user/sven/linux.git/Documentation/driver-api, branch v4.19.225

ata: make qc_prep return ata_completion_errors

2020-10-01T11:14:54Z

commit 95364f36701e62dd50eee91e1303187fd1a9f567 upstream. In case a driver wants to return an error from qc_prep, return enum ata_completion_errors. sata_mv is one of those drivers -- see the next patch. Other drivers return the newly defined AC_ERR_OK. [v2] use enum ata_completion_errors and AC_ERR_OK. Signed-off-by: Jiri Slaby Cc: Jens Axboe Cc: linux-ide@vger.kernel.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

mtd: rawnand: Pass a nand_chip object to nand_release()

2020-06-25T13:33:08Z

[ Upstream commit 59ac276f22270fb2094910f9a734c17f41c25e70 ] Let's make the raw NAND API consistent by patching all helpers to take a nand_chip object instead of an mtd_info one. Now is nand_release()'s turn. Signed-off-by: Boris Brezillon Signed-off-by: Miquel Raynal Signed-off-by: Sasha Levin

mtd: rawnand: Pass a nand_chip object to nand_scan()

2020-06-25T13:33:07Z

[ Upstream commit 00ad378f304a091ab2e2df5f944892a6ed558610 ] Let's make the raw NAND API consistent by patching all helpers to take a nand_chip object instead of an mtd_info one. We start with nand_scan(). Signed-off-by: Boris Brezillon Signed-off-by: Miquel Raynal Signed-off-by: Sasha Levin

driver core: Remove device link creation limitation

2020-03-20T10:55:58Z

commit 515db266a9dace92b0cbaed9a6044dd5304b8ca9 upstream. If device_link_add() is called for a consumer/supplier pair with an existing device link between them and the existing link's type is not in agreement with the flags passed to that function by its caller, NULL will be returned. That is seriously inconvenient, because it forces the callers of device_link_add() to worry about what others may or may not do even if that is not relevant to them for any other reasons. It turns out, however, that this limitation can be made go away relatively easily. The underlying observation is that if DL_FLAG_STATELESS has been passed to device_link_add() in flags for the given consumer/supplier pair at least once, calling either device_link_del() or device_link_remove() to release the link returned by it should work, but there are no other requirements associated with that flag. In turn, if at least one of the callers of device_link_add() for the given consumer/supplier pair has not passed DL_FLAG_STATELESS to it in flags, the driver core should track the status of the link and act on it as appropriate (ie. the link should be treated as "managed"). This means that DL_FLAG_STATELESS needs to be set for managed device links and it should be valid to call device_link_del() or device_link_remove() to drop references to them in certain sutiations. To allow that to happen, introduce a new (internal) device link flag called DL_FLAG_MANAGED and make device_link_add() set it automatically whenever DL_FLAG_STATELESS is not passed to it. Also make it take additional references to existing device links that were previously stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED unset) and will need to be managed going forward and initialize their status (which has been DL_STATE_NONE so far). Accordingly, when a managed device link is dropped automatically by the driver core, make it clear DL_FLAG_MANAGED, reset the link's status back to DL_STATE_NONE and drop the reference to it associated with DL_FLAG_MANAGED instead of just deleting it right away (to allow it to stay around in case it still needs to be released explicitly by someone). With that, since setting DL_FLAG_STATELESS doesn't mean that the device link in question is not managed any more, replace all of the status-tracking checks against DL_FLAG_STATELESS with analogous checks against DL_FLAG_MANAGED and update the documentation to reflect these changes. While at it, make device_link_add() reject flags that it does not recognize, including DL_FLAG_MANAGED. Signed-off-by: Rafael J. Wysocki Reviewed-by: Saravana Kannan Tested-by: Marek Szyprowski Review-by: Saravana Kannan Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER

2020-03-20T10:55:58Z

commit e7dd40105aac9ba051e44ad711123bc53a5e4c71 upstream. Add a new device link flag, DL_FLAG_AUTOPROBE_CONSUMER, to request the driver core to probe for a consumer driver automatically after binding a driver to the supplier device on a persistent managed device link. As unbinding the supplier driver on a managed device link causes the consumer driver to be detached from its device automatically, this flag provides a complementary mechanism which is needed to address some "composite device" use cases. Signed-off-by: Rafael J. Wysocki Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

driver core: Make driver core own stateful device links

2020-03-20T10:55:58Z

commit 72175d4ea4c442d95cf690c3e968eeee90fd43ca upstream. Even though stateful device links are managed by the driver core in principle, their creators are allowed and sometimes even expected to drop references to them via device_link_del() or device_link_remove(), but that doesn't really play well with the "persistent" link concept. If "persistent" managed device links are created from driver probe callbacks, device_link_add() called to do that will take a new reference on the link each time the callback runs and those references will never be dropped, which kind of isn't nice. This issues arises because of the link reference counting carried out by device_link_add() for existing links, but that is only done to avoid deleting device links that may still be necessary, which shouldn't be a concern for managed (stateful) links. These device links are managed by the driver core and whoever creates one of them will need it at least as long as until the consumer driver is detached from its device and deleting it may be left to the driver core just fine. For this reason, rework device_link_add() to apply the reference counting to stateless links only and make device_link_del() and device_link_remove() drop references to stateless links only too. After this change, if called to add a stateful device link for a consumer-supplier pair for which a stateful device link is present already, device_link_add() will return the existing link without incrementing its reference counter. Accordingly, device_link_del() and device_link_remove() will WARN() and do nothing when called to drop a reference to a stateful link. Thus, effectively, all stateful device links will be owned by the driver core. In addition, clean up the handling of the link management flags, DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER, so that (a) they are never set at the same time and (b) if device_link_add() is called for a consumer-supplier pair with an existing stateful link between them, the flags of that link will be combined with the flags passed to device_link_add() to ensure that the life time of the link is sufficient for all of the callers of device_link_add() for the same consumer-supplier pair. Update the device_link_add() kerneldoc comment to reflect the above changes. Signed-off-by: Rafael J. Wysocki Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

driver core: Fix adding device links to probing suppliers

2020-03-20T10:55:57Z

commit 15cfb094160385cc0b303c4cda483caa102af654 upstream. Currently, it is not valid to add a device link from a consumer driver ->probe callback to a supplier that is still probing too, but generally this is a valid use case. For example, if the consumer has just acquired a resource that can only be available if the supplier is functional, adding a device link to that supplier right away should be safe (and even desirable arguably), but device_link_add() doesn't handle that case correctly and the initial state of the link created by it is wrong then. To address this problem, change the initial state of device links added between a probing supplier and a probing consumer to DL_STATE_CONSUMER_PROBE and update device_links_driver_bound() to skip such links on the supplier side. With this change, if the supplier probe completes first, device_links_driver_bound() called for it will skip the link state update and when it is called for the consumer, the link state will be updated to "active". In turn, if the consumer probe completes first, device_links_driver_bound() called for it will change the state of the link to "active" and when it is called for the supplier, the link status update will be skipped. However, in principle the supplier or consumer probe may still fail after the link has been added, so modify device_links_no_driver() to change device links in the "active" or "consumer probe" state to "dormant" on the supplier side and update __device_links_no_driver() to change the link state to "available" only if it is "consumer probe" or "active". Then, if the supplier probe fails first, the leftover link to the probing consumer will become "dormant" and device_links_no_driver() called for the consumer (when its probe fails) will clean it up. In turn, if the consumer probe fails first, it will either drop the link, or change its state to "available" and, in the latter case, when device_links_no_driver() is called for the supplier, it will update the link state to "dormant". [If the supplier probe fails, but the consumer probe succeeds, which should not happen as long as the consumer driver is correct, the link still will be around, but it will be "dormant" until the supplier is probed again.] Signed-off-by: Rafael J. Wysocki Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

USB: core: Fix bug caused by duplicate interface PM usage counter

2019-05-08T05:21:44Z

commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream. The syzkaller fuzzer reported a bug in the USB hub driver which turned out to be caused by a negative runtime-PM usage counter. This allowed a hub to be runtime suspended at a time when the driver did not expect it. The symptom is a WARNING issued because the hub's status URB is submitted while it is already active: URB 0000000031fb463e submitted while active WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363 The negative runtime-PM usage count was caused by an unfortunate design decision made when runtime PM was first implemented for USB. At that time, USB class drivers were allowed to unbind from their interfaces without balancing the usage counter (i.e., leaving it with a positive count). The core code would take care of setting the counter back to 0 before allowing another driver to bind to the interface. Later on when runtime PM was implemented for the entire kernel, the opposite decision was made: Drivers were required to balance their runtime-PM get and put calls. In order to maintain backward compatibility, however, the USB subsystem adapted to the new implementation by keeping an independent usage counter for each interface and using it to automatically adjust the normal usage counter back to 0 whenever a driver was unbound. This approach involves duplicating information, but what is worse, it doesn't work properly in cases where a USB class driver delays decrementing the usage counter until after the driver's disconnect() routine has returned and the counter has been adjusted back to 0. Doing so would cause the usage counter to become negative. There's even a warning about this in the USB power management documentation! As it happens, this is exactly what the hub driver does. The kick_hub_wq() routine increments the runtime-PM usage counter, and the corresponding decrement is carried out by hub_event() in the context of the hub_wq work-queue thread. This work routine may sometimes run after the driver has been unbound from its interface, and when it does it causes the usage counter to go negative. It is not possible for hub_disconnect() to wait for a pending hub_event() call to finish, because hub_disconnect() is called with the device lock held and hub_event() acquires that lock. The only feasible fix is to reverse the original design decision: remove the duplicate interface-specific usage counter and require USB drivers to balance their runtime PM gets and puts. As far as I know, all existing drivers currently do this. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman

docs: fpga: document fpga manager flags

2018-09-30T15:49:55Z

Add flags #defines to kerneldoc documentation in a useful place. Signed-off-by: Alan Tull Acked-by: Moritz Fischer Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata

2018-08-24T20:20:33Z

Pull libata updates from Tejun Heo: "Nothing too interesting. Mostly ahci and ahci_platform changes, many around power management" * 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: (22 commits) ata: ahci_platform: enable to get and control reset ata: libahci_platform: add reset control support ata: add an extra argument to ahci_platform_get_resources() ata: sata_rcar: Add r8a77965 support ata: sata_rcar: exclude setting of PHY registers in Gen3 ata: sata_rcar: really mask all interrupts on Gen2 and later Revert "ata: ahci_platform: allow disabling of hotplug to save power" ata: libahci: Allow reconfigure of DEVSLP register ata: libahci: Correct setting of DEVSLP register ata: ahci: Enable DEVSLP by default on x86 with SLP_S0 ata: ahci: Support state with min power but Partial low power state Revert "ata: ahci_platform: convert kcalloc to devm_kcalloc" ata: sata_rcar: Add rudimentary Runtime PM support ata: sata_rcar: Provide a short-hand for &pdev->dev ata: Only output sg element mapped number in verbose debug ata: Guard ata_scsi_dump_cdb() by ATA_VERBOSE_DEBUG ata: ahci_platform: convert kcalloc to devm_kcalloc ata: ahci_platform: convert kzallloc to kcalloc ata: ahci_platform: correct parameter documentation for ahci_platform_shutdown libata: remove ata_sff_data_xfer_noirq() ...