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path: root/include/linux/libata.h
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2006-07-19[PATCH] libata: improve EH action and EHI flag handlingTejun Heo
Update ata_eh_about_to_do() and ata_eh_done() to improve EH action and EHI flag handling. * There are two types of EHI flags - one which expires on successful EH and the other which expires on a successful reset. Make this distinction clear. * Unlike other EH actions, reset actions are represented by two EH action masks and a EHI modifier. Implement correct about_to_do/done semantics for resets. That is, prior to reset, related EH info is sucked in from ehi and cleared, and after reset is complete, related EH info in ehc is cleared. These changes improve consistency and remove unnecessary EH actions caused by stale EH action masks and EHI flags. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: reimplement controller-wide PMTejun Heo
Reimplement controller-wide PM. ata_host_set_suspend/resume() are defined to suspend and resume a host_set. While suspended, EHs for all ports in the host_set are pegged using ATA_FLAG_SUSPENDED and frozen. Because SCSI device hotplug is done asynchronously against the rest of libata EH and the same mutex is used when adding new device, suspend cannot wait for hotplug to complete. So, if SCSI device hotplug is in progress, suspend fails with -EBUSY. In most cases, host_set resume is followed by device resume. As each resume operation requires a reset, a single host_set-wide resume operation may result in multiple resets. To avoid this, resume waits upto 1 second giving PM to request resume for devices. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: reimplement per-dev PMTejun Heo
Reimplement per-dev PM. The original implementation directly put the device into suspended mode and didn't synchronize w/ EH operations including hotplug. This patch reimplements ata_scsi_device_suspend() and ata_scsi_device_resume() such that they request EH to perform the respective operations. Both functions synchronize with hotplug such that it doesn't operate on detached devices. Suspend waits for completion but resume just issues request and returns. This allows parallel wake up of devices and thus speeds up system resume. Due to sdev detach synchronization, it's not feasible to separate out EH requesting from sdev handling; thus, ata_device_suspend/resume() are removed and everything is implemented in the respective libata-scsi functions. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: implement PM EH actionsTejun Heo
Implement two PM per-dev EH actions - ATA_EH_SUSPEND and ATA_EH_RESUME. Each action puts the target device into suspended mode and resumes from it respectively. Once a device is put to suspended mode, no EH operations other than RESUME is allowed on the device. The device will stay suspended till it gets resumed and thus reset and revalidated. To implement this, a new device state helper - ata_dev_ready() - is implemented and used in EH action implementations to make them operate only on attached & running devices. If all possible devices on a port are suspended, reset is skipped too. This prevents spurious events including hotplug events from disrupting suspended devices. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: separate out __ata_ehi_hotplugged()Tejun Heo
Separate out __ata_ehi_hotplugged() from ata_ehi_hotplugged(). The underscored version doesn't set AC_ERR_ATA_BUS. This will be used for resume which is a hotplug event but not an ATA bus error. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: implement ATA_EHI_NO_AUTOPSY and QUIETTejun Heo
Implement ATA_EHI_NO_AUTOPSY and QUIET. These used to be implied by ATA_PFLAG_LOADING, but new power management and PMP support need to use these separately. e.g. Suspend/resume operations shouldn't print full EH messages and resume shouldn't be recorded as an error. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: clean up debounce parameters and improve parameter selectionTejun Heo
The names of predefined debounce timing parameters didn't exactly match their usages. Rename to more generic names and implement param selection helper sata_ehc_deb_timing() which uses EHI_HOTPLUGGED to select params. Combined with the previous EHI_RESUME_LINK differentiation, this makes parameter selection accurate. e.g. user scan resumes link but normal deb param is used instead of hotplug param. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: implement ATA_EHI_RESUME_LINKTejun Heo
Implement ATA_EHI_RESUME_LINK, which indicates that the link needs to be resumed. This used to be implied by ATA_EHI_HOTPLUGGED. However, hotplug isn't the only event which requires link resume and separating this out allows other places to request link resume. This differentiation also allows better debounce timing selection. This patch converts user scan to use ATA_EHI_RESUME_LINK. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-05[PATCH] libata: add ap->pflags and move core dynamic flags to itTejun Heo
ap->flags is way too clamped. Separate out core dynamic flags to ap->pflags. ATA_FLAG_DISABLED is a dynamic flag but left alone as it's referenced by a lot of LLDs and it's gonna be removed once all LLDs are converted to new EH. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-26[PATCH] libata: implement ata_port_max_devices()Tejun Heo
Implement ata_port_max_devices(). This function returns the number of possible devices on a port. This will be used by new PM implementation. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-26[PATCH] libata.h needs scatterlist.hAndrew Morton
From: Andrew Morton <akpm@osdl.org> s390: In file included from drivers/scsi/libata-bmdma.c:39: include/linux/libata.h:391: error: field 'sgent' has incomplete type include/linux/libata.h:392: error: field 'pad_sgent' has incomplete type include/linux/libata.h: In function 'ata_sg_is_last': include/linux/libata.h:849: error: arithmetic on pointer to an incomplete type include/linux/libata.h:849: error: arithmetic on pointer to an incomplete type include/linux/libata.h: In function 'ata_qc_next_sg': include/linux/libata.h:869: error: increment of pointer to unknown structure include/linux/libata.h:869: error: arithmetic on pointer to an incomplete type include/linux/libata.h:869: error: arithmetic on pointer to an incomplete type include/linux/libata.h:869: error: arithmetic on pointer to an incomplete type Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-22[libata] Add host lock to struct ata_portJeff Garzik
Prepare for changes required to support SATA devices attached to SAS HBAs. For these devices we don't want to use host_set at all, since libata will not be the owner of struct scsi_host. Signed-off-by: Brian King <brking@us.ibm.com> (with slight merge modifications made by...) Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-22[PATCH] libata: implement per-dev EH action mask eh_info->dev_action[]Tejun Heo
Currently, the only per-dev EH action is REVALIDATE. EH used to exploit ehi->dev to do selective revalidation on a ATA bus. However, this is a bit hacky and makes it impossible to request selective revalidation from outside of EH or add another per-dev EH action. This patch adds per-dev EH action mask eh_info->dev_action[] and update EH to use this field for REVALIDATE. Note that per-dev actions can still be specified at port-level and it has the same effect of specifying the action for all devices on the port. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-12[PATCH] libata: add host_set->next for legacy two host_sets case, take #3Tejun Heo
For a legacy ATA controller, libata registers two separate host sets. There was no connection between the two hosts making it impossible to traverse all ports related to the controller. This patch adds host_set->next which points to the second host_set and makes ata_pci_remove_one() remove all associated host_sets. * On device removal, all ports hanging off the device are properly detached. Prior to this patch, ports on the first host_set weren't detached casuing oops on driver unloading. * On device removal, both host_sets are properly freed This will also be used by new power management code to suspend and resume all ports of a controller. host_set/port representation will be improved to handle legacy controllers better and this host_set linking will go away with it. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-06-12libata: fix build, by adding required workqueue member to port structJeff Garzik
2006-06-11[PATCH] libata: cosmetic change in struct ata_portTejun Heo
Cosmetic change in struct ata_port. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp: killl ops->probe_resetTejun Heo
Now that all drivers implementing new EH are converted to new probing mechanism, ops->probe_reset doesn't have any user. Kill it. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp: update unload-unplugTejun Heo
Update unload unplug - driver unloading / PCI removal. This is done by ata_port_detach() which short-circuits EH, disables all devices and freezes the port. With this patch, EH and unloading/unplugging are properly synchronized. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp: implement warmplugTejun Heo
Implement warmplug. User-initiated unplug can be detected by hostt->slave_destroy() and plug by transportt->user_scan(). This patch only implements the two callbacks. The next function will hook them. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp: implement SCSI part of hotplugTejun Heo
Implement SCSI part of hotplug. This must be done in a separate context as SCSI makes use of EH during probing. SCSI scan fails silently if EH is in progress. In such cases, libata pauses briefly and retries until every device is attached. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp: implement hotplugTejun Heo
Implement ATA part of hotplug. To avoid probing broken devices over and over again, disabled devices are not automatically detached. They are detached only if probing is requested for the device or the associated port is offline. Also, to avoid infinite probing loop, Each device is probed only once per EH run. As SATA PHY status is fragile, devices are detached only after it has used up its recovery chances unless explicitly requested by LLDD or user (LLDD may request direct detach if, for example, it supports cold presence detection). Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata: export ata_hsm_move()Tejun Heo
ata_hsm_move() will be used by LLDDs which depend on standard PIO HSM but implement their own interrupt handlers. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: add prereset() method and implement ata_std_prereset()Tejun Heo
With hotplug, every reset might be a probing reset and thus something similar to probe_init() is needed. prereset() method is called before a series of resets to a port and is the counterpart of postreset(). prereset() can tell EH to use different type of reset or skip reset by modifying ehc->i.action. This patch also implements ata_std_prereset(). Most controllers should be able to use this function directly or with some wrapping. After hotplug, different controllers need different actions to resume the PHY and detect the newly attached device. Controllers can be categorized as follows. * Controllers which can wait for the first D2H FIS after hotplug. Note that if the waiting is implemented by polling TF status, there needs to be a way to set BSY on PHY status change. It can be implemented by hardware or with the help of the driver. * Controllers which can wait for the first D2H FIS after sending COMRESET. These controllers need to issue COMRESET to wait for the first FIS. Note that the received D2H FIS could be the first D2H FIS after POR (power-on-reset) or D2H FIS in response to the COMRESET. Some controllers use COMRESET as TF status synchronization point and clear TF automatically (sata_sil). * Controllers which cannot wait for the first D2H FIS reliably. Blindly issuing SRST to spinning-up device often results in command issue failure or timeout, causing extended delay. For these controllers, ata_std_prereset() explicitly waits ATA_SPINUP_WAIT (currently 8s) to give newly attached device time to spin up, then issues reset. Note that failing to getting ready in ATA_SPINUP_WAIT is not critical. libata will retry. So, the timeout needs to be long enough to spin up most devices. LLDDs can tell ata_std_prereset() which of above action is needed with ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_SKIP_D2H_BSY flags. These flags are PHY-specific property and will be moved to ata_link later. While at it, this patch unifies function typedef's such that they all have named arguments. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: implement sata_phy_debounce()Tejun Heo
With hotplug, PHY always needs to be debounced before a reset as any reset might find new devices. Extract PHY waiting code from sata_phy_resume() and extend it to include SStatus debouncing. Note that sata_phy_debounce() is superset of what used to be done inside sata_phy_resume(). Three default debounce timing parameters are defined to be used by hot/boot plug. As resume failure during probing will be properly handled as errors, timeout doesn't have to be long as before. probeinit() uses the same timeout to retain the original behavior. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: store attached SCSI deviceTejun Heo
Add device persistent field dev->sdev and store the attached SCSI device. With hotplug, libata needs to know the attached SCSI device to offline and detach it, but scsi_device_lookup() cannot be used because libata will reuse SCSI ID numbers - dead but not gone devices (due to zombie opens, etc...) interfere with the lookup. dev->sdev doesn't hold reference to the SCSI device. It's cleared when the SCSI device goes away. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: implement ap->hw_sata_spd_limitTejun Heo
Add ap->hw_sata_spd_limit and initialize it once during the boot initialization (or driver load initialization). ap->sata_spd_limit is reset to ap->hw_sata_spd_limit on hotplug. This prevents spd limits introduced by earlier devices from affecting new devices. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: make some ata_device fields persistentTejun Heo
Lifetimes of some fields span over device plugging/unplugging. This patch moves such persistent fields to the top of ata_device and separate them with ATA_DEVICE_CLEAR_OFFSET. Fields above the offset are initialized once during host initializatino while all other fields are cleared before hotplugging. Currently ->ap, devno and part of flags are persistent. Note that flags is partially cleared while holding host_set lock. This is to synchronize with later warm plug implementation which will record hotplug request in dev->flags. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata-hp-prep: add flags and eh_info/context fields for hotplugTejun Heo
Add hotplug related flags and eh_info/context fields. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata: implement ata_eh_wait()Tejun Heo
Implement ata_eh_wait(). On return from this function, it's guaranteed that the EH which was pending or in progress when the function was called is complete - including the tailing part of SCSI EH. This will be used by hotplug and others to synchronize with EH. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-31[PATCH] libata: shift host flag constantsTejun Heo
Nudge host flag constants to make a room after ATA_FLAG_EH_PENDING. New EH flag will be added. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-26[PATCH] libata: add pio_data_xfer_noirqAlan Cox
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-05-24[PATCH] libata: Remove obsolete flagAlan Cox
ATA_FLAG_IRQ_MASK was added when I did the original data transfer with IRQ masked bits for PIO. It has since been replaced by ->pio_data_xfer methods so should be removed so nobody uses it by mistake thinking it still works. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-05-24[PATCH] PATCH: libata. Add ->data_xfer methodAlan Cox
We need to pass the device in order to do per device checks such as 32bit I/O enables. With the changes to include dev->ap we now don't have to add parameters however just clean them up. Also add data_xfer methods to the existing drivers except ata_piix (which is in the other block of patches). If you reject the piix one just add a data_xfer to it... Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-05-20[PATCH] libata: Fix the HSM error_mask mapping (was: Re: libata-tj and SMART)Albert Lee
Fix the HSM error_mask mapping. Changes: - Better mapping in ac_err_mask() - In HSM_ST_FIRST ans HSM_ST state, check ATA_ERR|ATA_DF and map it to AC_ERR_DEV instead of AC_ERR_HSM. - In HSM_ST_FIRST and HSM_ST state, map DRQ=1 ERR=1 to AC_ERR_HSM. - For PIO data in and DRQ=1 ERR=1, add check after the junk data block is read. Signed-off-by: Albert Lee <albertcc@tw.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-05-15Merge branch 'max-sect' into upstreamJeff Garzik
2006-05-15[PATCH] libata-ncq: implement NCQ device configurationTejun Heo
Now that all NCQ related stuff are in place, implement NCQ device configuration and bump ATA_MAX_QUEUE to 32 thus activating NCQ support. Original implementation is from Jens Axboe. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-ncq: implement ap->qc_active, ap->sactive and complete helperTejun Heo
Add ap->qc_active and ap->sactive, mask of all active qcs and libata's view of the SActive register, respectively. Also, implement ata_qc_complete_multiple() which takes new qc_active mask and complete multiple qcs according to the mask. These will be used to track NCQ commands and complete them. The distinction between ap->qc_active and ap->sactive is also useful for later PM implementation. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-ncq: rename ap->qactive to ap->qc_allocatedTejun Heo
Rename ap->qactive to ap->qc_allocated. This is to accomodate addition of ap->qc_active, mask of active qcs. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-ncq: add NCQ related ATA/libata constants and macrosTejun Heo
Add NCQ related ATA/libata constants and macros. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15Merge branch 'irq-pio'Tejun Heo
Conflicts: drivers/scsi/libata-core.c include/linux/libata.h
2006-05-15[PATCH] libata-eh: implement BMDMA EHTejun Heo
Implement stock BMDMA error handling methods. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh: implement new EHTejun Heo
Implement new EH. The exported interface is ata_do_eh() which is to be called from ->error_handler and performs the following steps to recover the failed port. ata_eh_autopsy() : analyze SError/TF, determine the cause of failure and required recovery actions and record it in ap->eh_context ata_eh_report() : report the failure to user ata_eh_recover() : perform recovery actions described in ap->eh_context ata_eh_finish() : finish failed qcs LLDDs can customize error handling by modifying eh_context before calling ata_do_eh() or, if necessary, doing so inbetween each major steps by calling each step explicitly. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh: implement ata_eh_info and ata_eh_contextTejun Heo
struct ata_eh_info serves as the communication channel between execution path and EH. Execution path describes detected error condition in ap->eh_info and EH recovers the port using it. To avoid missing error conditions detected during EH, EH makes its own copy of eh_info and clears it on entry allowing error info to accumulate during EH. Most EH states including EH's copy of eh_info are stored in ap->eh_context (struct ata_eh_context) which is owned by EH and thus doesn't require any synchronization to access and alter. This standardized context makes it easy to integrate various parts of EH and extend EH to handle multiple links (for PM). Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh: implement dev->eringTejun Heo
This patch implements ata_ering and uses it to define dev->ering. ata_ering is a ring buffer which records libata errors - whether a command was for normar IO request, err_mask and timestamp. Errors are recorded per-device in dev->ering. This will be used by EH to determine recovery actions. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh: add ATA and libata flags for new EHTejun Heo
Add ATA and libata flags to be used by new EH. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh-fw: update ata_scsi_error() for new EHTejun Heo
Update ata_scsi_error() for new EH. ata_scsi_error() is responsible for claiming timed out qcs and invoking ->error_handler in safe and synchronized manner. As the state of the controller is unknown if a qc has timed out, the port is frozen in such cases. Note that ata_scsi_timed_out() isn't used for new EH. This is because a timed out qc cannot be claimed by EH without freezing the port and freezing the port in ata_scsi_timed_out() results in unnecessary abortion of other active qcs. ata_scsi_timed_out() can be removed once all drivers are converted to new EH. While at it, add 'TODO: kill' comments to old EH functions. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh-fw: implement freeze/thawTejun Heo
Freezing is performed atomic w.r.t. host_set->lock and once frozen LLDD is not allowed to access the port or any qc on it. Also, libata makes sure that no new qc gets issued to a frozen port. A frozen port is thawed after a reset operation completes successfully, so reset methods must do its job while the port is frozen. During initialization all ports get frozen before requesting IRQ, so reset methods are always invoked on a frozen port. Optional ->freeze and ->thaw operations notify LLDD that the port is being frozen and thawed, respectively. LLDD can disable/enable hardware interrupt in these callbacks if the controller's IRQ mask can be changed dynamically. If the controller doesn't allow such operation, LLDD can check for frozen state in the interrupt handler and ack/clear interrupts unconditionally while frozen. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh-fw: implement ata_port_schedule_eh() and ata_port_abort()Tejun Heo
ata_port_schedule_eh() directly schedules EH for @ap without associated qc. Once EH scheduled, no further qc is allowed and EH kicks in as soon as all currently active qc's are drained. ata_port_abort() schedules all currently active commands for EH by qc_completing them with ATA_QCFLAG_FAILED set. If ata_port_abort() doesn't find any qc to abort, it directly schedule EH using ata_port_schedule_eh(). These two functions provide ways to invoke EH for conditions which aren't directly related to any specfic qc. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh-fw: implement new EH scheduling via error completionTejun Heo
There are several ways a qc can get schedule for EH in new EH. This patch implements one of them - completing a qc with ATA_QCFLAG_FAILED set or with non-zero qc->err_mask. ALL such qc's are examined by EH. New EH schedules a qc for EH from completion iff ->error_handler is implemented, qc is marked as failed or qc->err_mask is non-zero and the command is not an internal command (internal cmd is handled via ->post_internal_cmd). The EH scheduling itself is performed by asking SCSI midlayer to schedule EH for the specified scmd. For drivers implementing old-EH, nothing changes. As this change makes ata_qc_complete() rather large, it's not inlined anymore and __ata_qc_complete() is exported to other parts of libata for later use. Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15[PATCH] libata-eh-fw: update ata_qc_from_tag() to enforce normal/EH qc ownershipTejun Heo
New EH framework has clear distinction about who owns a qc. Every qc starts owned by normal execution path - PIO, interrupt or whatever. When an exception condition occurs which affects the qc, the qc gets scheduled for EH. Note that some events (say, link lost and regained, command timeout) may schedule qc's which are not directly related but could have been affected for EH too. Scheduling for EH is atomic w.r.t. ap->host_set->lock and once schedule for EH, normal execution path is not allowed to access the qc in whatever way. (PIO synchronization acts a bit different and will be dealt with later) This patch make ata_qc_from_tag() check whether a qc is active and owned by normal path before returning it. If conditions don't match, NULL is returned and thus access to the qc is denied. __ata_qc_from_tag() is the original ata_qc_from_tag() and is used by libata core/EH layers to access inactive/failed qc's. This change is applied only if the associated LLDD implements new EH as indicated by non-NULL ->error_handler Signed-off-by: Tejun Heo <htejun@gmail.com>