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* xen/xenbus: Rename *RING_PAGE* to *RING_GRANT*Julien Grall2015-10-232-5/+5
| | | | | | | | Linux may use a different page size than the size of grant. So make clear that the order is actually in number of grant. Signed-off-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* block/xen-blkback: Make it running on 64KB page granularityJulien Grall2015-10-233-9/+22
| | | | | | | | | | | | | | | | | | | The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity behaving as a block backend on a non-modified Xen. It's only necessary to adapt the ring size and the number of request per indirect frames. The rest of the code is relying on the grant table code. Note that the grant table code is allocating a Linux page per grant which will result to waste 6OKB for every grant when Linux is using 64KB page granularity. This could be improved by sharing the page between multiple grants. Signed-off-by: Julien Grall <julien.grall@citrix.com> Acked-by: "Roger Pau Monné" <roger.pau@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* Merge branch 'stable/for-jens-4.3' of ↵Jens Axboe2015-09-231-18/+20
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus Konrad writes: It has one fix that should go in and also be put in stable tree (I've added the CC already). It is a fix for a memory leak that can exposed via using UEFI xen-blkfront driver.
| * xen/blkback: free requests on disconnectionRoger Pau Monne2015-09-231-18/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is due to commit 86839c56dee28c315a4c19b7bfee450ccd84cd25 "xen/block: add multi-page ring support" When using an guest under UEFI - after the domain is destroyed the following warning comes from blkback. ------------[ cut here ]------------ WARNING: CPU: 2 PID: 95 at /home/julien/works/linux/drivers/block/xen-blkback/xenbus.c:274 xen_blkif_deferred_free+0x1f4/0x1f8() Modules linked in: CPU: 2 PID: 95 Comm: kworker/2:1 Tainted: G W 4.2.0 #85 Hardware name: APM X-Gene Mustang board (DT) Workqueue: events xen_blkif_deferred_free Call trace: [<ffff8000000890a8>] dump_backtrace+0x0/0x124 [<ffff8000000891dc>] show_stack+0x10/0x1c [<ffff8000007653bc>] dump_stack+0x78/0x98 [<ffff800000097e88>] warn_slowpath_common+0x9c/0xd4 [<ffff800000097f80>] warn_slowpath_null+0x14/0x20 [<ffff800000557a0c>] xen_blkif_deferred_free+0x1f0/0x1f8 [<ffff8000000ad020>] process_one_work+0x160/0x3b4 [<ffff8000000ad3b4>] worker_thread+0x140/0x494 [<ffff8000000b2e34>] kthread+0xd8/0xf0 ---[ end trace 6f859b7883c88cdd ]--- Request allocation has been moved to connect_ring, which is called every time blkback connects to the frontend (this can happen multiple times during a blkback instance life cycle). On the other hand, request freeing has not been moved, so it's only called when destroying the backend instance. Due to this mismatch, blkback can allocate the request pool multiple times, without freeing it. In order to fix it, move the freeing of requests to xen_blkif_disconnect to restore the symmetry between request allocation and freeing. Reported-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Tested-by: Julien Grall <julien.grall@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: xen-devel@lists.xenproject.org CC: stable@vger.kernel.org # 4.2 Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-blockLinus Torvalds2015-09-021-2/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block updates from Jens Axboe: "This first core part of the block IO changes contains: - Cleanup of the bio IO error signaling from Christoph. We used to rely on the uptodate bit and passing around of an error, now we store the error in the bio itself. - Improvement of the above from myself, by shrinking the bio size down again to fit in two cachelines on x86-64. - Revert of the max_hw_sectors cap removal from a revision again, from Jeff Moyer. This caused performance regressions in various tests. Reinstate the limit, bump it to a more reasonable size instead. - Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me. Most devices have huge trim limits, which can cause nasty latencies when deleting files. Enable the admin to configure the size down. We will look into having a more sane default instead of UINT_MAX sectors. - Improvement of the SGP gaps logic from Keith Busch. - Enable the block core to handle arbitrarily sized bios, which enables a nice simplification of bio_add_page() (which is an IO hot path). From Kent. - Improvements to the partition io stats accounting, making it faster. From Ming Lei. - Also from Ming Lei, a basic fixup for overflow of the sysfs pending file in blk-mq, as well as a fix for a blk-mq timeout race condition. - Ming Lin has been carrying Kents above mentioned patches forward for a while, and testing them. Ming also did a few fixes around that. - Sasha Levin found and fixed a use-after-free problem introduced by the bio->bi_error changes from Christoph. - Small blk cgroup cleanup from Viresh Kumar" * 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits) blk: Fix bio_io_vec index when checking bvec gaps block: Replace SG_GAPS with new queue limits mask block: bump BLK_DEF_MAX_SECTORS to 2560 Revert "block: remove artifical max_hw_sectors cap" blk-mq: fix race between timeout and freeing request blk-mq: fix buffer overflow when reading sysfs file of 'pending' Documentation: update notes in biovecs about arbitrarily sized bios block: remove bio_get_nr_vecs() fs: use helper bio_add_page() instead of open coding on bi_io_vec block: kill merge_bvec_fn() completely md/raid5: get rid of bio_fits_rdev() md/raid5: split bio for chunk_aligned_read block: remove split code in blkdev_issue_{discard,write_same} btrfs: remove bio splitting and merge_bvec_fn() calls bcache: remove driver private bio splitting code block: simplify bio_add_page() block: make generic_make_request handle arbitrarily sized bios blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL) block: don't access bio->bi_error after bio_put() block: shrink struct bio down to 2 cache lines again ...
| * | block: add a bi_error field to struct bioChristoph Hellwig2015-07-291-2/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | Merge branch 'stable/for-jens-4.2' of ↵Jens Axboe2015-07-271-2/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus Konrad writes: "There are three bugs that have been found in the xen-blkfront (and backend). Two of them have the stable tree CC-ed. They have been found where an guest is migrating to a host that is missing 'feature-persistent' support (from one that has it enabled). We end up hitting an BUG() in the driver code."
| * xen-blkback: replace work_pending with work_busy in purge_persistent_gnt()Bob Liu2015-07-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The BUG_ON() in purge_persistent_gnt() will be triggered when previous purge work haven't finished. There is a work_pending() before this BUG_ON, but it doesn't account if the work is still currently running. CC: stable@vger.kernel.org Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | Merge tag 'for-linus-4.2-rc0-tag' of ↵Linus Torvalds2015-07-012-6/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from David Vrabel: "Xen features and cleanups for 4.2-rc0: - add "make xenconfig" to assist in generating configs for Xen guests - preparatory cleanups necessary for supporting 64 KiB pages in ARM guests - automatically use hvc0 as the default console in ARM guests" * tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: block/xen-blkback: s/nr_pages/nr_segs/ block/xen-blkfront: Remove invalid comment block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS arm/xen: Drop duplicate define mfn_to_virt xen/grant-table: Remove unused macro SPP xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring xen: Include xen/page.h rather than asm/xen/page.h kconfig: add xenconfig defconfig helper kconfig: clarify kvmconfig is for kvm xen/pcifront: Remove usage of struct timeval xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON() hvc_xen: avoid uninitialized variable warning xenbus: avoid uninitialized variable warning xen/arm: allow console=hvc0 to be omitted for guests arm,arm64/xen: move Xen initialization earlier arm/xen: Correctly check if the event channel interrupt is present
| * | block/xen-blkback: s/nr_pages/nr_segs/Julien Grall2015-06-172-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make the code less confusing to read now that Linux may not have the same page size as Xen. Signed-off-by: Julien Grall <julien.grall@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* | | Merge branch 'stable/for-jens-4.2' of ↵Jens Axboe2015-06-273-63/+121
|\ \ \ | |/ / |/| / | |/ git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus
| * xen/block: add multi-page ring supportBob Liu2015-06-063-20/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend xen/block to support multi-page ring, so that more requests can be issued by using more than one pages as the request ring between blkfront and backend. As a result, the performance can get improved significantly. We got some impressive improvements on our highend iscsi storage cluster backend. If using 64 pages as the ring, the IOPS increased about 15 times for the throughput testing and above doubled for the latency testing. The reason was the limit on outstanding requests is 32 if use only one-page ring, but in our case the iscsi lun was spread across about 100 physical drives, 32 was really not enough to keep them busy. Changes in v2: - Rebased to 4.0-rc6. - Document on how multi-page ring feature working to linux io/blkif.h. Changes in v3: - Remove changes to linux io/blkif.h and follow the protocol defined in io/blkif.h of XEN tree. - Rebased to 4.1-rc3 Changes in v4: - Turn to use 'ring-page-order' and 'max-ring-page-order'. - A few comments from Roger. Changes in v5: - Clarify with 4k granularity to comment - Address more comments from Roger Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * drivers: xen-blkback: delay pending_req allocation to connect_ringBob Liu2015-06-062-45/+39Star
| | | | | | | | | | | | | | | | | | This is a pre-patch for multi-page ring feature. In connect_ring, we can know exactly how many pages are used for the shared ring, delay pending_req allocation here so that we won't waste too much memory. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/grant: introduce func gnttab_unmap_refs_sync()Bob Liu2015-04-271-28/+3Star
| | | | | | | | | | | | | | | | | | | | | | There are several place using gnttab async unmap and wait for completion, so move the common code to a function gnttab_unmap_refs_sync(). Signed-off-by: Bob Liu <bob.liu@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* | xen/blkback: safely unmap purge persistent grantsBob Liu2015-04-271-6/+18
|/ | | | | | | | | | | | Commit c43cf3ea8385 ("xen-blkback: safely unmap grants in case they are still in use") use gnttab_unmap_refs_async() to wait until the mapped pages are no longer in use before unmapping them, but that commit missed the persistent case. Purge persistent pages can't be unmapped either unless no longer in use. Signed-off-by: Bob Liu <bob.liu@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* Merge branch 'for-4.1/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2015-04-173-52/+54
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block driver updates from Jens Axboe: "This is the block driver pull request for 4.1. As with the core bits, this is a relatively slow round. This pull request contains: - Various fixes and cleanups for NVMe, from Alexey Khoroshilov, Chong Yuan, myself, Keith Busch, and Murali Iyer. - Documentation and code cleanups for nbd from Markus Pargmann. - Change of brd maintainer to me, from Ross Zwisler. At least the email doesn't bounce anymore then. - Two xen-blkback fixes from Tao Chen" * 'for-4.1/drivers' of git://git.kernel.dk/linux-block: (23 commits) NVMe: Meta data handling through submit io ioctl NVMe: Add translation for block limits NVMe: Remove check for null NVMe: Fix error handling of class_create("nvme") xen-blkback: define pr_fmt macro to avoid the duplication of DRV_PFX xen-blkback: enlarge the array size of blkback name nbd: Return error pointer directly nbd: Return error code directly nbd: Remove fixme that was already fixed nbd: Restructure debugging prints nbd: Fix device bytesize type nbd: Replace kthread_create with kthread_run nbd: Remove kernel internal header Documentation: nbd: Add list of module parameters Documentation: nbd: Reformat to allow more documentation NVMe: increase depth of admin queue nvme: Fix PRP list calculation for non-4k system page size NVMe: Fix blk-mq hot cpu notification NVMe: embedded iod mask cleanup NVMe: Freeze admin queue on device failure ...
| * xen-blkback: define pr_fmt macro to avoid the duplication of DRV_PFXTao Chen2015-04-073-50/+49Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define pr_fmt macro with {xen-blkback: } prefix, then remove all use of DRV_PFX in the pr sentences. Replace all DPRINTK with pr sentences, and get rid of DPRINTK macro. It will simplify the code. And if the pr sentences miss a \n, add it in the end. If the DPRINTK sentences have redundant \n, remove it. It will format the code. These all make the readability of the code become better. Signed-off-by: Tao Chen <boby.chen@huawei.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
| * xen-blkback: enlarge the array size of blkback nameTao Chen2015-04-071-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | The blkback name is like blkback.domid.xvd[a-z], if domid has four digits (means larger than 1000), then the backmost xvd wouldn't be fully shown. Define a BLKBACK_NAME_LEN macro to be 20, enlarge the array size of blkback name, so it will be fully shown in any case. Signed-off-by: Tao Chen <boby.chen@huawei.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
* | xenbus_client: Extend interface to support multi-page ringWei Liu2015-04-151-2/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | Originally Xen PV drivers only use single-page ring to pass along information. This might limit the throughput between frontend and backend. The patch extends Xenbus driver to support multi-page ring, which in general should improve throughput if ring is the bottleneck. Changes to various frontend / backend to adapt to the new interface are also included. Affected Xen drivers: * blkfront/back * netfront/back * pcifront/back * scsifront/back * vtpmfront The interface is documented, as before, in xenbus_client.c. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Cc: Konrad Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* Merge branch 'for-3.20/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2015-02-122-2/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block driver changes from Jens Axboe: "This contains: - The 4k/partition fixes for brd from Boaz/Matthew. - A few xen front/back block fixes from David Vrabel and Roger Pau Monne. - Floppy changes from Takashi, cleaning the device file creation. - Switching libata to use the new blk-mq tagging policy, removing code (and a suboptimal implementation) from libata. This will throw you a merge conflict, since a bug in the original libata tagging code was fixed since this code was branched. Trivial. From Shaohua. - Conversion of loop to blk-mq, from Ming Lei. - Cleanup of the io_schedule() handling in bsg from Peter Zijlstra. He claims it improves on unreadable code, which will cost him a beer. - Maintainer update or NDB, now handled by Markus Pargmann. - NVMe: - Optimization from me that avoids a kmalloc/kfree per IO for smaller (<= 8KB) IO. This cuts about 1% of high IOPS CPU overhead. - Removal of (now) dead RCU code, a relic from before NVMe was converted to blk-mq" * 'for-3.20/drivers' of git://git.kernel.dk/linux-block: xen-blkback: default to X86_32 ABI on x86 xen-blkfront: fix accounting of reqs when migrating xen-blkback,xen-blkfront: add myself as maintainer block: Simplify bsg complete all floppy: Avoid manual call of device_create_file() NVMe: avoid kmalloc/kfree for smaller IO MAINTAINERS: Update NBD maintainer libata: make sata_sil24 use fifo tag allocator libata: move sas ata tag allocation to libata-scsi.c libata: use blk taging NVMe: within nvme_free_queues(), delete RCU sychro/deferred free null_blk: suppress invalid partition info brd: Request from fdisk 4k alignment brd: Fix all partitions BUGs axonram: Fix bug in direct_access loop: add blk-mq.h include block: loop: don't handle REQ_FUA explicitly block: loop: introduce lo_discard() and lo_req_flush() block: loop: say goodby to bio block: loop: improve performance via blk-mq
| * xen-blkback: default to X86_32 ABI on x86David Vrabel2015-02-102-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | Prior to the existance of 64-bit backends using the X86_64 ABI, frontends used the X86_32 ABI. These old frontends do not specify the ABI and when used with a 64-bit backend do not work. On x86, default to the X86_32 ABI if one is not specified. Backends on ARM continue to default to their NATIVE ABI. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
* | xen-blkback: safely unmap grants in case they are still in useJennifer Herbert2015-01-282-50/+122
| | | | | | | | | | | | | | | | | | | | | | | | | | Use gnttab_unmap_refs_async() to wait until the mapped pages are no longer in use before unmapping them. This allows blkback to use network storage which may retain refs to pages in queued skbs after the block I/O has completed. Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Jens Axboe <axboe@kernel.de> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* | xen/grant-table: add helpers for allocating pagesDavid Vrabel2015-01-281-4/+4
|/ | | | | | | | Add gnttab_alloc_pages() and gnttab_free_pages() to allocate/free pages suitable to for granted maps. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
* Merge branch 'for-3.18/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2014-10-182-3/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block layer driver update from Jens Axboe: "This is the block driver pull request for 3.18. Not a lot in there this round, and nothing earth shattering. - A round of drbd fixes from the linbit team, and an improvement in asender performance. - Removal of deprecated (and unused) IRQF_DISABLED flag in rsxx and hd from Michael Opdenacker. - Disable entropy collection from flash devices by default, from Mike Snitzer. - A small collection of xen blkfront/back fixes from Roger Pau Monné and Vitaly Kuznetsov" * 'for-3.18/drivers' of git://git.kernel.dk/linux-block: block: disable entropy contributions for nonrot devices xen, blkfront: factor out flush-related checks from do_blkif_request() xen-blkback: fix leak on grant map error path xen/blkback: unmap all persistent grants when frontend gets disconnected rsxx: Remove deprecated IRQF_DISABLED block: hd: remove deprecated IRQF_DISABLED drbd: use RB_DECLARE_CALLBACKS() to define augment callbacks drbd: compute the end before rb_insert_augmented() drbd: Add missing newline in resync progress display in /proc/drbd drbd: reduce lock contention in drbd_worker drbd: Improve asender performance drbd: Get rid of the WORK_PENDING macro drbd: Get rid of the __no_warn and __cond_lock macros drbd: Avoid inconsistent locking warning drbd: Remove superfluous newline from "resync_extents" debugfs entry. drbd: Use consistent names for all the bi_end_io callbacks drbd: Use better variable names
| * xen-blkback: fix leak on grant map error pathRoger Pau Monné2014-10-011-0/+1
| | | | | | | | | | | | | | | | | | Fix leaking a page when a grant mapping has failed. CC: stable@vger.kernel.org Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-and-Tested-by: Tao Chen <boby.chen@huawei.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen/blkback: unmap all persistent grants when frontend gets disconnectedVitaly Kuznetsov2014-10-011-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blkback does not unmap persistent grants when frontend goes to Closed state (e.g. when blkfront module is being removed). This leads to the following in guest's dmesg: [ 343.243825] xen:grant_table: WARNING: g.e. 0x445 still in use! [ 343.243825] xen:grant_table: WARNING: g.e. 0x42a still in use! ... When load module -> use device -> unload module sequence is performed multiple times it is possible to hit BUG() condition in blkfront module: [ 343.243825] kernel BUG at drivers/block/xen-blkfront.c:954! [ 343.243825] invalid opcode: 0000 [#1] SMP [ 343.243825] Modules linked in: xen_blkfront(-) ata_generic pata_acpi [last unloaded: xen_blkfront] ... [ 343.243825] Call Trace: [ 343.243825] [<ffffffff814111ef>] ? unregister_xenbus_watch+0x16f/0x1e0 [ 343.243825] [<ffffffffa0016fbf>] blkfront_remove+0x3f/0x140 [xen_blkfront] ... [ 343.243825] RIP [<ffffffffa0016aae>] blkif_free+0x34e/0x360 [xen_blkfront] [ 343.243825] RSP <ffff88001eb8fdc0> We don't need to keep these grants if we're disconnecting as frontend might already forgot about them. Solve the issue by moving xen_blkbk_free_caches() call from xen_blkif_free() to xen_blkif_disconnect(). Now we can see the following: [ 928.590893] xen:grant_table: WARNING: g.e. 0x587 still in use! [ 928.591861] xen:grant_table: WARNING: g.e. 0x372 still in use! ... [ 929.592146] xen:grant_table: freeing g.e. 0x587 [ 929.597174] xen:grant_table: freeing g.e. 0x372 ... Backend does not keep persistent grants any more, reconnect works fine. CC: stable@vger.kernel.org Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen: remove DEFINE_XENBUS_DRIVER() macroDavid Vrabel2014-10-061-8/+3Star
|/ | | | | | | | | | The DEFINE_XENBUS_DRIVER() macro looks a bit weird and causes sparse errors. Replace the uses with standard structure definitions instead. This is similar to pci and usb device registration. Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* xen-blkback: defer freeing blkif to avoid blocking xenwatchValentin Priescu2014-05-282-14/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently xenwatch blocks in VBD disconnect, waiting for all pending I/O requests to finish. If the VBD is attached to a hot-swappable disk, then xenwatch can hang for a long period of time, stalling other watches. INFO: task xenwatch:39 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ffff880057f01bd0 0000000000000246 ffff880057f01ac0 ffffffff810b0782 ffff880057f01ad0 00000000000131c0 0000000000000004 ffff880057edb040 ffff8800344c6080 0000000000000000 ffff880058c00ba0 ffff880057edb040 Call Trace: [<ffffffff810b0782>] ? irq_to_desc+0x12/0x20 [<ffffffff8128f761>] ? list_del+0x11/0x40 [<ffffffff8147a080>] ? wait_for_common+0x60/0x160 [<ffffffff8147bcef>] ? _raw_spin_lock_irqsave+0x2f/0x50 [<ffffffff8147bd49>] ? _raw_spin_unlock_irqrestore+0x19/0x20 [<ffffffff8147a26a>] schedule+0x3a/0x60 [<ffffffffa018fe6a>] xen_blkif_disconnect+0x8a/0x100 [xen_blkback] [<ffffffff81079f70>] ? wake_up_bit+0x40/0x40 [<ffffffffa018ffce>] xen_blkbk_remove+0xae/0x1e0 [xen_blkback] [<ffffffff8130b254>] xenbus_dev_remove+0x44/0x90 [<ffffffff81345cb7>] __device_release_driver+0x77/0xd0 [<ffffffff81346488>] device_release_driver+0x28/0x40 [<ffffffff813456e8>] bus_remove_device+0x78/0xe0 [<ffffffff81342c9f>] device_del+0x12f/0x1a0 [<ffffffff81342d2d>] device_unregister+0x1d/0x60 [<ffffffffa0190826>] frontend_changed+0xa6/0x4d0 [xen_blkback] [<ffffffffa019c252>] ? frontend_changed+0x192/0x650 [xen_netback] [<ffffffff8130ae50>] ? cmp_dev+0x60/0x60 [<ffffffff81344fe4>] ? bus_for_each_dev+0x94/0xa0 [<ffffffff8130b06e>] xenbus_otherend_changed+0xbe/0x120 [<ffffffff8130b4cb>] frontend_changed+0xb/0x10 [<ffffffff81309c82>] xenwatch_thread+0xf2/0x130 [<ffffffff81079f70>] ? wake_up_bit+0x40/0x40 [<ffffffff81309b90>] ? xenbus_directory+0x80/0x80 [<ffffffff810799d6>] kthread+0x96/0xa0 [<ffffffff81485934>] kernel_thread_helper+0x4/0x10 [<ffffffff814839f3>] ? int_ret_from_sys_call+0x7/0x1b [<ffffffff8147c17c>] ? retint_restore_args+0x5/0x6 [<ffffffff81485930>] ? gs_change+0x13/0x13 With this patch, when there is still pending I/O, the actual disconnect is done by the last reference holder (last pending I/O request). In this case, xenwatch doesn't block indefinitely. Signed-off-by: Valentin Priescu <priescuv@amazon.com> Reviewed-by: Steven Kady <stevkady@amazon.com> Reviewed-by: Steven Noonan <snoonan@amazon.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/blkback: disable discard feature if requested by toolstackOlaf Hering2014-05-281-1/+6
| | | | | | | | | | | Newer toolstacks may provide a boolean property "discard-enable" in the backend node. Its purpose is to disable discard for file backed storage to avoid fragmentation. Recognize this setting also for physical storage. If that property exists and is false, do not advertise "feature-discard" to the frontend. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen-blkback: init persistent_purge_work work_structRoger Pau Monne2014-02-123-2/+3
| | | | | | | | | | | | Initialize persistent_purge_work work_struct on xen_blkif_alloc (and remove the previous initialization done in purge_persistent_gnt). This prevents flush_work from complaining even if purge_persistent_gnt has not been used. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'stable/for-jens-3.14' of ↵Jens Axboe2014-02-103-22/+58
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip into for-linus Konrad writes: Please git pull the following branch: git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git stable/for-jens-3.14 which is based off v3.13-rc6. If you would like me to rebase it on a different branch/tag I would be more than happy to do so. The patches are all bug-fixes and hopefully can go in 3.14. They deal with xen-blkback shutdown and cause memory leaks as well as shutdown races. They should go to stable tree and if you are OK with I will ask them to backport those fixes. There is also a fix to xen-blkfront to deal with unexpected state transition. And lastly a fix to the header where it was using the __aligned__ unnecessarily.
| * xen-blkif: drop struct blkif_request_segment_alignedRoger Pau Monne2014-02-072-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was wrongly introduced in commit 402b27f9, the only difference between blkif_request_segment_aligned and blkif_request_segment is that the former has a named padding, while both share the same memory layout. Also correct a few minor glitches in the description, including for it to no longer assume PAGE_SIZE == 4096. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> [Description fix by Jan Beulich] Signed-off-by: Jan Beulich <jbeulich@suse.com> Reported-by: Jan Beulich <jbeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: fix shutdown raceRoger Pau Monne2014-02-073-10/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a new variable to keep track of the number of in-flight requests. We need to make sure that when xen_blkif_put is called the request has already been freed and we can safely free xen_blkif, which was not the case before. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Reviewed-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: fix memory leaksRoger Pau Monne2014-02-073-9/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I've at least identified two possible memory leaks in blkback, both related to the shutdown path of a VBD: - blkback doesn't wait for any pending purge work to finish before cleaning the list of free_pages. The purge work will call put_free_pages and thus we might end up with pages being added to the free_pages list after we have emptied it. Fix this by making sure there's no pending purge work before exiting xen_blkif_schedule, and moving the free_page cleanup code to xen_blkif_free. - blkback doesn't wait for pending requests to end before cleaning persistent grants and the list of free_pages. Again this can add pages to the free_pages list or persistent grants to the persistent_gnts red-black tree. Fixed by moving the persistent grants and free_pages cleanup code to xen_blkif_free. Also, add some checks in xen_blkif_free to make sure we are cleaning everything. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Reviewed-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: fix memory leak when persistent grants are usedMatt Rushton2014-02-071-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently shrink_free_pagepool() is called before the pages used for persistent grants are released via free_persistent_gnts(). This results in a memory leak when a VBD that uses persistent grants is torn down. Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xen.org Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: Matt Rushton <mrushton@amazon.com> Signed-off-by: Matt Wilson <msw@amazon.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | block: Abstract out bvec iteratorKent Overstreet2013-11-241-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
* xen/blkback: fix reference countingVegard Nossum2013-11-081-1/+2
| | | | | | | | | | | | | | If the permission check fails, we drop a reference to the blkif without having taken it in the first place. The bug was introduced in commit 604c499cbbcc3d5fe5fb8d53306aa0fae1990109 (xen/blkback: Check device permissions before allowing OP_DISCARD). Cc: stable@vger.kernel.org Cc: Jan Beulich <JBeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: replace strict_strtoul() with kstrtoul()Jingoo Han2013-09-121-1/+1
| | | | | | | | | The use of strict_strtoul() is not preferred, because strict_strtoul() is obsolete. Thus, kstrtoul() should be used. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-3.11/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2013-07-233-322/+782
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block IO driver bits from Jens Axboe: "As I mentioned in the core block pull request, due to real life circumstances the driver pull request would be late. Now it looks like -rc2 late... On the plus side, apart form the rsxx update, these are all things that I could argue could go in later in the cycle as they are fixes and not features. So even though things are late, it's not ALL bad. The pull request contains: - Updates to bcache, all bug fixes, from Kent. - A pile of drbd bug fixes (no big features this time!). - xen blk front/back fixes. - rsxx driver updates, some of them deferred form 3.10. So should be well cooked by now" * 'for-3.11/drivers' of git://git.kernel.dk/linux-block: (63 commits) bcache: Allocation kthread fixes bcache: Fix GC_SECTORS_USED() calculation bcache: Journal replay fix bcache: Shutdown fix bcache: Fix a sysfs splat on shutdown bcache: Advertise that flushes are supported bcache: check for allocation failures bcache: Fix a dumb race bcache: Use standard utility code bcache: Update email address bcache: Delete fuzz tester bcache: Document shrinker reserve better bcache: FUA fixes drbd: Allow online change of al-stripes and al-stripe-size drbd: Constants should be UPPERCASE drbd: Ignore the exit code of a fence-peer handler if it returns too late drbd: Fix rcu_read_lock balance on error path drbd: fix error return code in drbd_init() drbd: Do not sleep inside rcu bcache: Refresh usage docs ...
| * xen-blkback: check the number of iovecs before allocating a biosRoger Pau Monne2013-06-251-1/+2
| | | | | | | | | | | | | | | | | | | | | | With the introduction of indirect segments we can receive requests with a number of segments bigger than the maximum number of allowed iovecs in a bios, so make sure that blkback doesn't try to allocate a bios with more iovecs than BIO_MAX_PAGES Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: workaround compiler bug in gcc 4.1Roger Pau Monne2013-06-211-10/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The code generat with gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-54) creates an unbound loop for the second foreach_grant_safe loop in purge_persistent_gnt. The workaround is to avoid having this second loop and instead perform all the work inside the first loop by adding a new variable, clean_used, that will be set when all the desired persistent grants have been removed and we need to iterate over the remaining ones to remove the WAS_ACTIVE flag. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-by: Tom O'Neill <toneill@vmem.com> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen/blkback: Check for insane amounts of request on the ring (v6).Konrad Rzeszutek Wilk2013-06-173-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Check that the ring does not have an insane amount of requests (more than there could fit on the ring). If we detect this case we will stop processing the requests and wait until the XenBus disconnects the ring. The existing check RING_REQUEST_CONS_OVERFLOW which checks for how many responses we have created in the past (rsp_prod_pvt) vs requests consumed (req_cons) and whether said difference is greater or equal to the size of the ring, does not catch this case. Wha the condition does check if there is a need to process more as we still have a backlog of responses to finish. Note that both of those values (rsp_prod_pvt and req_cons) are not exposed on the shared ring. To understand this problem a mini crash course in ring protocol response/request updates is in place. There are four entries: req_prod and rsp_prod; req_event and rsp_event to track the ring entries. We are only concerned about the first two - which set the tone of this bug. The req_prod is a value incremented by frontend for each request put on the ring. Conversely the rsp_prod is a value incremented by the backend for each response put on the ring (rsp_prod gets set by rsp_prod_pvt when pushing the responses on the ring). Both values can wrap and are modulo the size of the ring (in block case that is 32). Please see RING_GET_REQUEST and RING_GET_RESPONSE for the more details. The culprit here is that if the difference between the req_prod and req_cons is greater than the ring size we have a problem. Fortunately for us, the '__do_block_io_op' loop: rc = blk_rings->common.req_cons; rp = blk_rings->common.sring->req_prod; while (rc != rp) { .. blk_rings->common.req_cons = ++rc; /* before make_response() */ } will loop up to the point when rc == rp. The macros inside of the loop (RING_GET_REQUEST) is smart and is indexing based on the modulo of the ring size. If the frontend has provided a bogus req_prod value we will loop until the 'rc == rp' - which means we could be processing already processed requests (or responses) often. The reason the RING_REQUEST_CONS_OVERFLOW is not helping here is b/c it only tracks how many responses we have internally produced and whether we would should process more. The astute reader will notice that the macro RING_REQUEST_CONS_OVERFLOW provides two arguments - more on this later. For example, if we were to enter this function with these values: blk_rings->common.sring->req_prod = X+31415 (X is the value from the last time __do_block_io_op was called). blk_rings->common.req_cons = X blk_rings->common.rsp_prod_pvt = X The RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, blk_rings->common.req_cons) is doing: req_cons - rsp_prod_pvt >= 32 Which is, X - X >= 32 or 0 >= 32 And that is false, so we continue on looping (this bug). If we re-use said macro RING_REQUEST_CONS_OVERFLOW and pass in the rp instead (sring->req_prod) of rc, the this macro can do the check: req_prod - rsp_prov_pvt >= 32 Which is, X + 31415 - X >= 32 , or 31415 >= 32 which is true, so we can error out and break out of the function. Unfortunatly the difference between rsp_prov_pvt and req_prod can be at 32 (which would error out in the macro). This condition exists when the backend is lagging behind with the responses and still has not finished responding to all of them (so make_response has not been called), and the rsp_prov_pvt + 32 == req_cons. This ends up with us not being able to use said macro. Hence introducing a new macro called RING_REQUEST_PROD_OVERFLOW which does a simple check of: req_prod - rsp_prod_pvt > RING_SIZE And with the X values from above: X + 31415 - X > 32 Returns true. Also not that if the ring is full (which is where the RING_REQUEST_CONS_OVERFLOW triggered), we would not hit the same condition: X + 32 - X > 32 Which is false. Lets use that macro. Note that in v5 of this patchset the macro was different - we used an earlier version. Cc: stable@vger.kernel.org [v1: Move the check outside the loop] [v2: Add a pr_warn as suggested by David] [v3: Use RING_REQUEST_CONS_OVERFLOW as suggested by Jan] [v4: Move wake_up after kthread_stop as suggested by Jan] [v5: Use RING_REQUEST_PROD_OVERFLOW instead] [v6: Use RING_REQUEST_PROD_OVERFLOW - Jan's version] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> gadsa
| * xen/blkback: Check device permissions before allowing OP_DISCARDKonrad Rzeszutek Wilk2013-06-071-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to make sure that the device is not RO or that the request is not past the number of sectors we want to issue the DISCARD operation for. This fixes CVE-2013-2140. Cc: stable@vger.kernel.org Acked-by: Jan Beulich <JBeulich@suse.com> Acked-by: Ian Campbell <Ian.Campbell@citrix.com> [v1: Made it pr_warn instead of pr_debug] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen/blkback: Use physical sector size for setupStefan Bader2013-06-071-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently xen-blkback passes the logical sector size over xenbus and xen-blkfront sets up the paravirt disk with that logical block size. But newer drives usually have the logical sector size set to 512 for compatibility reasons and would show the actual sector size only in physical sector size. This results in the device being partitioned and accessed in dom0 with the correct sector size, but the guest thinks 512 bytes is the correct block size. And that results in poor performance. To fix this, blkback gets modified to pass also physical-sector-size over xenbus and blkfront to use both values to set up the paravirt disk. I did not just change the passed in sector-size because I am not sure having a bigger logical sector size than the physical one is valid (and that would happen if a newer dom0 kernel hits an older domU kernel). Also this way a domU set up before should still be accessible (just some tools might detect the unaligned setup). [v2: Make xenbus write failure non-fatal] [v3: Use xenbus_scanf instead of xenbus_gather] [v4: Rebased against segment changes] Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: allocate list of pending reqs in small chunksRoger Pau Monne2013-05-073-78/+106
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allocate pending requests in smaller chunks instead of allocating them all at the same time. This change also removes the global array of pending_reqs, it is no longer necessay. Variables related to the grant mapping have been grouped into a struct called "grant_page", this allows to allocate them in smaller chunks, and also improves memory locality. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-block: implement indirect descriptorsRoger Pau Monne2013-04-183-41/+198
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Indirect descriptors introduce a new block operation (BLKIF_OP_INDIRECT) that passes grant references instead of segments in the request. This grant references are filled with arrays of blkif_request_segment_aligned, this way we can send more segments in a request. The proposed implementation sets the maximum number of indirect grefs (frames filled with blkif_request_segment_aligned) to 256 in the backend and 32 in the frontend. The value in the frontend has been chosen experimentally, and the backend value has been set to a sane value that allows expanding the maximum number of indirect descriptors in the frontend if needed. The migration code has changed from the previous implementation, in which we simply remapped the segments on the shared ring. Now the maximum number of segments allowed in a request can change depending on the backend, so we have to requeue all the requests in the ring and in the queue and split the bios in them if they are bigger than the new maximum number of segments. [v2: Fixed minor comments by Konrad. [v1: Added padding to make the indirect request 64bit aligned. Added some BUGs, comments; fixed number of indirect pages in blkif_get_x86_{32/64}_req. Added description about the indirect operation in blkif.h] Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> [v3: Fixed spaces and tabs mix ups] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: expand map/unmap functionsRoger Pau Monne2013-04-181-55/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Preparatory change for implementing indirect descriptors. Change xen_blkbk_{map/unmap} in order to be able to map/unmap a random amount of grants (previously it was limited to BLKIF_MAX_SEGMENTS_PER_REQUEST). Also, remove the usage of pending_req in the map/unmap functions, so we can map/unmap grants without needing to pass a pending_req. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: make the queue of free requests per backendRoger Pau Monne2013-04-183-105/+74Star
| | | | | | | | | | | | | | | | | | | | | | Remove the last dependency from blkbk by moving the list of free requests to blkif. This change reduces the contention on the list of available requests. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: move pending handles list from blkbk to pending_reqRoger Pau Monne2013-04-181-12/+4Star
| | | | | | | | | | | | | | | | | | | | Moving grant ref handles from blkbk to pending_req will allow us to get rid of the shared blkbk structure. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen-blkback: implement LRU mechanism for persistent grantsRoger Pau Monne2013-04-183-57/+250
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This mechanism allows blkback to change the number of grants persistently mapped at run time. The algorithm uses a simple LRU mechanism that removes (if needed) the persistent grants that have not been used since the last LRU run, or if all grants have been used it removes the first grants in the list (that are not in use). The algorithm allows the user to change the maximum number of persistent grants, by changing max_persistent_grants in sysfs. Since we are storing the persistent grants used inside the request struct (to be able to mark them as "unused" when unmapping), we no longer need the bitmap (unmap_seg). Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-08 12:46:47 +0200