xxx' No functional changes. Link: https://lore.kernel.org/r/20200706123346.451827-1-damien.lemoal@wdc.comSigned-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 12 May, 2020 2 commits
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Chandrakanth Patil authored
Link: https://lore.kernel.org/r/20200508085314.23461-1-chandrakanth.patil@broadcom.comSigned-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
MFI_BIG_ENDIAN macro used in drivers structure bitfield to check the CPU big endianness is undefined which would break the code on big endian machine. __BIG_ENDIAN_BITFIELD kernel macro should be used in places of MFI_BIG_ENDIAN macro. Link: https://lore.kernel.org/r/20200508085130.23339-1-chandrakanth.patil@broadcom.com Fixes: a7faf81d ("scsi: megaraid_sas: Set no_write_same only for Virtual Disk") Cc: <stable@vger.kernel.org> # v5.6+ Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 16 Jan, 2020 3 commits
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Anand Lodnoor authored
Link: https://lore.kernel.org/r/1579000882-20246-12-git-send-email-anand.lodnoor@broadcom.comSigned-off-by: Anand Lodnoor <anand.lodnoor@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Anand Lodnoor authored
DCMD_INIT is introduced to indicate the initial DCMD status, which was earlier set to MFI status. DCMD_BUSY indicates the resource is busy or locked. Link: https://lore.kernel.org/r/1579000882-20246-8-git-send-email-anand.lodnoor@broadcom.comSigned-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Anand Lodnoor <anand.lodnoor@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Anand Lodnoor authored
Ideally, optimal queue depth will be provided by firmware. The driver defines will be used as a fallback mechanism in case the FW assisted QD is not supported. The driver defined values provide optimal queue depth for most of the drives and the workloads, as is learned from the firmware assisted QD results. Link: https://lore.kernel.org/r/1579000882-20246-4-git-send-email-anand.lodnoor@broadcom.comSigned-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Anand Lodnoor <anand.lodnoor@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 10 Oct, 2019 1 commit
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Chandrakanth Patil authored
Currently, MSI-X vectors name appears in /proc/interrupts is "megasas" which is same for all the vectors. This patch provides a unique name for all megaraid_sas controllers and their associated MSI-X interrupts. Link: https://lore.kernel.org/r/20191007051828.12294-1-chandrakanth.patil@broadcom.comSuggested-by: Konstantin Shalygin <k0ste@k0ste.ru> Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 13 Aug, 2019 1 commit
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Chandrakanth Patil authored
This patch provides a module parameter and sysfs interface to select whether the queue depth for each device should be based on the value suggested by firmware (the default) or the maximum supported by the controller (can_queue). Although we have a sysfs interface per sdev to change the queue depth of individual scsi devices, this implementation provides a single sysfs entry per shost to switch between the controller max and the value reported by firmware. The module parameter can provide an interface for one time grub settings and provides persistent settings across the boot. [mkp: tweaked commit desc] Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 12 Jul, 2019 1 commit
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Shivasharan S authored
Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 27 Jun, 2019 11 commits
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Chandrakanth Patil authored
Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
For Aero adapters, driver provides three different performance modes controlled through module parameter named 'perf_mode'. Below are those performance modes: 0: Balanced - Additional high IOPS reply queues will be enabled along with low latency queues. Interrupt coalescing will be enabled only for these high IOPS reply queues. 1: IOPS - No additional high IOPS queues are enabled. Interrupt coalescing will be enabled on all reply queues. 2: Latency - No additional high IOPS queues are enabled. Interrupt coalescing will be disabled on all reply queues. This is a legacy behavior similar to Ventura & Invader Series. Default performance mode settings: - Performance mode set to 'Balanced', if Aero controller is working in 16GT/s PCIe speed. - Performance mode will be set to 'Latency' mode for all other cases. Through module parameter 'perf_mode', user can override default performance mode to desired one. Captured some performance numbers with these performance modes. 4k Random Read IO performance numbers on 24 SAS SSD drives for above three performance modes. Performance data is from Intel Skylake and HGST SS300 (drive model SDLL1DLR400GCCA1). IOPS: ----------------------------------------------------------------------- |perf_mode | qd = 1 | qd = 64 | note | |-------------|--------|---------|------------------------------------- |balanced | 259K | 3061k | Provides max performance numbers | | | | | both on lower QD workload & | | | | | also on higher QD workload | |-------------|--------|---------|------------------------------------- |iops | 220K | 3100k | Provides max performance numbers | | | | | only on higher QD workload. | |-------------|--------|---------|------------------------------------- |latency | 246k | 2226k | Provides good performance numbers | | | | | only on lower QD worklaod. | ----------------------------------------------------------------------- Average Latency: ----------------------------------------------------- |perf_mode | qd = 1 | qd = 64 | |-------------|--------------|----------------------| |balanced | 92.05 usec | 501.12 usec | |-------------|--------------|----------------------| |iops | 108.40 usec | 498.10 usec | |-------------|--------------|----------------------| |latency | 97.10 usec | 689.26 usec | ----------------------------------------------------- Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
The driver will use round-robin method for IO submission in batches within the high IOPS queues when the number of in-flight ios on the target device is larger than 8. Otherwise the driver will use low latency reply queues. Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Driver should enable interrupt coalescing (during driver load and after Controller Reset) for High IOPS queues by masking appropriate bits in IOC INIT frame. Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Aero controllers support balanced performance mode through the ability to configure queues with different properties. Reply queues with interrupt coalescing enabled are called "high iops reply queues" and reply queues with interrupt coalescing disabled are called "low latency reply queues". The driver configures a combination of high iops and low latency reply queues if: - HBA is an AERO controller; - MSI-X vectors supported by the HBA is 128; - Total CPU count in the system more than high iops queue count; - Driver is loaded with default max_msix_vectors module parameter; and - System booted in non-kdump mode. Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Added driver support to allow passthrough MPI toolbox type MFI commands to firmware based on firmware capability. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Issue: This issue is applicable to scenario when JBOD sequence map is unavailable (memory allocation for JBOD sequence map failed) to driver but feature is supported by firmware. If the driver sends a JBOD IO by not adding 255 (MAX_PHYSICAL_DEVICES - 1) to device ID when underlying firmware supports JBOD sequence map, it will lead to the IO failure. Fix: For JBOD IOs, driver will not use the RAID map to fetch the devhandle if JBOD sequence map is unavailable. Driver will set Devhandle to 0xffff and Target ID to 'device ID + 255 (MAX_PHYSICAL_DEVICES - 1)'. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
On PowerPC architecture, calling disable_irq_nosync from IRQ context is not providing the required effect. In current megaraid_sas driver, disable_irq_nosync is being called from IRQ context before enabling IRQ poll. But due to the issue seen on PPC, after IRQ poll disable and legacy ISR is enabled, we are not seeing our ISR getting called. Fix: Call disable_irq from IRQ poll thread context instead of IRQ context. Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
This patch will add support for non-secure Aero adapter PCI IDs. Driver will throw an error message when a non-secure type controller is detected. Purpose of this interface is to avoid interacting with any firmware which is not secured/signed by Broadcom. Any tampering on Firmware component will be detected by hardware and it will be communicated to the driver to avoid any further interaction with that component. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Chandrakanth Patil authored
Aero adapters provides Atomic Request Descriptor as an alternative method for posting an entry onto a request queue. The posting of an Atomic Request Descriptor is an atomic operation, providing a safe mechanism for multiple processors on the host to post requests without synchronization. This Atomic Request Descriptor format is identical to first 32 bits of Default Request Descriptor and uses only 32 bits. If Aero adapters support Atomic descriptor, driver should use it for posting IOs and DCMDs to firmware. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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- 18 Jun, 2019 8 commits
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Shivasharan S authored
Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
Create a debugfs interface for megaraid_sas driver. Provide interface to dump driver RAID map in debugfs. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
Add debug prints related to device list being returned by firmware. The a debug flag to activate these prints. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
When driver detects a firmware fault during load, dump additional information on fault code and subcode that will help in debugging. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
This patch enhances the existing debug prints in reset and task management path. These debug prints in adapter reset path helps with debugging issues related to IO timeouts that are seen frequently in the field. Add additional debug prints to dump the pending command frames before initiating an adapter reset. Also, print FastPath IOs that are outstanding. Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
Driver will use "reply descriptor post queues" in round robin fashion when the combined MSI-X mode is not enabled. With this IO completions are distributed and load balanced across all the available reply descriptor post queues equally. This is enabled only if combined MSI-X mode is not enabled in firmware. This improves performance and also fixes soft lockups. When load balancing is enabled, IRQ affinity from driver needs to be disabled. Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
Issue Description: We have seen cpu lock up issues from field if system has a large (more than 96) logical cpu count. SAS3.0 controller (Invader series) supports max 96 MSI-X vector and SAS3.5 product (Ventura) supports max 128 MSI-X vectors. This may be a generic issue (if PCI device support completion on multiple reply queues). Let me explain it w.r.t megaraid_sas supported h/w just to simplify the problem and possible changes to handle such issues. MegaRAID controller supports multiple reply queues in completion path. Driver creates MSI-X vectors for controller as "minimum of (FW supported Reply queues, Logical CPUs)". If submitter is not interrupted via completion on same CPU, there is a loop in the IO path. This behavior can cause hard/soft CPU lockups, IO timeout, system sluggish etc. Example - one CPU (e.g. CPU A) is busy submitting the IOs and another CPU (e.g. CPU B) is busy with processing the corresponding IO's reply descriptors from reply descriptor queue upon receiving the interrupts from HBA. If CPU A is continuously pumping the IOs then always CPU B (which is executing the ISR) will see the valid reply descriptors in the reply descriptor queue and it will be continuously processing those reply descriptor in a loop without quitting the ISR handler. megaraid_sas driver will exit ISR handler if it finds unused reply descriptor in the reply descriptor queue. Since CPU A will be continuously sending the IOs, CPU B may always see a valid reply descriptor (posted by HBA Firmware after processing the IO) in the reply descriptor queue. In worst case, driver will not quit from this loop in the ISR handler. Eventually, CPU lockup will be detected by watchdog. Above mentioned behavior is not common if "rq_affinity" set to 2 or affinity_hint is honored by irqbalancer as "exact". If rq_affinity is set to 2, submitter will be always interrupted via completion on same CPU. If irqbalancer is using "exact" policy, interrupt will be delivered to submitter CPU. Problem statement: If CPU count to MSI-X vectors (reply descriptor Queues) count ratio is not 1:1, we still have exposure of issue explained above and for that we don't have any solution. Exposure of soft/hard lockup is seen if CPU count is more than MSI-X supported by device. If CPUs count to MSI-X vectors count ratio is not 1:1, (Other way, if CPU counts to MSI-X vector count ratio is something like X:1, where X > 1) then 'exact' irqbalance policy OR rq_affinity = 2 won't help to avoid CPU hard/soft lockups. There won't be any one to one mapping between CPU to MSI-X vector instead one MSI-X interrupt (or reply descriptor queue) is shared with group/set of CPUs and there is a possibility of having a loop in the IO path within that CPU group and may observe lockups. For example: Consider a system having two NUMA nodes and each node having four logical CPUs and also consider that number of MSI-X vectors enabled on the HBA is two, then CPUs count to MSI-X vector count ratio as 4:1. e.g. MSI-X vector 0 is affinity to CPU 0, CPU 1, CPU 2 & CPU 3 of NUMA node 0 and MSI-X vector 1 is affinity to CPU 4, CPU 5, CPU 6 & CPU 7 of NUMA node 1. numactl --hardware available: 2 nodes (0-1) node 0 cpus: 0 1 2 3 --> MSI-X 0 node 0 size: 65536 MB node 0 free: 63176 MB node 1 cpus: 4 5 6 7 --> MSI-X 1 node 1 size: 65536 MB node 1 free: 63176 MB Assume that user started an application which uses all the CPUs of NUMA node 0 for issuing the IOs. Only one CPU from affinity list (it can be any cpu since this behavior depends upon irqbalance) CPU0 will receive the interrupts from MSI-X 0 for all the IOs. Eventually, CPU 0 IO submission percentage will be decreasing and ISR processing percentage will be increasing as it is more busy with processing the interrupts. Gradually IO submission percentage on CPU 0 will be zero and it's ISR processing percentage will be 100% as IO loop has already formed within the NUMA node 0, i.e. CPU 1, CPU 2 & CPU 3 will be continuously busy with submitting the heavy IOs and only CPU 0 is busy in the ISR path as it always find the valid reply descriptor in the reply descriptor queue. Eventually, we will observe the hard lockup here. Chances of occurring of hard/soft lockups are directly proportional to value of X. If value of X is high, then chances of observing CPU lockups is high. Solution: Use IRQ poll interface defined in "irq_poll.c". megaraid_sas driver will execute ISR routine in softirq context and it will always quit the loop based on budget provided in IRQ poll interface. Driver will switch to IRQ poll only when more than a threshold number of reply descriptors are handled in one ISR. Currently threshold is set as 1/4th of HBA queue depth. In these scenarios (i.e. where CPUs count to MSI-X vectors count ratio is X:1 (where X > 1)), IRQ poll interface will avoid CPU hard lockups due to voluntary exit from the reply queue processing based on budget. Note - Only one MSI-X vector is busy doing processing. Select CONFIG_IRQ_POLL from driver Kconfig for driver compilation. Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Shivasharan S authored
While an online controller reset(OCR) is in progress, there is short duration where all access to controller's PCI config space from the host needs to be blocked. This is due to a hardware limitation of MegaRAID controllers. With this patch, driver will block all access to controller's config space from userland applications by calling pci_cfg_access_lock() while OCR is in progress and unlocking after controller comes back to ready state. Added helper function which locks the config space before initiating OCR and wait for controller to become READY. Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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