kernel.git/drivers/scsi/cxlflash, branch linux-4.6.y

Merge branch 'fixes-base' into fixes

2016-04-05T10:56:47Z

cxlflash: Move to exponential back-off when cmd_room is not available

2016-03-29T00:43:34Z

While profiling the cxlflash_queuecommand() path under a heavy load it was found that number of retries to find cmd_room was fairly high. There are two problems with the current back-off: a) It starts with a udelay of 0 b) It backs-off linearly Tried several approaches (a higher multiple 10*n, 100*n, as well as n^2, 2^n) and found that the exponential back-off(2^n) approach had the least overall cost. Cost as being defined as overall time spent waiting. The fix is to change the linear back-off to an exponential back-off. This solution also takes care of the problem with the initial delay (starts with 1 usec). Signed-off-by: Manoj N. Kumar Acked-by: Matthew R. Ochs Reviewed-by: Johannes Thumshirn Signed-off-by: Uma Krishnan Signed-off-by: Martin K. Petersen

cxlflash: Fix regression issue with re-ordering patch

2016-03-29T00:43:17Z

While running 'sg_reset -H' back to back the following exception was seen: [ 735.115695] Faulting instruction address: 0xd0000000098c0864 cpu 0x0: Vector: 300 (Data Access) at [c000000ffffafa80] pc: d0000000098c0864: cxlflash_async_err_irq+0x84/0x5c0 [cxlflash] lr: c00000000013aed0: handle_irq_event_percpu+0xa0/0x310 sp: c000000ffffafd00 msr: 9000000000009033 dar: 2010000 dsisr: 40000000 current = 0xc000000001510880 paca = 0xc00000000fb80000 softe: 0 irq_happened: 0x01 pid = 0, comm = swapper/0 Linux version 4.5.0-491-26f710d+ enter ? for help [c000000ffffafe10] c00000000013aed0 handle_irq_event_percpu+0xa0/0x310 [c000000ffffafed0] c00000000013b1a8 handle_irq_event+0x68/0xc0 [c000000ffffaff00] c0000000001404ec handle_fasteoi_irq+0xec/0x2a0 [c000000ffffaff30] c00000000013a084 generic_handle_irq+0x54/0x80 [c000000ffffaff60] c000000000011130 __do_irq+0x80/0x1d0 [c000000ffffaff90] c000000000024d40 call_do_irq+0x14/0x24 [c000000001573a20] c000000000011318 do_IRQ+0x98/0x140 [c000000001573a70] c000000000002594 hardware_interrupt_common+0x114/0x180 This exception is being hit because the async_err interrupt path performs an MMIO to read the interrupt status register. The MMIO region in this case is not available. Commit 6ded8b3cbd9a ("cxlflash: Unmap problem state area before detaching master context") re-ordered the sequence in which term_mc() and stop_afu() are called. This introduces a window for interrupts to come in with the problem space area unmapped, that did not exist previously. The fix is to separate the disabling of all AFU interrupts to a distinct function, term_intr() so that it is the first thing that is done in the tear down process. To keep the initialization process symmetric, separate the AFU interrupt setup also to a distinct function: init_intr(). Fixes: 6ded8b3cbd9a ("cxlflash: Unmap problem state area before detaching master context") Signed-off-by: Manoj N. Kumar Acked-by: Matthew R. Ochs Reviewed-by: Johannes Thumshirn Signed-off-by: Uma Krishnan Signed-off-by: Martin K. Petersen

Merge tag 'powerpc-4.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2016-03-19T22:38:41Z

Pull powerpc updates from Michael Ellerman: "This was delayed a day or two by some build-breakage on old toolchains which we've now fixed. There's two PCI commits both acked by Bjorn. There's one commit to mm/hugepage.c which is (co)authored by Kirill. Highlights: - Restructure Linux PTE on Book3S/64 to Radix format from Paul Mackerras - Book3s 64 MMU cleanup in preparation for Radix MMU from Aneesh Kumar K.V - Add POWER9 cputable entry from Michael Neuling - FPU/Altivec/VSX save/restore optimisations from Cyril Bur - Add support for new ftrace ABI on ppc64le from Torsten Duwe Various cleanups & minor fixes from: - Adam Buchbinder, Andrew Donnellan, Balbir Singh, Christophe Leroy, Cyril Bur, Luis Henriques, Madhavan Srinivasan, Pan Xinhui, Russell Currey, Sukadev Bhattiprolu, Suraj Jitindar Singh. General: - atomics: Allow architectures to define their own __atomic_op_* helpers from Boqun Feng - Implement atomic{, 64}_*_return_* variants and acquire/release/ relaxed variants for (cmp)xchg from Boqun Feng - Add powernv_defconfig from Jeremy Kerr - Fix BUG_ON() reporting in real mode from Balbir Singh - Add xmon command to dump OPAL msglog from Andrew Donnellan - Add xmon command to dump process/task similar to ps(1) from Douglas Miller - Clean up memory hotplug failure paths from David Gibson pci/eeh: - Redesign SR-IOV on PowerNV to give absolute isolation between VFs from Wei Yang. - EEH Support for SRIOV VFs from Wei Yang and Gavin Shan. - PCI/IOV: Rename and export virtfn_{add, remove} from Wei Yang - PCI: Add pcibios_bus_add_device() weak function from Wei Yang - MAINTAINERS: Update EEH details and maintainership from Russell Currey cxl: - Support added to the CXL driver for running on both bare-metal and hypervisor systems, from Christophe Lombard and Frederic Barrat. - Ignore probes for virtual afu pci devices from Vaibhav Jain perf: - Export Power8 generic and cache events to sysfs from Sukadev Bhattiprolu - hv-24x7: Fix usage with chip events, display change in counter values, display domain indices in sysfs, eliminate domain suffix in event names, from Sukadev Bhattiprolu Freescale: - Updates from Scott: "Highlights include 8xx optimizations, 32-bit checksum optimizations, 86xx consolidation, e5500/e6500 cpu hotplug, more fman and other dt bits, and minor fixes/cleanup" * tag 'powerpc-4.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (179 commits) powerpc: Fix unrecoverable SLB miss during restore_math() powerpc/8xx: Fix do_mtspr_cpu6() build on older compilers powerpc/rcpm: Fix build break when SMP=n powerpc/book3e-64: Use hardcoded mttmr opcode powerpc/fsl/dts: Add "jedec,spi-nor" flash compatible powerpc/T104xRDB: add tdm riser card node to device tree powerpc32: PAGE_EXEC required for inittext powerpc/mpc85xx: Add pcsphy nodes to FManV3 device tree powerpc/mpc85xx: Add MDIO bus muxing support to the board device tree(s) powerpc/86xx: Introduce and use common dtsi powerpc/86xx: Update device tree powerpc/86xx: Move dts files to fsl directory powerpc/86xx: Switch to kconfig fragments approach powerpc/86xx: Update defconfigs powerpc/86xx: Consolidate common platform code powerpc32: Remove one insn in mulhdu powerpc32: small optimisation in flush_icache_range() powerpc: Simplify test in __dma_sync() powerpc32: move xxxxx_dcache_range() functions inline powerpc32: Remove clear_pages() and define clear_page() inline ...

cxlflash: Use new cxl_pci_read_adapter_vpd() API

2016-03-09T12:40:01Z

To read the adapter VPD, drivers can't rely on pci config APIs, as it wouldn't work on powerVM. cxl introduced a new kernel API especially for this, so start using it. Co-authored-by: Christophe Lombard Signed-off-by: Frederic Barrat Signed-off-by: Christophe Lombard Reviewed-by: Uma Krishnan Acked-by: Matthew R. Ochs Acked-by: Manoj N. Kumar Signed-off-by: Michael Ellerman

cxlflash: Increase cmd_per_lun for better throughput

2016-03-09T02:17:33Z

With the current value of cmd_per_lun at 16, the throughput over a single adapter is limited to around 150kIOPS. Increase the value of cmd_per_lun to 256 to improve throughput. With this change a single adapter is able to attain close to the maximum throughput (380kIOPS). Also change the number of RRQ entries that can be queued. Signed-off-by: Manoj N. Kumar Acked-by: Matthew R. Ochs Reviewed-by: Uma Krishnan Signed-off-by: Martin K. Petersen

cxlflash: Fix to avoid unnecessary scan with internal LUNs

2016-03-09T02:17:33Z

When switching to the internal LUN defined on the IBM CXL flash adapter, there is an unnecessary scan occurring on the second port. This scan leads to the following extra lines in the log: Dec 17 10:09:00 tul83p1 kernel: [ 3708.561134] cxlflash 0008:00:00.0: cxlflash_queuecommand: (scp=c0000000fc1f0f00) 11/1/0/0 cdb=(A0000000-00000000-10000000-00000000) Dec 17 10:09:00 tul83p1 kernel: [ 3708.561147] process_cmd_err: cmd failed afu_rc=32 scsi_rc=0 fc_rc=0 afu_extra=0xE, scsi_extra=0x0, fc_extra=0x0 By definition, both of the internal LUNs are on the first port/channel. When the lun_mode is switched to internal LUN the same value for host->max_channel is retained. This causes an unnecessary scan over the second port/channel. This fix alters the host->max_channel to 0 (1 port), if internal LUNs are configured and switches it back to 1 (2 ports) while going back to external LUNs. Signed-off-by: Manoj N. Kumar Acked-by: Matthew R. Ochs Reviewed-by: Uma Krishnan Signed-off-by: Martin K. Petersen

cxlflash: Reorder user context initialization

2016-03-09T02:17:33Z

In order to support cxlflash in the PowerVM environment, underlying hypervisor APIs have imposed a kernel API ordering change. For the superpipe access to LUN, user applications need a context. The cxlflash module creates this context by making a sequence of cxl calls. In the current code, a context is initialized via cxl_dev_context_init() followed by cxl_process_element(), a function that obtains the process element id. Finally, cxl_start_work() is called to attach the process element. In the PowerVM environment, a process element id cannot be obtained from the hypervisor until the process element is attached. The cxlflash module is unable to create contexts without a valid process element id. To fix this problem, cxl_start_work() is called before obtaining the process element id. Signed-off-by: Uma Krishnan Acked-by: Matthew R. Ochs Signed-off-by: Martin K. Petersen

cxlflash: Simplify attach path error cleanup

2016-03-09T02:17:33Z

The cxlflash_disk_attach() routine currently uses a cascading error gate strategy for its error cleanup path. While this strategy is commonly used to handle cleanup scenarios, it is too restrictive when function callouts need to be restructured. Problems range from inserting error path bugs in previously 'good' code to the cleanup path imposing design changes to how the normal path is structured. A less restrictive approach is needed to support ordering changes that come about when operating in different environments. To overcome this restriction, the error cleanup path is modified to have a single entrypoint and use conditional logic to cleanup where necessary. Entities that require multiple cleanup steps must be carefully vetted to ensure their APIs support state. In cases where they do not (none as of this commit) additional local variables can be used to maintain state on their behalf. Signed-off-by: Matthew R. Ochs Reviewed-by: Uma Krishnan Signed-off-by: Martin K. Petersen

cxlflash: Split out context initialization

2016-03-09T02:17:33Z

Presently, context information structures are allocated and initialized in the same routine, create_context(). This imposes an ordering restriction such that all pieces of information needed to initialize a context must be known before the context is even allocated. This design point is not flexible when the order of context creation needs to be modified. Specifically, this can lead to problems when members of the context information structure are a part of an ordering dependency (i.e. - the 'work' structure embedded within the context). To remedy, the allocation is left as-is, inside of the existing create_context() routine and the initialization is transitioned to a new void routine, init_context(). At the same time, in anticipation of these routines not being called in sequence, a state boolean is added to the context information structure to track when the context has been initilized. The context teardown routine, destroy_context(), is modified to support being called with a non-initialized context. Signed-off-by: Matthew R. Ochs Reviewed-by: Uma Krishnan Signed-off-by: Martin K. Petersen