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2011-07-22tcm_fc: Makefile cleanupsNicholas Bellinger1-13/+4
This patch removes the unnecessary EXTRA_CFLAGS includes, and drops the unused -DTCM_FC_DEBUG define. Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22loopback: Fix memory leak in tcm_loop_make_scsi_hba()Jesper Juhl1-9/+8
There is a memory leak in tcm_loop_make_scsi_hba(). If all the strstr() calls return NULL and we end up at return ERR_PTR(-EINVAL); then we'll be leaking the memory previously allocated to tl_hba as that variable goes out of scope. This patch should fix the leak. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22loopback: Remove duplicate scsi/scsi_tcq.h includeJesper Juhl1-1/+0
Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22loopback: off by one in tcm_loop_make_naa_tpg()Dan Carpenter1-1/+1
This is an off by one 'tgpt' check in tcm_loop_make_naa_tpg() that could result in memory corruption. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target/iblock: Remove unused iblock_dev membersRoland Dreier2-19/+3
ibd_depth and ibd_force are used write-only. Remove them. ibd_major/minor can be easily retrieved from ibd_bd, so get rid of them too. Signed-off-by: Roland Dreier <roland@purestorage.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target/iblock: Use request_queue->nr_request for se_device defaultsNicholas Bellinger2-4/+2
This patch converts iblock_create_virtdevice() to use request_queue->nr_request for se_dev_limits usage of ->hw_queue_depth and ->queue_depth for individual struct se_device export. It also removes the now unused defines for IBLOCK_DEVICE_QUEUE_DEPTH and IBLOCK_MAX_DEVICE_QUEUE_DEPTH Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Make se_tmr_lock IRQ-safeRoland Dreier2-12/+13
transport_lookup_tmr_lun() can be called from interrupt context and therefore needs to use IRQ-safe spinlock functions. Fix this up, and to make the locking work, convert the other uses of se_tmr_lock to be IRQ-disabling. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Make se_dev_check_online() locking IRQ-safeRoland Dreier1-2/+3
se_dev_check_online() is called from transport_lookup_cmd_lun(), which as discussed before may be called from interrupt context. So it needs to use spin_lock_irqsave() instead of spin_lock_irq() to avoid enabling interrupts at the wrong time. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Make transport_lookup_cmd_lun() locking IRQ-safeRoland Dreier1-5/+5
transport_lookup_cmd_lun() may be called from interrupt context (eg tcm_loop_allocate_core_cmd() calls it, and it has a comment that says, "Can be called from interrupt context"), so it needs to use spin_lock_irqsave() instead of spin_lock_irq() to avoid enabling interrupts at the wrong time. (And indeed the last set of lock operations, on lun_cmd_lock, were already using spin_lock_irqsave(), so we just need to fix the other two locks we take) Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Add SCF_EMULATE_QUEUE_FULL -> transport_handle_queue_fullNicholas Bellinger2-15/+188
This patch adds SCF_EMULATE_QUEUE_FULL support using -EAGAIN failures via transport_handle_queue_full() to signal queue full in completion path TFO->queue_data_in() and TFO->queue_status() callbacks. This is done using a new se_cmd->transport_qf_callback() to handle the following queue full exception cases within target core: *) TRANSPORT_COMPLETE_OK (for completion path queue full) *) TRANSPORT_COMPLETE_QF_WP (for TRANSPORT_WRITE_PENDING queue full) *) transport_send_check_condition_and_sense() failure paths in transport_generic_request_failure() and transport_generic_complete_ok() All logic is driven using se_device->qf_work_queue -> target_qf_do_work() to to requeue outstanding se_cmd at the head of se_dev->queue_obj->qobj_list for transport_processing_thread() execution. Tested using tcm_qla2xxx with MAX_OUTSTANDING_COMMANDS=128 for FCP READ to trigger the TRANSPORT_COMPLETE_OK queue full cases, and a simulated TFO->write_pending() -EAGAIN failure to trigger TRANSPORT_COMPLETE_QF_WP. Reported-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Add transport_handle_cdb_direct optimizationNicholas Bellinger2-0/+25
This patch adds a transport_handle_cdb_direct() optimization for mapping and queueing tasks directly from within fabric processing context by calling the newly exported transport_generic_new_cmd(). This currently expects to be called from process context only, and will fail if called within interrupt context. This patch also leaves transport_generic_handle_cdb() unmodified for the moment to function as expected with existing tcm_fc and ib_srpt fabrics, and will be removed once these have been converted and tested with v4.1 code using transport_handle_cdb_direct(). Based on Andy's original patch here: [PATCH 39/42] target: Call transport_new_cmd instead of adding to cmd queue Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: merge release_cmd methodsChristoph Hellwig7-60/+35
The release_cmd_to_pool and release_cmd_direct methods are always the same. Merge them into a single release_cmd method, and clean up the fallout. (nab: fix breakage in transport_generic_free_cmd() parameter build breakage in drivers/target/tcm_fc/tfc_cmd.c) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: remove the unused SCF_* flagsChristoph Hellwig2-29/+5
This patch contains a squashed version to remove unused SCF_* flags: target: remove the unused SCF_SE_DISABLE_ONLINE_CHECK flag target: remove the unused SCF_CMD_PASSTHROUGH_NOALLOC flag target: remove the unused SCF_EMULATE_SYNC_UNMAP flag target: remove the unused SCF_EMULATE_SYNC_CACHE flag Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: remove the always-noop ->new_cmd_failure methodChristoph Hellwig8-31/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Updates from AGrover and HCH (round 3)Andy Grover17-753/+583
This patch contains a squashed version of third round series cleanups, improvements ,and simplfications from Andy and Christoph ahead of the heavy lifting between round 3 -> 4 for the target core SGL conversion. This include cleanups to the main target I/O path and other miscellaneous updates. target: Replace custom sg<->buf functions with lib funcs target: Simplify sector limiting code target: get_cdb should never return NULL target: Simplify transport_memcpy_se_mem_read_contig target: Use assignment rather than increment for t_task_cdbs target: Don't pass dma_size to generic_get_mem target: Pass sg with type scatterlist in transport_map_sg_to_mem target: Move task_sg_num next to task_sg in struct se_task target: inline struct se_transport_task into struct se_cmd target: Change name & semantics of transport_get_sectors() target: Remove unused members of se_cmd target: Rename se_cmd.t_task_cdbs to t_task_list_num target: Fix some spelling target: Remove unused var from transport_generic_do_tmr target: map_sg_to_mem: return sg_count in return value target/pscsi: Use min_t for sector limits target/pscsi: Unused param for pscsi_get_bio() target: Rename get_cdb_count to allocate_tasks target: Make transport_generic_new_cmd() available for iscsi-target target: Remove fabric callback to allocate iovecs target: Fix transport_generic_new_cmd WRITE comment (hch: Use __GFP_ZERO usage for alloc_pages() usage) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Fix WRITE_SAME_[16,32] number of blocks=0 caseNicholas Bellinger2-10/+32
This patch fixes the handling of WRITE_SAME_[16,32] emulation where a WRITE_SAME_* CDB with number of blocks=0 was being rejected by SCSI expected data transfer length overflow checking in target core. It changes both CDB cases in transport_generic_cmd_sequencer() to use dev->se_sub_dev->se_dev_attrib.block_size to match what sg_write_same is sending us with --num=0. It also fixes target_emulate_write_same() to properly determine the num_blocks with --num=0 case to determine the remaining range for dev->transport->do_discard(). Reported-by: Chris Greiveldinger <chris.greiveldinger@rnanetworks.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: Fix WRITE_SAME_16 t_task_lba assignment bugNicholas Bellinger1-1/+1
This patch fixes a bug in the assignment of cmd->t_task.t_task_lba with WRITE_SAME_16 to correctly use get_unaligned_be64() for the 64-bit LBA. Reported-by: Chris Greiveldinger <chris.greiveldinger@rnanetworks.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: More core cleanups from AGrover (round 2)Andy Grover19-941/+761
This patch contains the squashed version of second round of target core cleanups and simplifications and Andy and Co. It also contains a handful of fixes to address bugs the original series and other minor cleanups. Here is the condensed shortlog: target: Remove unneeded casts to void* target: Rename get_lun_for_{cmd,tmr} to lookup_{cmd,tmr}_lun target: Make t_task a member of se_cmd, not a pointer target: Handle functions returning "-2" target: Use cmd->se_dev over cmd->se_lun->lun_se_dev target: Embed qr in struct se_cmd target: Replace embedded struct se_queue_req with a list_head target: Rename list_heads that are nodes in struct se_cmd to "*_node" target: Fold transport_device_setup_cmd() into lookup_{tmr,cmd}_lun() target: Make t_mem_list and t_mem_list_bidi members of t_task target: Add comment & cleanup transport_map_sg_to_mem() target: Remove unneeded checks in transport_free_pages() (Roland: Fix se_queue_req removal leftovers OOPs) (nab: Fix transport_lookup_tmr_lun failure case) (nab: Fix list_empty(&cmd->t_task.t_mem_bidi_list) inversion bugs) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Fix double test of inquiry_prodRoland Dreier1-1/+1
The code in transport_add_device_to_core_hba() really intends to make sure that neither inquiry_prod nor inquiry_rev is NULL. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: Core cleanups from AGrover (round 1)Andy Grover27-1940/+1703
This patch contains the squashed version of a number of cleanups and minor fixes from Andy's initial series (round 1) for target core this past spring. The condensed log looks like: target: use errno values instead of returning -1 for everything target: Rename transport_calc_sg_num to transport_init_task_sg target: Fix leak in error path in transport_init_task_sg target/pscsi: Remove pscsi_get_sh() usage target: Make two runtime checks into WARN_ONs target: Remove hba queue depth and convert to spin_lock_irq usage target: dev->dev_status_queue_obj is unused target: Make struct se_queue_req.cmd type struct se_cmd * target: Remove __transport_get_qr_from_queue() target: Rename se_dev->g_se_dev_list to se_dev_node target: Remove struct se_global target: Simplify scsi mib index table code target: Make dev_queue_obj a member of se_device instead of a pointer target: remove extraneous returns at end of void functions target: Ensure transport_dump_vpd_ident_type returns null-terminated str target: Function pointers don't need to use '&' to be assigned target: Fix comment in __transport_execute_tasks() target: Misc style cleanups target: rename struct pr_reservation_template to pr_reservation target: Remove #defines that just perform indirection target: Inline transport_get_task_from_execute_queue() target: Minor header comment fixes Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-07-22target: Remove unused su_group usage in fabric register/dergisterNicholas Bellinger1-15/+0
This patch removes two instances of left over v3.x code performing local scope access to struct target_core_fabric_ops->tf_subsys->su_group in target_fabric_configfs_register() and target_fabric_configfs_deregister(). Reported-by: Christophe Fergeau <cfergeau@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: Remove unnecessary *cdb transport_get_lun_for_cmd parameterNicholas Bellinger4-4/+3
This patch removes the now unnecessary 'unsigned char *cdb' function parameter from transport_get_lun_for_cmd(). This also includes updating lio-target, tcm_loop and tcm_fc usage of transport_get_lun_for_cmd(). Reported-by: Fubo Chen <fubo.chen@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: use MAINTENANCE_IN and MAINTENANCE_OUT definitions in scsi.hNicholas Bellinger1-2/+2
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22target: Check LUN numbers in transport_get_lun_for_[cmd,tmr]Fubo Chen1-0/+12
This patch checks the passed 'unpacked_lun' against TRANSPORT_MAX_LUNS_PER_TPG before reading from struct se_node_acl->device_list[]. Signed-off-by: Fubo Chen <fubo.chen@gmail.com> Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-22Linux 3.0v3.0Linus Torvalds1-1/+1
2011-07-22Merge branch 'for_linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: sparc,kgdbts: fix compile regression with kgdb test suite
2011-07-22sparc,kgdbts: fix compile regression with kgdb test suiteJason Wessel1-0/+1
Commit 63ab25ebbc (kgdbts: unify/generalize gdb breakpoint adjustment) introduced a compile regression on sparc. kgdbts.c: In function 'check_and_rewind_pc': kgdbts.c:307: error: implicit declaration of function 'instruction_pointer_set' Simply add the correct macro definition for instruction pointer on the Sparc architecture. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Acked-by: David S. Miller <davem@davemloft.net>
2011-07-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6Linus Torvalds1-1/+1
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: CIFS: Fix wrong length in cifs_iovec_read
2011-07-21Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds1-0/+16
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Make Dell Latitude E6420 use reboot=pci x86: Make Dell Latitude E5420 use reboot=pci
2011-07-21x86: Make Dell Latitude E6420 use reboot=pciH. Peter Anvin1-0/+8
Yet another variant of the Dell Latitude series which requires reboot=pci. From the E5420 bug report by Daniel J Blueman: > The E6420 is affected also (same platform, different casing and > features), which provides an external confirmation of the issue; I can > submit a patch for that later or include it if you prefer: > http://linux.koolsolutions.com/2009/08/04/howto-fix-linux-hangfreeze-during-reboots-and-restarts/ Reported-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@kernel.org>
2011-07-21x86: Make Dell Latitude E5420 use reboot=pciDaniel J Blueman1-0/+8
Rebooting on the Dell E5420 often hangs with the keyboard or ACPI methods, but is reliable via the PCI method. [ hpa: this was deferred because we believed for a long time that the recent reshuffling of the boot priorities in commit 660e34cebf0a11d54f2d5dd8838607452355f321 fixed this platform. Unfortunately that turned out to be incorrect. ] Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Link: http://lkml.kernel.org/r/1305248699-2347-1-git-send-email-daniel.blueman@gmail.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@kernel.org>
2011-07-21Merge branch 'drm-intel-fixes' of ↵Linus Torvalds4-39/+56
git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6 * 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6: drm/i915: Fix unfenced alignment on pre-G33 hardware drm/i915: Add quirk to disable SSC on Lenovo U160 LVDS
2011-07-21vfs: drop conditional inode prefetch in __do_lookup_rcuLinus Torvalds1-2/+0
It seems to hurt performance in real life. Yes, the inode will be used later, but the conditional doesn't seem to predict all that well (negative dentries are not uncommon) and it looks like the cost of prefetching is simply higher than depending on the cache doing the right thing. As usual. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-21FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loopJan Beulich1-9/+5
The compiler, at least for ix86 and m68k, validly warns that the comparison: next <= (loff_t)-1 is always true (and it's always true also for x86-64 and probably all other arches - as long as pgoff_t isn't wider than loff_t). The intention appears to be to avoid wrapping of "next", so rather than eliminating the pointless comparison, fix the loop to indeed get exited when "next" would otherwise wrap. On m68k the following warning is observed: fs/fscache/page.c: In function '__fscache_uncache_all_inode_pages': fs/fscache/page.c:979: warning: comparison is always false due to limited range of data type Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Reported-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Suresh Jayaraman <sjayaraman@suse.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-21CIFS: Fix wrong length in cifs_iovec_readPavel Shilovsky1-1/+1
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-07-21Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds5-28/+103
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: signal: align __lock_task_sighand() irq disabling and RCU softirq,rcu: Inform RCU of irq_exit() activity sched: Add irq_{enter,exit}() to scheduler_ipi() rcu: protect __rcu_read_unlock() against scheduler-using irq handlers rcu: Streamline code produced by __rcu_read_unlock() rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special rcu: decrease rcu_report_exp_rnp coupling with scheduler
2011-07-21Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds4-61/+190
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Avoid creating superfluous NUMA domains on non-NUMA systems sched: Allow for overlapping sched_domain spans sched: Break out cpu_power from the sched_group structure
2011-07-21Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds3-2/+10
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86. reboot: Make Dell Latitude E6320 use reboot=pci x86, doc only: Correct real-mode kernel header offset for init_size x86: Disable AMD_NUMA for 32bit for now
2011-07-20Merge branch 'rcu/urgent' of ↵Ingo Molnar5-28/+103
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent
2011-07-20signal: align __lock_task_sighand() irq disabling and RCUPaul E. McKenney1-6/+13
The __lock_task_sighand() function calls rcu_read_lock() with interrupts and preemption enabled, but later calls rcu_read_unlock() with interrupts disabled. It is therefore possible that this RCU read-side critical section will be preempted and later RCU priority boosted, which means that rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but with interrupts disabled. This results in lockdep splats, so this commit nests the RCU read-side critical section within the interrupt-disabled region of code. This prevents the RCU read-side critical section from being preempted, and thus prevents the attempt to deboost with interrupts disabled. It is quite possible that a better long-term fix is to make rt_mutex_unlock() disable irqs when acquiring the rt_mutex structure's ->wait_lock. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20softirq,rcu: Inform RCU of irq_exit() activityPeter Zijlstra2-3/+11
The rcu_read_unlock_special() function relies on in_irq() to exclude scheduler activity from interrupt level. This fails because exit_irq() can invoke the scheduler after clearing the preempt_count() bits that in_irq() uses to determine that it is at interrupt level. This situation can result in failures as follows: $task IRQ SoftIRQ rcu_read_lock() /* do stuff */ <preempt> |= UNLOCK_BLOCKED rcu_read_unlock() --t->rcu_read_lock_nesting irq_enter(); /* do stuff, don't use RCU */ irq_exit(); sub_preempt_count(IRQ_EXIT_OFFSET); invoke_softirq() ttwu(); spin_lock_irq(&pi->lock) rcu_read_lock(); /* do stuff */ rcu_read_unlock(); rcu_read_unlock_special() rcu_report_exp_rnp() ttwu() spin_lock_irq(&pi->lock) /* deadlock */ rcu_read_unlock_special(t); Ed can simply trigger this 'easy' because invoke_softirq() immediately does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff first, but even without that the above happens. Cure this by also excluding softirqs from the rcu_read_unlock_special() handler and ensuring the force_irqthreads ksoftirqd/# wakeup is done from full softirq context. [ Alternatively, delaying the ->rcu_read_lock_nesting decrement until after the special handling would make the thing more robust in the face of interrupts as well. And there is a separate patch for that. ] Cc: Thomas Gleixner <tglx@linutronix.de> Reported-and-tested-by: Ed Tomlinson <edt@aei.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20sched: Add irq_{enter,exit}() to scheduler_ipi()Peter Zijlstra1-6/+38
Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual work. Traditionally we never did any actual work from the resched IPI and all magic happened in the return from interrupt path. Now that we do do some work, we need to ensure irq_{enter,exit} are called so that we don't confuse things. This affects things like timekeeping, NO_HZ and RCU, basically everything with a hook in irq_enter/exit. Explicit examples of things going wrong are: sched_clock_cpu() -- has a callback when leaving NO_HZ state to take a new reading from GTOD and TSC. Without this callback, time is stuck in the past. RCU -- needs in_irq() to work in order to avoid some nasty deadlocks Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20rcu: protect __rcu_read_unlock() against scheduler-using irq handlersPaul E. McKenney1-5/+24
The addition of RCU read-side critical sections within runqueue and priority-inheritance lock critical sections introduced some deadlock cycles, for example, involving interrupts from __rcu_read_unlock() where the interrupt handlers call wake_up(). This situation can cause the instance of __rcu_read_unlock() invoked from interrupt to do some of the processing that would otherwise have been carried out by the task-level instance of __rcu_read_unlock(). When the interrupt-level instance of __rcu_read_unlock() is called with a scheduler lock held from interrupt-entry/exit situations where in_irq() returns false, deadlock can result. This commit resolves these deadlocks by using negative values of the per-task ->rcu_read_lock_nesting counter to indicate that an instance of __rcu_read_unlock() is in flight, which in turn prevents instances from interrupt handlers from doing any special processing. This patch is inspired by Steven Rostedt's earlier patch that similarly made __rcu_read_unlock() guard against interrupt-mediated recursion (see https://lkml.org/lkml/2011/7/15/326), but this commit refines Steven's approach to avoid the need for preemption disabling on the __rcu_read_unlock() fastpath and to also avoid the need for manipulating a separate per-CPU variable. This patch avoids need for preempt_disable() by instead using negative values of the per-task ->rcu_read_lock_nesting counter. Note that nested rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will never see ->rcu_read_lock_nesting go to zero, and will therefore never invoke rcu_read_unlock_special(), thus preventing them from seeing the RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special. This patch also adds a check for ->rcu_read_unlock_special being negative in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS bit from being set should a scheduling-clock interrupt occur while __rcu_read_unlock() is exiting from an outermost RCU read-side critical section. Of course, __rcu_read_unlock() can be preempted during the time that ->rcu_read_lock_nesting is negative. This could result in the setting of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it, and would also result it this task being queued on the corresponding rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side critical section would enter rcu_read_unlock_special() to clean up -- which could result in deadlock if that critical section happened to be in the scheduler where the runqueue or priority-inheritance locks were held. This situation is dealt with by making rcu_preempt_note_context_switch() check for negative ->rcu_read_lock_nesting, thus refraining from queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are already exiting from the outermost RCU read-side critical section (in other words, we really are no longer actually in that RCU read-side critical section). In addition, rcu_preempt_note_context_switch() invokes rcu_read_unlock_special() to carry out the cleanup in this case, which clears out the ->rcu_read_unlock_special bits and dequeues the task (if necessary), in turn avoiding needless delay of the current RCU grace period and needless RCU priority boosting. It is still illegal to call rcu_read_unlock() while holding a scheduler lock if the prior RCU read-side critical section has ever had either preemption or irqs enabled. However, the common use case is legal, namely where then entire RCU read-side critical section executes with irqs disabled, for example, when the scheduler lock is held across the entire lifetime of the RCU read-side critical section. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20sched: Avoid creating superfluous NUMA domains on non-NUMA systemsPeter Zijlstra1-0/+2
When creating sched_domains, stop when we've covered the entire target span instead of continuing to create domains, only to later find they're redundant and throw them away again. This avoids single node systems from touching funny NUMA sched_domain creation code and reduces the risks of the new SD_OVERLAP code. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Anton Blanchard <anton@samba.org> Cc: mahesh@linux.vnet.ibm.com Cc: benh@kernel.crashing.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20sched: Allow for overlapping sched_domain spansPeter Zijlstra3-29/+132
Allow for sched_domain spans that overlap by giving such domains their own sched_group list instead of sharing the sched_groups amongst each-other. This is needed for machines with more than 16 nodes, because sched_domain_node_span() will generate a node mask from the 16 nearest nodes without regard if these masks have any overlap. Currently sched_domains have a sched_group that maps to their child sched_domain span, and since there is no overlap we share the sched_group between the sched_domains of the various CPUs. If however there is overlap, we would need to link the sched_group list in different ways for each cpu, and hence sharing isn't possible. In order to solve this, allocate private sched_groups for each CPU's sched_domain but have the sched_groups share a sched_group_power structure such that we can uniquely track the power. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20sched: Break out cpu_power from the sched_group structurePeter Zijlstra3-34/+58
In order to prepare for non-unique sched_groups per domain, we need to carry the cpu_power elsewhere, so put a level of indirection in. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20Merge branch 'for-linus' of ↵Linus Torvalds1-7/+10
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: fix file mode calculation
2011-07-20Merge branch 'fixes' of ↵Linus Torvalds3-7/+24
git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc: davinci: DM365 EVM: fix video input mux bits ARM: davinci: Check for NULL return from irq_alloc_generic_chip arm: davinci: Fix low level gpio irq handlers' argument
2011-07-20vmscan: fix a livelock in kswapdShaohua Li1-1/+2
I'm running a workload which triggers a lot of swap in a machine with 4 nodes. After I kill the workload, I found a kswapd livelock. Sometimes kswapd3 or kswapd2 are keeping running and I can't access filesystem, but most memory is free. This looks like a regression since commit 08951e545918c159 ("mm: vmscan: correct check for kswapd sleeping in sleeping_prematurely"). Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0 for classzone_idx. The reason is end_zone in balance_pgdat() is 0 by default, if all zones have watermark ok, end_zone will keep 0. Later sleeping_prematurely() always returns true. Because this is an order 3 wakeup, and if classzone_idx is 0, both balanced_pages and present_pages in pgdat_balanced() are 0. We add a special case here. If a zone has no page, we think it's balanced. This fixes the livelock. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-20fs/libfs.c: fix simple_attr_write() on 32bit machinesAkinobu Mita1-1/+1
Assume that /sys/kernel/debug/dummy64 is debugfs file created by debugfs_create_x64(). # cd /sys/kernel/debug # echo 0x1234567812345678 > dummy64 # cat dummy64 0x0000000012345678 # echo 0x80000000 > dummy64 # cat dummy64 0xffffffff80000000 A value larger than INT_MAX cannot be written to the debugfs file created by debugfs_create_u64 or debugfs_create_x64 on 32bit machine. Because simple_attr_write() uses simple_strtol() for the conversion. To fix this, use simple_strtoll() instead. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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